Using Salt to Optimize Mental & Physical Performance | Huberman Lab Podcast #63

Aug 18, 2023

Using Salt to Optimize Mental & Physical Performance | Huberman Lab Podcast #63

I discuss the role of salt (sodium) in the nervous system and the key role that it plays in mental performance, physical performance and health. I explain how the brain senses salt levels in our body and how that relates to our feelings of thirst. I cover the physiology of the renal system and the hormones that control sodium and water balance in our body. I also explore how salt interacts with stress and our immune systems and its crucial role in neuron function. Additionally, I examine research findings suggesting that some individuals might benefit from increased intake of sodium and other electrolytes (magnesium and potassium) to enhance mental performance, lessen anxiety, and offset dizziness. Yet, other people may need less sodium. I discuss how you can determine your optimal sodium intake and why sodium intake levels need to be uniquely tailored to an individual’s lifestyle. Finally, I explain how salt creates ‘hidden’ sugars in many processed foods and the problems that can create. Throughout the episode, I explain peer-reviewed findings outlining salt’s essential role in overall health and describe general recommendations and tools anyone can use to find their optimal salt balance and thereby enhance their brain and body’s performance.

#HubermanLab #Hydration #Salt

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Article Links
“The preference for sugar over sweetener depends on a gut sensor cell”: https://go.nature.com/33X9zuA
“Urinary Sodium and Potassium Excretion and Risk of Cardiovascular Events”: https://bit.ly/3MOJEGW
“Dietary sodium and health: How much is too much for those with orthostatic disorders?“: https://bit.ly/3tSP7UO
“Increased salt consumption induces body water conservation and decreases fluid intake”: https://bit.ly/35PCPVg

Book Links
“The Salt Fix: Why the Experts Got It All Wrong—and How Eating More Might Save Your Life”: https://amzn.to/3CD1KHi

Timestamps
00:00:00 Role of Salt
00:02:18 The Brain-Body Contract
00:02:57 Neuropod Cells, Artificial Sweeteners \u0026 ‘Hidden’ Cravings
00:10:57 AG1 (Athletic Greens), LMNT, InsideTracker
00:15:06 Salt Regulation
00:17:13 How the Brain Senses Salt
00:24:15 Salt \u0026 Thirst
00:29:27 Blood Pressure \u0026 Thirst
00:33:47 Kidneys \u0026 Urine Regulation
00:39:08 Vasopressin: Roles in Libido \u0026 Urination
00:45:46 How Much Salt Do You Need?
00:56:45 Should You Increase Your Salt Intake?
01:02:19 Tools: Determining Your Individual Salt Intake
01:14:02 Iodine, Sea Salt
01:17:13 Salt: Roles in Stress \u0026 Anxiety
01:24:20 Other Electrolytes: Magnesium \u0026 Potassium
01:27:57 Tools: Effects of Low-carbohydrate Diets \u0026 Caffeine
01:32:28 General Recommendations for Salt Intake
01:36:34 Perception of Salt \u0026 Sugar Taste, Processed Foods
01:47:13 Role of Sodium in Neuronal Function, Action Potentials
01:53:13 Dehydration
01:55:36 What Salt Intake is Best for You?
02:00:58 Zero-Cost Support, YouTube Feedback, Spotify, Apple Reviews, Sponsors, Patreon, Thorne, Instagram, Twitter, Neural Network Newsletter

Please note that The Huberman Lab Podcast is distinct from Dr. Huberman’s teaching and research roles at Stanford University School of Medicine. The information provided in this show is not medical advice, nor should it be taken or applied as a replacement for medical advice. The Huberman Lab Podcast, its employees, guests and affiliates assume no liability for the application of the information discussed.

Title Card Photo Credit: Mike Blabac - https://www.blabacphoto.com

Content

0.35 -> - Welcome to the Huberman Lab Podcast,

1.92 -> where we discuss science and science-based tools

4.93 -> for everyday life.

6 -> [authoritative music]

9.33 -> I'm Andrew Huberman,

10.32 -> and I'm a professor of neurobiology and ophthalmology

12.98 -> at Stanford School of Medicine.

14.89 -> Today, we are going to discuss salt,

17.4 -> also referred to as sodium.

19.243 -> Now, most of us think of salt

21.63 -> as something that we put on and in our food,

24.39 -> maybe something to avoid.

25.8 -> Maybe some of you are actually trying to get more salt.

27.8 -> Some of you are trying to get less salt.

29.92 -> We all seem to associate salt

31.48 -> with things like blood pressure, et cetera.

33.47 -> Today, we are going to go down a different set of avenues

36.38 -> related to salt.

37.213 -> We will certainly cover how salt regulates blood pressure.

40.37 -> We are also going to talk about

41.86 -> how the brain regulates our appetite for salt

45.01 -> or our aversion for salt.

47.26 -> We are also going to talk about

48.58 -> how our sensing of salty tastes

51.47 -> actually mediates how much sugar we crave

54.64 -> and whether or not we ingest more or less sugar

57.4 -> than we actually need,

59.05 -> so what you're going to learn today

60.47 -> is that the so-called salt system,

62.5 -> meaning the cells and connections in our brain and body

65.47 -> that mediate salt craving and avoidance,

67.9 -> are regulating many, many aspects of our health

71.55 -> and our ability to perform in various contexts,

73.98 -> things like athletic performance,

75.31 -> things like cognitive performance.

77.54 -> We're also going to talk about aging and dementia

79.82 -> and avoiding aging and dementia

81.42 -> and what role salt and salt avoidance might play in that.

85.52 -> We're going to touch on some themes that,

86.99 -> for some of you, might seem controversial,

88.88 -> and indeed, if they are controversial,

90.6 -> I'll be sure to highlight them as such.

92.52 -> I'm going to cover a lot of new data

94.28 -> that point to the possibility,

95.97 -> I want to emphasize the possibility,

97.23 -> that for some people, more salt might help them

100.93 -> in terms of health, cognitive, and bodily functioning,

104.08 -> and for other people, less salt is going to be better.

107.44 -> I'm going to talk about what the various parameters are.

109.54 -> I'm going to give you some guidelines that,

111.33 -> in concert with your physician,

113.23 -> who you should absolutely talk to

114.43 -> before adding or changing anything

116.06 -> to your diet or supplementation regime,

117.92 -> can help you arrive at a salt intake

119.93 -> that's going to optimize your mental,

121.3 -> physical health, and performance,

123.3 -> so we're going to cover neurobiology.

124.54 -> We're going to cover hormone biology.

126.36 -> We're going to talk about liver function.

127.65 -> We're going to talk about kidney function

129.6 -> and, of course, brain function.

131.45 -> I'm excited to share this information with you today.

133.61 -> I'm certain you're going to come away with a lot of information

136.48 -> and actionable items.

138.09 -> I'm pleased to announce

139.02 -> that I'm hosting two live events this May.

141.37 -> The first live event will take place

142.84 -> in Seattle, Washington on May 17th.

145.45 -> The second live event will take place

146.94 -> in Portland, Oregon on May 18th.

149.9 -> Presale tickets for these two events are now available

152.36 -> at hubermanlab.com/tour.

155.25 -> I should mention that

156.18 -> while I do hope to visit other cities in the near future

159.24 -> to do more live events,

160.47 -> right now,

161.303 -> these are the only two live events I have scheduled,

163.36 -> at least for the six months,

165 -> so once again, if you go to hubermanlab.com/tour,

167.61 -> you can access the presale tickets.

169.49 -> I hope to see you at these live events,

171.38 -> and as always, thank you for your interest in science.

174.36 -> Before we dive into the topic of today's episode,

177.17 -> I want to highlight a really exciting new study.

179.81 -> This is a study from Diego Bohorquez' lab

182.29 -> at Duke University.

184.17 -> The Bohorquez Lab studies interactions

186.54 -> between the gut and the brain

188.87 -> and has made some incredible discoveries

191.22 -> of the so-called neuropod cells.

193.35 -> Neuropod cells are neurons, nerve cells,

195.89 -> that reside in our gut

197.84 -> and that detect things like fatty acids, amino acids,

201.32 -> and some neuropod cells sense sugar.

204.41 -> Previous work from this laboratory has shown

206.9 -> that when we ingest sugar,

209.27 -> these neuropod cells respond to that sugar

212.89 -> and send electrical signals

214.57 -> up a little wire that we call an axon

216.54 -> through the vagus nerve, for those of you that want to know,

219.04 -> and into the brain,

220.97 -> and through subsequent stations of neural processing,

224.06 -> evoke the release of dopamine.

226.43 -> Dopamine is a molecule known to promote craving

229.95 -> and motivation and indeed action,

232.54 -> and what these neuropod cells that send sugar

234.67 -> are thought to do is to promote seeking and consumption,

238.18 -> eating of more sugary foods.

240.96 -> Now, the incredible thing is that it's all subconscious.

243.61 -> This is a taste system in the gut

246.1 -> that is not available to your conscious awareness.

249.6 -> Now, of course, when you ingest sweet foods,

251.36 -> you taste them on your mouth too,

252.92 -> and so part of the reason

254.17 -> that you crave sweet foods, perhaps,

256.09 -> is because they taste good to you,

257.84 -> and the other reason

259.5 -> is that these neuropod cells are driving a chemical craving

263.3 -> below your conscious detection,

264.79 -> so they're really two systems.

266.4 -> Your gut is sensing, at a subconscious level, what's in it

271.42 -> and sending signals to your brain that work in concert,

274.07 -> in parallel with the signals coming from your mouth

276.42 -> and your experience of the taste of the food.

278.68 -> Now, that alone is incredible,

280.62 -> and it's been the subject of many important landmark papers

283.22 -> over the last decade or so.

285.45 -> You can imagine how this system would be very important

287.97 -> for things like hidden sugars

289.3 -> when nowadays, in a lot of processed foods,

291.61 -> they're putting hidden sugars.

293.67 -> They're putting a lot of things

295.24 -> that cause your gut to send signals to your brain

298.85 -> that make you crave more of those foods,

301.2 -> so for those of you that really love sugar,

302.82 -> just understand it's not just about how that sugar tastes.

306.48 -> The new study from the Bohorquez Lab

308.02 -> deserves attention, I believe.

309.97 -> This is a paper published just recently,

311.94 -> February 25th this year, 2022,

314.72 -> in "Nature Neuroscience," an excellent journal,

316.8 -> and the title of the paper is

318.287 -> "The Preference for Sugar over Sweetener

320.397 -> "Depends on a Gut Sensor Cell."

322.56 -> The Bohorquez Lab has now discovered a neuropod cell,

326.01 -> meaning a category of neurons,

327.77 -> that can distinguish between sweet things in the gut

332.33 -> that contain calories, for instance, sugar,

336.38 -> and things in the gut that are sweet

340.19 -> but do not contain calories:

342.01 -> artificial sweeteners like aspartame, sucralose,

344.28 -> and so forth.

345.81 -> There are also, of course,

346.7 -> nonartificial, noncaloric sweeteners

348.94 -> like stevia, monk fruit, et cetera.

351.39 -> They did not explore

352.3 -> the full gallery of artificial sweeteners.

354.69 -> What they did find, however, ought to pertain

357.47 -> to all forms of sweet, noncaloric substances.

361.43 -> What they discovered

362.263 -> was that there is a signature pattern of signals

364.48 -> sent from the gut to the brain

366.72 -> when we ingest artificial or noncaloric sweeteners.

371.07 -> This is important

371.97 -> because what it says is that at a subconscious level,

374.3 -> the gut can distinguish

375.39 -> between sweet things that contain calories

377.15 -> and sweet things that do not.

378.64 -> Now, what the downstream consequences of this sensing is

383.41 -> or what they are isn't yet clear.

386.44 -> Now, I believe everyone

387.37 -> should be aware of these kinds of studies

389.72 -> for a couple of reasons.

390.7 -> First of all,

392.06 -> it's important to understand that what you crave,

394.52 -> meaning the foods you crave and the drinks you crave,

396.83 -> is, in part, due to your conscious experience

399.32 -> of the taste of those things,

400.85 -> but also due to biochemical and neural events

404.25 -> that start in the body and impinge on your brain

407.61 -> and cause you to seek out certain things

410.72 -> even though you might not know

412.03 -> why you're seeking out more sugar.

413.6 -> You find that you're craving a lot of sugar,

415.56 -> or you're craving a lot of foods with artificial sweeteners,

418.12 -> and you don't necessarily know why.

419.92 -> Now, artificial sweeteners themselves

421.57 -> are a somewhat controversial topic.

423.39 -> I want to highlight that.

425.1 -> Some months back, I described a study from Yale University

428.84 -> about how one can condition the insulin system.

431.79 -> Insulin is involved in mobilizing of blood sugar

433.99 -> and so forth in the body, as many of you know,

435.91 -> and I described some studies

438.12 -> that were done from Yale University School of Medicine

440.46 -> looking at how artificial sweeteners

442.3 -> can actually evoke an insulin response

447.13 -> under certain conditions.

449.06 -> Now, a couple of key things.

450.81 -> I got a little bit of pushback after covering those studies,

454.42 -> and I encourage pushback all the time.

457.41 -> Pushback is one of those things

458.59 -> that forces all of us to drill deeper into a topic.

461.32 -> I want to be clear.

462.153 -> First of all,

462.986 -> I am not one to demonize artificial sweeteners.

465.73 -> There is evidence, in animal models,

467.96 -> in animal models,

469.38 -> that artificial sweeteners can disrupt the gut microbiome,

473.28 -> but those were fairly high doses of artificial sweeteners,

475.75 -> and it's unclear if the same thing pertains to humans,

477.98 -> still unclear, I should say,

479.38 -> has not been investigated thoroughly.

481.46 -> Some people don't like the taste of artificial sweeteners.

483.64 -> Some people do.

484.51 -> Some people find

485.343 -> that they really help them avoid excessive caloric intake.

488.49 -> Some people believe,

489.73 -> and yet I should emphasize there still isn't evidence

492.55 -> that they can adjust the insulin response in all people.

495.33 -> I just want to repeat that three times

496.64 -> so that people are clear on that fact.

500.06 -> What these new data emphasize, however,

501.94 -> is that we need to understand

503.48 -> how artificial sweeteners are consumed

506.32 -> at the level of the gut,

507.153 -> or I should say registered at the level of the gut

509.16 -> and how that changes brain function

511.91 -> because one thing that I'm familiar with

513.127 -> and that many people report

514.5 -> is that when they first taste artificial sweeteners,

517.27 -> they taste sort of not right to them.

519.29 -> They don't like the taste,

520.16 -> but over time, they actually start to crave that taste.

522.9 -> I've experienced this.

523.733 -> I used to drink a lot of diet sodas

525.04 -> when I was in graduate school,

526.51 -> so this would be aspartame,

527.99 -> and I found that I would, I actually needed them.

530.75 -> Now, maybe it was the caffeine.

531.81 -> Maybe I just liked the sweet taste or the carbonation.

533.8 -> We actually have a drive for carbonation,

536.24 -> which is a topic of a future episode,

538.31 -> but when I finally quit them,

541.1 -> for reasons that were independent

542.78 -> of any fear of artificial sweeteners,

545.55 -> I found that I didn't like the taste.

547.35 -> Nowadays, I only occasionally drink a diet soda.

550.48 -> I usually do that if I'm on a plane

551.65 -> and there's nothing else available to me,

552.93 -> so I don't demonize them.

554.31 -> I might drink one every once in a while.

556.53 -> No big deal.

557.363 -> I also want to be clear I consume stevia

559.14 -> on a number of different supplements

561.13 -> and foods that I consume.

562.51 -> Stevia, of course, is a plant-based noncaloric sweetener,

565.35 -> so I, myself, consume artificial sweeteners.

567.57 -> Many people hate them.

568.91 -> Many people like them

570.44 -> and find them useful for their nutrition,

572.33 -> and in fact, to keep their caloric intake

574.53 -> in a range that's right for them,

576.29 -> and many people, like myself,

578.64 -> are curious about them and somewhat wary of them

581.9 -> and yet continue to consume them in small amounts.

584.21 -> I think most people probably fall into that category.

586.44 -> I should also mention that many food manufacturers

589.81 -> put artificial sweeteners,

591.4 -> such as sucralose, et cetera, into foods,

594.4 -> and it's always been unclear

596.26 -> as to why they might want to do that,

598.21 -> and yet we know that the sweet taste consumption,

602.27 -> even if it doesn't contain calories,

603.64 -> can drive more craving of sweet food,

606.73 -> so there may be a logic or a strategy to why they do that.

609.67 -> Again, a topic for exploration on today's podcast

612.33 -> and in future podcasts

613.26 -> because where we're headed today

615.21 -> is a discussion about how salt and salt sensing,

618.84 -> both consciously and unconsciously,

620.77 -> can adjust our craving for other things,

622.89 -> like sugar and water and so on,

625.35 -> so I want to highlight this beautiful work

627.01 -> from the Bohorquez Lab.

627.843 -> We'll put a link to the study.

629.38 -> I want to open this as a chapter for further exploration.

632.54 -> I like to think that the listeners of this podcast

635.12 -> are looking for answers where we have answers,

637 -> but are also, I would hope,

638.72 -> excited about some of the new and emerging themes

641.23 -> in what we call nutritional neurobiology,

643.58 -> and indeed, the Bohorquez Lab really stands

645.96 -> as one of the premier laboratories out there

648.43 -> that's looking at how foods, as consumed in the gut,

652.07 -> are modifying our nervous system,

653.82 -> the foods we crave, and how we utilize those foods.

656.86 -> Before where we begin,

657.7 -> I'd like to emphasize that this podcast is separate

659.87 -> from my teaching and research roles at Stanford.

662.04 -> It is, however, part of my desire and effort

664.37 -> to bring zero cost to consumer information

666.27 -> about science and science-related tools

668.27 -> to the general public.

669.74 -> In keeping with that theme,

670.77 -> I'd like to thank the sponsors of today's podcast.

673.39 -> Our first sponsor is Athletic Greens, now called AG1.

677.05 -> I've been taking AG1 since 2012,

679.38 -> so I'm delighted that they're sponsoring the podcast.

681.68 -> The reason I started taking AG1

682.927 -> and the reason I still take AG1 once or twice a day

685.95 -> is that I find it to be the best way

688.22 -> to ensure I get all of my vitamins and minerals

690.6 -> and the probiotics I need.

692.55 -> I try and eat really well, but I'm not perfect about it,

695.6 -> and with Athletic Greens, AG1,

698.34 -> I cover any deficiencies I might have.

700.76 -> The probiotics are particularly important to me

703.15 -> because, as we've talked about on many previous episodes

705.91 -> and we'll talk about more on today's episode,

707.83 -> the gut microbiome is supported by probiotics,

710.3 -> and the gut microbiome supports many biological functions

713.47 -> important for immediate and long-term health,

715.35 -> things like immune system function,

716.89 -> things like the gut-brain axis

718.52 -> and mood and appetite and so forth.

720.52 -> With Athletic Greens,

721.55 -> I make sure all of those bases are covered

723.32 -> because of the probiotics.

724.51 -> If you'd like to try Athletic Greens,

725.88 -> you can go to athleticgreens.com/huberman

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737.49 -> Vitamin D3 is crucial

739.35 -> for many aspects of our immediate and long-term health,

742.79 -> and many people simply are not getting enough vitamin D3,

745.8 -> or the amounts they're getting are not optimal.

748.15 -> K2 is important for cardiovascular health

750.44 -> and for calcium regulation,

751.7 -> so again, if you go to athleticgreens.com/huberman,

754.56 -> you can claim the special offer,

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759.6 -> Today's episode is also brought to us by LMNT.

762.25 -> LMNT is an electrolyte drink that has everything you need

765.35 -> and none of the things you don't.

767.81 -> That means it has salt, magnesium, and potassium,

770.507 -> the so-called electrolytes,

771.86 -> which are critical for neuronal function

773.8 -> and a lot of other biological functions.

777.13 -> As I mentioned on the podcast before,

778.8 -> I'm a fan of salt.

780.24 -> I believe in ingesting appropriate amounts of salt,

782.51 -> and by appropriate, I mean,

783.61 -> depending on what your background blood pressure

785.76 -> happens to be,

786.593 -> what your activity levels are, how much you sweat,

788.85 -> what your cognitive and physical demands are.

790.67 -> Today, we're going to talk about

791.98 -> how to determine what those needs are.

794.7 -> I'm always trying to stay on top of my hydration,

797.4 -> and as you'll also learn about today,

799.48 -> salt and water intake and hydration are intimately related.

803.63 -> With LMNT, I'm sure to get the potassium, the sodium,

807.447 -> and the magnesium that I need,

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830.91 -> Today's episode is also brought to us by InsideTracker.

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836.3 -> that analyzes data from your blood and DNA

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842.53 -> I am a big fan of getting regular blood work done,

844.97 -> and I've been trying to do it

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856.21 -> With most blood tests and DNA tests, however,

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863.35 -> so if something's in high or low range,

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906.96 -> Okay, let's talk about salt.

908.34 -> Salt has many, many important functions

910.19 -> in the brain and body.

911.64 -> For instance, it regulates fluid balance,

914.24 -> how much fluid you desire and how much fluid you excrete.

918.71 -> It also regulates your desire for salt itself,

922.2 -> meaning your salt appetite.

924.09 -> You have a homeostatically driven salt appetite.

928.05 -> I'll talk about the mechanisms today,

929.4 -> make them all very clear.

931.33 -> What that means is that you crave salty things,

934.39 -> beverages and foods,

935.71 -> when your salt stores are low,

937.5 -> and you tend to avoid salty beverages and foods

940.8 -> when your salt stores are high,

942.35 -> although that's not always the case.

943.92 -> There are circumstances where you'll continue to crave salt

946.79 -> even though you don't need salt

948.61 -> or indeed even if you need to eliminate salt

951.94 -> from your system.

953.86 -> Salt also regulates your appetite for other nutrients,

956.76 -> things like sugar, things like carbohydrates,

959.4 -> and today, we'll explore all of that.

961.55 -> Technically, salt is a mineral,

964.04 -> and I should mention that when I say salt,

966.51 -> I am indeed referring to sodium, in most cases,

969.16 -> although I will be clear to distinguish salt from sodium,

971.88 -> meaning table salt from sodium.

974.08 -> Most people don't realize this,

976.07 -> but one gram of table salt

978.63 -> contains about 388 milligrams of sodium,

982.93 -> so technically, we should be talking about sodium today

985.71 -> and not salt.

986.543 -> I will use them interchangeably

988 -> unless I'm referring to some specific recommendations

991.88 -> or ideas about trying to define your ideal salt,

996.34 -> aka sodium intake, okay?

998.31 -> So this is important.

999.27 -> I think, right off the bat,

1000.98 -> a lot of people get themselves into a place of confusion

1003.77 -> and potentially even to a place of trouble

1006.13 -> by thinking that table salt in grams

1009.23 -> always equates to sodium in grams,

1011.677 -> and that's simply not the case.

1013.94 -> Today, we're going to explore the neural mechanisms

1016.97 -> by which we regulate our salt appetite

1020.64 -> and the way that the brain and body interact

1022.81 -> in the context of salt-seeking, salt avoidance,

1026.25 -> how to determine when we need more salt,

1028.07 -> when we need less salt.

1029.49 -> We'll talk about kidney function.

1030.89 -> We'll get into all of it,

1032.37 -> and we're going to do it very systematically,

1034.12 -> so let's start in the brain.

1036.28 -> We all harbor small sets of neurons.

1039.83 -> We call these sets of neurons nuclei,

1041.82 -> meaning little clusters of neurons,

1044.35 -> that sense the levels of salt in our brain and body.

1048.7 -> There are couple brain regions that do this,

1051.04 -> and these brain regions are very, very special,

1053.23 -> special because they lack biological fences around them

1057.483 -> that other brain areas have,

1059.4 -> and those fences, or I should say that fence,

1062.38 -> goes by a particular name,

1063.49 -> and that name is the blood-brain barrier, or BBB.

1067.72 -> Most substances that are circulating around in your body

1070.66 -> do not have access to the brain,

1072.59 -> in particular, large molecules

1074.49 -> can't just pass into the brain.

1076.55 -> The brain is a privileged organ in this sense.

1079 -> There are couple other organs that are privileged

1080.89 -> and that have very strict barriers,

1083.21 -> very particular fences, if you will,

1085.597 -> and those other organs

1086.7 -> include things like the ovaries and testes,

1088.65 -> and that makes sense for the following reason:

1091.25 -> First of all, the brain, at least most of the brain,

1095.32 -> cannot regenerate after injury.

1098.04 -> You just simply can't replace brain cells after injury.

1100.55 -> I know people get really excited about neurogenesis,

1102.87 -> the birth of new neurons,

1103.97 -> and indeed, neurogenesis has been demonstrated

1106.65 -> in animal models,

1107.57 -> and to some extent it exists in humans in a few places,

1110.52 -> for instance, the olfactory bulb,

1112.45 -> where neurons are responsible

1114.5 -> for detecting odorants in the environment,

1116.47 -> for smell, that is,

1117.47 -> and in a little subregion of the hippocampus, a memory area,

1120.87 -> there's probably some neurogenesis,

1122.82 -> but the bulk of really good data out there

1124.75 -> point to the fact that in humans

1126.44 -> there's not much turnover of neurons.

1128.7 -> What that means is that the neurons you're born with

1131.21 -> are the ones that you're going to be using

1133.63 -> most, if not all, of your life.

1136.28 -> In fact, you're born with many more neurons

1138.3 -> than you'll have later,

1139.6 -> and there's a process of naturally occurring cell death

1142.08 -> called apoptosis, that occurs during development,

1144.43 -> so you actually are born with many more neurons

1146.48 -> than you have later in life,

1147.4 -> and that's the reflection of a normal, healthy process

1150.57 -> of nerve cell elimination,

1153.08 -> so the estimates vary,

1155.1 -> but anywhere from 1/3 to maybe even 1/2

1158.06 -> or even 2/3 of neurons, depending on the brain area,

1160.28 -> are just going to die across development.

1162.09 -> That might sound terrible,

1163.19 -> but that's actually one of the ways

1164.29 -> in which you go from being kind of like a little potato bug

1166.89 -> flopping around helplessly in your crib

1168.82 -> to being an organism that can walk and talk

1171.18 -> and articulate and calculate math

1174.22 -> or do whatever it is that you do for a living,

1176.5 -> so the brain has a set of elements,

1179.92 -> these nerve cells and other cells,

1181.51 -> and it needs to use those for the entire lifespan,

1184.62 -> so having a BBB, a blood-brain barrier around the brain,

1187.24 -> is absolutely critical.

1189.14 -> The ovaries and testes have a barrier for, we assume,

1193.86 -> the reason that they contain the genetic material

1196.34 -> by which we can pass on our genes to our offspring,

1199.37 -> progeny, meaning make children,

1200.65 -> and those children will have our genes,

1202.68 -> or at least half of them,

1204.58 -> the other half from the partner, of course.

1208.17 -> If the cells within the ovaries and testes are mutated,

1212.92 -> well, then, you can get mutations in offspring,

1214.76 -> so that's very costly in the evolutionary sense,

1217.11 -> so it makes sense

1217.943 -> that you would have a barrier from the blood

1219.84 -> so if you ingest what's called a mutagen,

1221.73 -> if you ingest something that can mutate the genes of cells,

1225.08 -> you can imagine why there would be a premium

1228.93 -> on not allowing those mutagens

1230.44 -> to get into the brain, the ovaries, or the testes, okay?

1233.53 -> So the brain has this BBB,

1234.99 -> this blood-brain barrier around it,

1236.49 -> which makes it very, very hard

1237.56 -> for substances to pass into the brain

1239.08 -> unless those substances are very small

1241.15 -> or those substances and molecules

1244.17 -> are critically required for brain function.

1246.95 -> However, there are a couple of regions in the brain

1250.68 -> that have a fence around them,

1253.94 -> but that fence is weaker, okay?

1255.61 -> It's sort of like going from a really big wall

1257.87 -> thick electronic 24-hour surveillance fence

1262.3 -> where nothing can pass through

1263.48 -> except only the exclusive cargo that's allowed to go through

1266.97 -> to having a little cyclone fence with a couple holes in it,

1269.73 -> or it's a kind of a picket fence that's falling over,

1272.29 -> and substances can move freely in

1274.25 -> from the blood circulating in the body into the brain,

1277.62 -> and it turns out that the areas of the brain

1279.44 -> that monitor salt balance

1281.53 -> and other features of what's happening in the body

1284.58 -> at the level of what we call osmolarity,

1287.58 -> at the concentration of salt,

1291.09 -> reside in these little sets of neurons

1294.56 -> that sit just on the other side of these weak fences,

1297.47 -> and the most important and famous of these,

1299.82 -> for sake of today's conversation, is one called OVLT.

1303.54 -> OVLT stands for

1304.91 -> the organum vasculosum of the lateral terminalis.

1308.07 -> It is what's called a circumventricular organ.

1310.72 -> Why circumventricular?

1311.87 -> Well, not to bog you down with neuroanatomy,

1314.23 -> but your brain is a big squishy mass

1317.2 -> of neurons and other cell types,

1319.01 -> but it has to be nourished,

1320.88 -> and through the middle of that brain,

1323.53 -> there is a tube, there's a hollow, that creates spaces,

1326.687 -> and those spaces are called ventricles.

1328.93 -> The ventricles are spaces

1330.02 -> in which cerebrospinal fluid circulates,

1333.86 -> and it nourishes the brain.

1335.09 -> It does a number of other things as well.

1337.84 -> The circumventricular organs

1340.37 -> are areas of the brain that are near that circulating fluid,

1343.82 -> and that circulating fluid has access to the bloodstream,

1346.61 -> and the bloodstream has access to it,

1348.23 -> and this structure that I'm referring to,

1350.11 -> OVLT, organum vasculosum of the lateral terminalis,

1353.46 -> has neurons that can sense

1355.91 -> the contents of the blood

1358.7 -> and, to some extent, the cerebrospinal fluid.

1361.2 -> There are couple other brain areas that can do this as well.

1364.34 -> They go also by the name of circumventricular organs,

1367.87 -> and I'll talk about the names of some of those other areas,

1370.13 -> but for today,

1371.3 -> and I think for sake of most of the discussion,

1373.32 -> understand that the OVLT is special.

1375.51 -> Why?

1376.343 -> Because it doesn't have this thick barrier fence,

1378.74 -> which sounds like a bad thing,

1380.39 -> and yet it's a terrific border detector.

1384.48 -> The neurons in that region

1387.16 -> are able to pay attention

1388.36 -> to what's passing through in the bloodstream

1390.9 -> and can detect, for instance,

1392.67 -> if the levels of sodium in the bloodstream are too low,

1395.3 -> if the level of blood pressure in the body

1397.33 -> is too low or too high,

1398.6 -> and then, the OVLT can send signals to other brain areas,

1402.93 -> and then, those other brain areas can do things

1405.2 -> like release hormones that can go and act on tissues

1408.54 -> in what we call the periphery, in the body,

1411.56 -> and, for instance, have the kidneys secrete more urine

1416.06 -> to get rid of salt that's excessive salt in the body

1419.41 -> or have the kidneys hold onto urine,

1421.84 -> to hold onto whatever water or fluid that one might need,

1425.14 -> so before I go any deeper into this pathway,

1427.06 -> just understand that the OVLT has a very limited barrier.

1430.49 -> It can detect things in the bloodstream,

1432.4 -> and this incredible area of the brain,

1435.83 -> almost single-handedly,

1437.38 -> sets off the cascades of things

1439.11 -> that allow you to regulate your salt balance,

1442.05 -> which turns out to be absolutely critical,

1444.13 -> not just for your ability to think

1445.7 -> and for your neurons to work,

1446.8 -> but indeed, for all of life.

1448.45 -> If the OVLT doesn't function correctly,

1450.35 -> you're effectively dead or dead soon,

1452.75 -> so this is a very important brain region,

1455.01 -> so let's talk about the function of the OVLT

1457.12 -> and flesh out some of the other aspects of its circuitry,

1460.39 -> of its communication with other brain areas

1462.35 -> and with the body

1463.19 -> in the context of something that we are all familiar with,

1465.65 -> which is thirst.

1467.12 -> Have you ever wondered just why you get thirsty?

1469.94 -> Well, it's because neurons in your OVLT

1473.38 -> are detecting changes in your bloodstream,

1475.56 -> which detect global changes within your body,

1478.57 -> and in response to that,

1480.143 -> your OVLT sets off certain events within your brain and body

1484.81 -> that make you either want to drink more fluid

1487.4 -> or to stop drinking fluid.

1490.62 -> There are two main kinds of thirst.

1492.4 -> The first one is called osmotic thirst,

1494.9 -> and the second is called hypovolemic thirst.

1498.94 -> Osmotic thirst has to do

1500.33 -> with the concentration of salt in your bloodstream,

1503.23 -> so let's say you ingest something very, very salty.

1505.5 -> Let's say you ingest a big bag of,

1508.25 -> I confess I don't eat these very often,

1509.88 -> but I really like those kettle potato chips,

1511.76 -> and they're pretty salty.

1512.66 -> I've never actually measured how much sodium is in them.

1514.63 -> I'm sure the information is there.

1515.77 -> Every once in a while,

1517.6 -> I'm particularly interested in doing so,

1520.97 -> I'll just down a bag of those things,

1522.48 -> and I really like them, and they're very salty,

1524.36 -> but they almost always make me feel thirsty,

1526.53 -> and the reason is that by eating those,

1528.96 -> I've ingested a lot of sodium.

1530.37 -> Again, not a frequent occurrence for me,

1532.55 -> but happens every now and again,

1534.81 -> and I don't have too much shame about that

1536.61 -> because I think I have a pretty healthy relationship to food

1539.46 -> and I enjoy them,

1540.87 -> and I understand

1542.22 -> that it will drive salt levels up in my bloodstream,

1545.72 -> and that will cause me to be thirsty, but why?

1549.05 -> Why?

1549.883 -> Because neurons in the OVLT come in two main varieties.

1553.81 -> One variety senses the osmolarity of the blood

1557.8 -> that's getting across that weak little fence

1559.92 -> that we talked about before,

1561.42 -> and when the osmolarity,

1563.04 -> meaning the salt concentration of the blood, is high,

1566.41 -> it activates these specific neurons in the OVLT,

1569.34 -> and by activates,

1570.19 -> I mean it causes them to send electrical potentials,

1573.2 -> literally, send electrical signals to other brain areas,

1577.69 -> and those other brain areas

1579.05 -> inspire a number of different downstream events,

1581.96 -> so what are those other brain areas?

1583.97 -> Well, the OVLT

1586.52 -> signals to an area called the supraoptic nucleus.

1590.36 -> The name and why it's called the supraoptic nucleus

1593.29 -> is not necessarily important.

1594.97 -> It also signals to the so-called paraventricular nucleus,

1597.86 -> another nucleus that sits near the ventricles

1599.82 -> and can monitor the qualities,

1603 -> the chemical qualities of the cerebrospinal fluid

1605.53 -> as well as, probably, the bloodstream as well,

1608.37 -> and the consequence

1611.86 -> of that communication

1613.61 -> is that a particular hormone is eventually released

1617.22 -> from the posterior pituitary.

1619.72 -> Now, the pituitary is a gland

1622.81 -> that sits near the roof of your mouth.

1625.13 -> It releases all sorts of things

1626.47 -> like growth hormone and luteinizing hormone.

1629.43 -> Luteinizing hormone will stimulate things

1631.16 -> like estrogen and testosterone production and release

1635.02 -> from the ovaries and testes and so on.

1637.64 -> The pituitary has a bunch

1638.75 -> of different compartments and functions,

1640.07 -> but what's really cool about the pituitary

1642.6 -> is that certain regions of the pituitary

1644.54 -> actually contain the axons, the wires of neurons,

1647.49 -> and the neurons reside in the brain,

1649.59 -> and so the supraoptic nucleus gets a signal from the OVLT.

1654.95 -> The signal is purely in the form of electrical activity.

1657.44 -> Remember, neurons aren't talking in one another

1659.44 -> about what's happening out there.

1660.77 -> They're not saying, "Psst!

1661.603 -> "Hey, there's too much salt in the bloodstream.

1664.227 -> "Let's do something about it."

1665.46 -> All they receive are so-called action potential,

1667.86 -> waves of electricity.

1669.49 -> The neurons in the supraoptic nucleus

1671.85 -> then release their own electrical signals

1676.01 -> within the pituitary,

1677.64 -> and some of those neurons and nearby neurons

1680.5 -> are capable of releasing hormones

1682.7 -> as well as electrical signals,

1685.38 -> so from the pituitary,

1687.15 -> there's a hormonal signal that's released

1688.84 -> called vasopressin.

1690.95 -> Vasopressin also goes by the name antidiuretic hormone,

1695.56 -> and antidiuretic hormone has the capacity

1699.75 -> to either restrict the amount of urine that we secrete,

1703.81 -> or, when that system is turned off,

1706.13 -> to increase the amount of urine that we secrete,

1709.64 -> so there's a complicated set of cascades that's evoked

1713.53 -> by having high salt concentration in the blood.

1715.96 -> There's also a complicated set of cascades that are evoked

1718.84 -> by having low concentrations of sodium in the blood,

1722.25 -> but the pathway is nonetheless the same.

1724.22 -> It's OVLT is detecting those osmolarity changes,

1728.09 -> communicating to the supraoptic nucleus.

1729.73 -> Supraoptic nucleus is either causing the release of

1734.38 -> or is releasing vasopressin, antidiuretic hormone,

1737.85 -> or that system is shut off

1739.87 -> so that the antidiuretic hormone is not secreted,

1743.52 -> which would allow urine to flow more freely, right?

1746.27 -> Antidiuretic means anti release of urine,

1750.48 -> and by shutting that off,

1752.78 -> you are going to cause the release of urine.

1755.97 -> You're sort of allowing a system to flow, so to speak.

1758.76 -> The second category of thirst is hypovolemic thirst.

1763.26 -> Hypovolemic thirst occurs

1764.76 -> when there's a drop in blood pressure, okay?

1767.85 -> So the OVLT, as I mentioned before,

1769.78 -> can sense osmolarity

1772.58 -> based on the fact that it has these neurons

1774.49 -> that can detect how much salt is in the bloodstream,

1778.06 -> but the OVLT also harbors neurons

1781.49 -> that are of the baroreceptor,

1784.2 -> mechanoreceptor category.

1786.86 -> Now, more on baroreceptors and mechanoreceptors later,

1790.86 -> but baroreceptors are essentially a receptor,

1795.89 -> meaning a protein that's in a cell

1798.26 -> that responds to changes in blood pressure,

1801.6 -> so there are a number of things

1802.81 -> that can cause decreases in blood pressure.

1805.91 -> Some of those include, for instance,

1807.24 -> if you lose a lot of blood, right?

1808.94 -> If you're bleeding quite a lot,

1810.64 -> or in some cases, if you vomit quite a lot,

1814.28 -> or if you have extensive diarrhea

1816.46 -> or any combination of those,

1817.83 -> and there are other things that can reduce blood volume,

1820.73 -> and we will talk about some of those later,

1823.29 -> but in the classic case of hypovolemic thirst,

1827.49 -> one is simply losing blood,

1829.48 -> and therefore, blood pressure goes down,

1831.21 -> so very simple to imagine in your mind.

1833.09 -> You have these pipes,

1833.923 -> which are the arteries, veins, and capillaries,

1835.37 -> and when you lose some blood volume,

1837.28 -> the pressure in those arteries, veins, and capillaries

1840.01 -> goes down.

1840.843 -> OVLT has neurons

1842.473 -> that can sense that reduction in blood pressure

1845.739 -> because of the presence of baroreceptors in OVLT.

1849.58 -> There are other elements

1852.31 -> that also play into the response

1854.47 -> to what we call hypovolemic thirst.

1857.61 -> For instance,

1859.44 -> the kidney will secrete something called renin.

1862.28 -> Renin will activate something called angiotensin II

1865.09 -> from the lungs, of all things, amazing,

1868.36 -> and angiotensin II itself can act on OVLT,

1872.206 -> organum vasculosum of the lateral terminalis,

1874.33 -> which, in turn, will create thirst, okay?

1878.84 -> So in both cases, right?

1881.23 -> The osmolarity sensing system, meaning osmotic thirst,

1884.73 -> and in hypovolemic thirst, where blood pressure has dropped,

1888.68 -> the end result is a desire to drink more,

1891.74 -> and that desire to drink more

1893.35 -> comes through a variety of pathways

1894.86 -> that are both direct and indirect,

1896.44 -> include vasopressin and don't include vasopressin,

1898.83 -> but I think, for just sake of general example,

1902.29 -> and even for those of you

1903.2 -> that don't have any biology background

1905.04 -> or physiology background,

1906.58 -> just understand that there are two main types of thirst.

1909.97 -> Both types of thirst, osmotic thirst and hypovolemic thirst,

1914.1 -> are not just about seeking water,

1916.26 -> but they also are about seeking salt.

1919.81 -> In very general terms,

1921.81 -> salt, aka sodium, can help retain water.

1926.94 -> Now, that doesn't mean that salt always retains water.

1930.14 -> If you have excessive amounts of salt,

1931.96 -> will you retain excessive amounts of water?

1934.03 -> Well, sort of.

1934.87 -> As we'll soon learn, it's all contextual,

1937.28 -> but for most cases,

1939.95 -> we can say that by having salt in our system,

1943.57 -> our brain and our body can function normally

1945.83 -> provided the levels of salt are adequate

1948.4 -> and not too high or too low,

1950.69 -> and thirst, while we often think of it

1954.11 -> as just a way to bring fluid into our body,

1956.74 -> is designed as a kind of

1959.07 -> a interoceptive perception.

1961.61 -> What I mean by that, interoception, as many of know now

1964.47 -> from listening to this podcast,

1965.55 -> is a paying of attention or a recognition, rather,

1968.94 -> a conscious recognition

1970.08 -> of the events going on within our body,

1972.48 -> so when we are thirsty,

1974.14 -> it's a certain form of interoception.

1976.01 -> We go, "Oh, I need something or I crave something."

1978.63 -> You may not know exactly what you need,

1980.25 -> but when you are thirsty, you're not just seeking water;

1983.53 -> you're also seeking to balance your osmolarity,

1987.04 -> which means you may be seeking salty fluids

1991.77 -> or foods, in some cases.

1993.41 -> You'll try and accomplish this by eating,

1995.52 -> or it may be that you're trying to avoid,

1997.79 -> or you will be inspired to avoid salty fluids and foods,

2001.69 -> but if you want to understand sodium

2004.7 -> and its roles in the body,

2005.81 -> you have to understand thirst,

2006.98 -> and if you want to understand thirst,

2008.27 -> you have to understand how fluid balance

2011.32 -> is regulated in the body.

2012.28 -> That's not surprising at all,

2014.32 -> but sodium and water work together

2017.55 -> in order to generate what we call thirst.

2019.66 -> Sodium water work together in order to either retain water

2023.71 -> or inspire us to let go of water, to urinate,

2026.92 -> so before we can dive into the specifics around salt

2030.49 -> and how to use salt for performance

2032.08 -> and various recommendations and things to avoid,

2035.47 -> we need to drill a little bit deeper

2037.44 -> into this fluid balance mechanism in the body,

2040.037 -> and for that reason,

2041.12 -> we have to pay at least a little bit of attention

2043.13 -> to the kidney.

2044.22 -> The kidney is an incredible organ,

2046.74 -> and one of the reasons the kidney is so amazing

2048.96 -> is that it's responsible for both retaining, holding onto,

2053.08 -> or allowing the release of various substances from the body,

2056.77 -> substances like glucose or amino acids,

2060.5 -> urea, uric acid,

2063.64 -> salt, potassium, magnesium.

2066.17 -> It's basically a filter,

2067.62 -> but it's a very, very intelligent filter.

2071.15 -> I mean, intelligent meaning it doesn't have its own mind,

2073.53 -> but the way it works is really beautiful.

2076.36 -> Basically, blood enters the kidney

2079.52 -> and it goes through a series of tubes

2082.65 -> which are arranged into loops.

2084.35 -> If you want to look more into this,

2085.58 -> there's the beautiful Loop of Henle

2088.18 -> and other aspects of the kidney design

2091.12 -> that allow certain substances to be retained

2095.51 -> and other substances to be released,

2096.97 -> depending on how concentrated those substances are

2099.31 -> in the blood.

2102.23 -> The kidney responds to a number of hormonal signals,

2104.62 -> including vasopressin,

2106.99 -> in order to, for instance, antidiuretic hormone,

2109.25 -> in order to hold onto more fluid

2111.58 -> if that's what your brain and body need,

2115.03 -> and it responds to other hormonal signals as well,

2117.81 -> so it's a pretty complex organ.

2120 -> Nonetheless, there's a key point, which I already mentioned,

2123.62 -> that I think most people don't realize.

2125.33 -> This is actually something

2126.163 -> that I like to tell kids when I meet them,

2127.73 -> provided that they're of appropriate age.

2129.24 -> I'll say, oftentimes, with kids learn that I'm a scientist,

2133.06 -> they'll ask a question about something related to science,

2136.52 -> and hopefully, for my sake,

2138.4 -> it's something about neuroscience,

2140.55 -> but one thing that I'll tell kids,

2141.94 -> I'll say, "Do you know that your urine, your pee,

2145.357 -> "is actually filtered blood?"

2147.21 -> And occasionally, that will really terrify a kid,

2149.52 -> but that also occasionally really terrifies an adult,

2153.03 -> but indeed, your urine is filtered blood.

2155.52 -> Basically, blood gets into the kidney.

2157.19 -> The kidney's going to filter out certain things.

2158.86 -> Certain things are going to be allowed to pass through

2160.32 -> and others are not, okay?

2162.51 -> So the way the kidney is designed is that

2165.24 -> about 90% of the stuff that's absorbed from the blood

2169.53 -> is going to be absorbed early in this series of tubes,

2173.39 -> and only a small percentage

2175.09 -> is going to be regulated or worked out

2177.34 -> as you get into what's called the distal kidney.

2179.34 -> I mean, distal just means the furthest part away, okay?

2183.27 -> The proximal is up close,

2185.54 -> so like your shoulder

2186.373 -> is proximal to your midline of your body,

2188.35 -> and your hand is distal,

2189.89 -> so in biological terms,

2190.93 -> you hear about proximal, distal,

2192.04 -> which just means near or far from,

2194.36 -> so just to give a really simple example,

2196.15 -> let's say that you are very low on fluid.

2199.97 -> You haven't had much to drink in a while.

2201.41 -> Maybe you're walking around on a hot day.

2204.38 -> Chances are that the neurons in your OVLT

2208.16 -> will sense the increase in osmolarity, right?

2211.34 -> The concentration of salt is going to be increased

2214.53 -> relative to the fluid volume that's circulating.

2218.17 -> This, of course, assumes

2219.24 -> that you haven't excreted a lot of sodium

2220.89 -> for one reason or another,

2222.32 -> but that increase in osmolarity is detected by the OVLT.

2225.93 -> The OVLT is going to signal a bunch of different cascades

2229.5 -> through the supraoptic nucleus, et cetera,

2231.61 -> and then, vasopressin is going to be released

2233.73 -> into the bloodstream,

2234.86 -> and vasopressin, again, also called antidiuretic hormone,

2238.38 -> is going to act on the kidney

2240.68 -> and change the kidney's function

2243.55 -> in a couple of different ways,

2244.94 -> some mechanical, some chemical, okay?

2248.24 -> In order to make sure that your kidney

2250.66 -> does not release much water,

2252.93 -> doesn't make you want to urinate,

2255.3 -> and in fact, even if you would try to urinate,

2257.35 -> your body's going to tend to hold onto its fluid stores.

2260.21 -> So very simple, straightforward example.

2263 -> We can also give the other example

2264.4 -> whereby if you are ingesting a lot, a lot, a lot of water,

2267.86 -> and it's not a particularly hot day,

2269.863 -> and you're not sweating very much,

2271.49 -> let's assume your salt intake is constant

2273.49 -> or is low for whatever reason,

2275.79 -> well, then, the osmolarity,

2277.75 -> the salt concentration in your blood,

2279.56 -> is going to be lower.

2280.393 -> Your OVLT will detect that

2282.62 -> because of these osmosensing neurons in your OVLT.

2286.84 -> Your OVLT will fail to signal

2291.09 -> to the supraoptic nucleus,

2293.14 -> and there will not be the release

2294.84 -> of vasopressin antidiuretic hormone,

2296.96 -> and you can excrete all the water

2300.02 -> that your body wants to excrete,

2302.22 -> meaning you'll be able to urinate.

2303.49 -> There's no holding onto water

2304.81 -> at the level of the kidney, okay?

2306.13 -> Very simple examples,

2307.18 -> but hopefully, it illustrates how events within the blood,

2309.88 -> meaning the concentration of salt

2311.2 -> relative to the amount of fluid, right?

2313.58 -> That's what osmolarity is, is detected by the OVLT.

2317.4 -> The brain then communicates to the pituitary.

2319.97 -> The pituitary sends a hormone out into the blood,

2322.15 -> and the hormone acts on the kidney

2324.27 -> to either hold onto or let go of fluid,

2328.43 -> meaning to prevent you from wanting to urinate

2331.09 -> or from stimulating you to want to urinate.

2334.17 -> Very, very simple kind of yes/no-type situation here.

2337.63 -> There's a lot of nuance to this in reality.

2339.56 -> There are a lot of other hormones in this pathway,

2341.14 -> but I think, for at least this stage of the discussion,

2344.14 -> this should be sufficient.

2345.34 -> Some of you may have noticed

2346.93 -> that a molecule we've been talking a lot about today,

2349.38 -> vasopressin, was also mentioned

2351.87 -> on a previous episode of the Huberman Lab Podcast,

2354 -> but in a very different context.

2356.13 -> The molecule I'm referring to is vasopressin,

2358.33 -> and, as I mentioned,

2359.72 -> it's a hormone involved in antidiuresis,

2363.68 -> meaning preventing urination.

2366.26 -> It's an antidiuretic,

2368.19 -> but we also talked about vasopressin

2370.56 -> in the context of desire, love, and attachment.

2373.8 -> We talked about it

2374.633 -> in the context of monogamy and nonmonogamy

2377.17 -> in a species of animal called the prairie vole.

2379.96 -> You can check out that episode.

2381.88 -> I believe vasopressin in the nonmonogamous prairie voles

2385.92 -> are mentioned in the timestamp,

2388.4 -> so it should be easy to find.

2390.6 -> Vasopressin is made

2392.1 -> at multiple locations in the nervous system,

2394.63 -> mainly the supraoptic nucleus,

2396.79 -> and indeed, it's also involved

2399.29 -> in aspects of sexual behavior and mating.

2403.21 -> Now, it does that through mechanisms

2405.74 -> that are distinct from its antidiuretic effects.

2410.52 -> In fact, there are people

2412.76 -> who take vasopressin as an aphrodisiac.

2416.5 -> Now, I'm certainly not suggesting people do that,

2419.13 -> but I have all the confidence in the world

2422.36 -> that the moment I talk about vasopressin,

2423.85 -> someone in the comments is going to say,

2424.957 -> "What do you think about vasopressin nasal sprays

2426.907 -> "and this kind of thing?"

2428.18 -> Vasopressin, and indeed oxytocin,

2430.58 -> another hormone that's involved in pair bonding

2433.87 -> and various aspects of brain and body function,

2436.56 -> are available as nasal sprays

2439.33 -> that can get up into the deep recesses of the brain

2442.28 -> and can impact some of these core

2444.61 -> what we call hypothalamic functions,

2446.13 -> these primitive drives and hypothalamic functions.

2448.6 -> I would encourage a lot of caution,

2451.75 -> maybe even extreme caution in recreational use

2454.52 -> of things like vasopressin and oxytocin

2456.76 -> unless you are working with MD,

2458.73 -> an MD, excuse me,

2459.77 -> and they prescribe it

2460.603 -> or they really know what they're doing.

2461.89 -> These are powerful hormones

2463.64 -> that have a lot of different effects on the brain and body.

2466.54 -> The way that vasopressin, meaning antidiuretic hormone,

2469.9 -> prevents the release of fluid as urine from the body

2473.88 -> is pretty interesting.

2475.11 -> It acts directly on the kidney,

2477.23 -> so, as I mentioned before, blood flows into the kidney.

2479.74 -> A number of things are retained

2481.05 -> in the early part of the kidney.

2482.9 -> Vasopressin acts at a fairly distal,

2485.58 -> meaning kind of end game part

2489.235 -> of the loops of tubes through the kidney,

2492.05 -> and it increases the permeability of those tubes.

2495.47 -> In other words, it makes sure that the fluid

2497.52 -> that would otherwise pass into a collecting duct

2500.35 -> and then go out to the bladder

2501.62 -> never actually makes it to the bladder.

2503.99 -> I point this out because what antidiuretic hormone does is

2507.13 -> it prevents the bladder from filling at all.

2509.15 -> It's not as if it locks fluid in the bladder

2511.39 -> and prevents you from urinating.

2512.89 -> I think the way I've been describing things up until now

2514.787 -> and the way you'll hear about antidiuretic hormone,

2517.04 -> it might sound like it kind of locks up the bladder

2519.38 -> or prevents you from being able to urinate,

2521.25 -> but you have a full bladder.

2522.17 -> That would be very uncomfortable.

2523.22 -> That's not the way it works.

2524.43 -> It actually causes the tubes

2526.74 -> headed towards the bladder from the kidney

2529.34 -> to become permeable,

2530.4 -> meaning to allow fluid to go back into the bloodstream,

2534.38 -> into the rest of the body,

2535.34 -> so that fluid never actually fills the bladder,

2537.27 -> and so you never feel the urge to urinate.

2539.44 -> Now, this is an episode about salt.

2542.25 -> A key thing to understand about the kidney

2543.95 -> is that the kidney uses sodium in order to conserve water,

2548.43 -> which has everything to do with the fact

2550.43 -> that sodium can actually hold water.

2553.96 -> Put differently, water tends to follow sodium,

2557.69 -> so where we have sodium, we tend to have water,

2560.57 -> and sodium, when it's concentrated,

2563.74 -> can hold onto water,

2565.41 -> and that's one of the main ways

2566.81 -> that the kidney holds onto water in the body,

2569.3 -> and as we'll soon learn,

2571.24 -> there is no simple and direct formula to say, for instance,

2574.937 -> "Okay, if salt levels are high, a lot of water is retained,

2579.637 -> "and if salt levels are low, a lot of water is released."

2584.26 -> On the one hand, that can be true,

2586.34 -> but it's also the case

2587.8 -> because these systems are homeostatic,

2589.86 -> meaning they're always seeking balance,

2591.85 -> both within system, within the salt system,

2594.06 -> and between systems, the salt and water system.

2596.97 -> It's also the case, often,

2599.41 -> that if we have enough sodium,

2602.11 -> well, then we can secrete sodium and some water will follow,

2605.98 -> or if we don't have enough sodium, then, yes, indeed

2611.67 -> because we're not holding onto water,

2613.24 -> more fluid can be excreted,

2615.35 -> but if that condition of low sodium lasts long enough,

2619.81 -> then we start to retain water

2621.33 -> because the body recognizes,

2622.567 -> "Ah, salt is low, and water is being excreted,"

2626.15 -> and eventually, a system will kick in to retain water,

2629.35 -> so I'd love to give you

2630.8 -> a simple black-and-white, yes-or-no answer

2633.02 -> for low sodium, high sodium,

2634.46 -> moderate sodium, and water balance,

2636.35 -> but it's all contextual,

2637.92 -> and when I say contextual,

2639.05 -> I mean, it will depend on blood pressure, hypertension,

2642.86 -> prehypertension, if that's there,

2644.79 -> maybe normal tension, hormone levels,

2648.46 -> exercise, et cetera, et cetera.

2650.34 -> A pretty good example of how complicated this can all be

2652.63 -> is one that some of you may be familiar with.

2655.17 -> It's pretty well known

2656.61 -> that during certain phases of the menstrual cycle,

2659.75 -> when estrogen and progesterone

2661.37 -> and other hormones are fluctuating,

2663.15 -> that water can be retained in the body.

2666.44 -> It's what's called edema, or a swelling, sometimes,

2669.51 -> so the common assumption,

2671.6 -> and indeed, it can be true,

2672.86 -> that when estrogen levels are high,

2674.84 -> there's water retention in the body.

2677.69 -> Also, in males, if estrogen levels are high,

2679.83 -> there can be water retention in the body.

2681.28 -> This is one of the reasons why athletes

2684.09 -> and, in particular, bodybuilders

2685.28 -> who take anabolic steroids like testosterone,

2687.48 -> which can be converted into estrogens,

2689.35 -> sometimes they'll look, they'll walk around,

2690.87 -> they look like they were partially inflated.

2692.41 -> They look like they're going to pop,

2693.58 -> and it looks like a swelling of the skin,

2695.7 -> not just because they have large muscles,

2697.16 -> and that's not always, but often, water retention

2700.18 -> due to testosterone conversion into estrogen.

2703.51 -> Now, that all sounds consistent, right?

2705.9 -> Estrogen levels fluctuate in the menstrual cycle.

2708.34 -> In males, where there's an increase in estrogen,

2710.26 -> there's retention of water,

2711.57 -> but actually, estrogen acts as a diuretic,

2714.88 -> so one would think, "Okay, when estrogen levels go up,

2717.267 -> "there should be a lot of fluid excreted,"

2719.24 -> but I bring up this example to point out

2721.32 -> that it's a very complicated and dynamic balance

2723.61 -> between hormones and salt and fluid.

2725.92 -> You can't draw a one-to-one relationship there,

2728.56 -> and that turns out to be a very important point,

2730.8 -> and we can use that,

2732.35 -> not as a way to further complicate things,

2734.47 -> but as a way to understand under which contexts

2739.22 -> less sodium intake or more sodium intake can be beneficial,

2743.3 -> so that's where I'd like to turn our attention now,

2745.29 -> so how much salt do we need?

2747.12 -> And what can we trust

2748.69 -> in terms of trying to guide our ingestion of salt?

2753.21 -> First of all, I want to be very, very clear

2755.37 -> that there are a number of people out there

2757.56 -> that have prehypertension or hypertension.

2760.55 -> You need to know

2761.383 -> if you have prehypertension or hypertension.

2763.54 -> You need to know if you have normal tension,

2766.21 -> meaning normal blood pressure.

2767.91 -> Everyone should know their blood pressure.

2770.147 -> It's a absolutely crucial measurement

2772.55 -> that has a lot of impact

2774.44 -> on your immediate and long-term health outcomes.

2777.4 -> It informs a lot about what you should do.

2779.47 -> Should you be doing more cardiovascular exercise?

2781.62 -> Should you be ingesting more or less salt?

2784.28 -> Should you be adjusting

2785.33 -> any number of different lifestyle factors?

2787.36 -> So you need to know that,

2788.78 -> and without knowing what your blood pressure is,

2791.37 -> I can't give a one-size-fits-all recommendation,

2794.45 -> and indeed, I'm not going to give medical recommendations.

2796.85 -> I'm simply going to spell out what I know about the research,

2799.96 -> which, hopefully, will point you in the direction

2801.35 -> of figuring out what's right for you

2802.99 -> in terms of salt and indeed fluid intake.

2805.54 -> There is a school of thought

2807.03 -> that everybody is consuming too much salt,

2810.42 -> and I do want to highlight the fact

2812.52 -> that there are dozens, if not hundreds, of quality papers

2816.49 -> that point to the fact that a, quote-unquote, high salt diet

2821.51 -> can be bad for various organs and tissues in the body,

2825.54 -> including the brain.

2827.85 -> It just so happens that because fluid balance,

2831.56 -> both inside and outside of cells,

2833.35 -> is crucial, not just for your heart and for your lungs

2836.89 -> and for your liver and for all the organs of your body,

2839.34 -> but also for your brain,

2840.85 -> that if the salt concentration

2843.3 -> inside of cells in your brain

2846.19 -> becomes too high, neurons suffer, right?

2849.77 -> They will draw fluid into those cells

2852.08 -> because water tends to follow salt, as I mentioned before,

2856.3 -> and those cells can swell.

2858.97 -> You can literally get swelling of brain tissue.

2861.22 -> Conversely, if salt levels are too low

2864.15 -> inside of cells in any tissue of the body,

2866.9 -> but in the brain included,

2870.03 -> then the cells of the body and brain can shrink

2874.87 -> because water is pulled into the extracellular space,

2879.36 -> away from cells,

2880.62 -> and indeed, under those conditions,

2883.09 -> brain function can suffer,

2885.31 -> and indeed, the overall health of the brain can suffer,

2888.06 -> so there are many reports out there

2890.88 -> indicating, both in experimental models

2893.75 -> and, to some extent, in humans,

2895.41 -> that overconsumption of salt

2897.24 -> is bad for brain function and longevity,

2899.76 -> and yet there is also decent evidence,

2903.04 -> in both animal models and humans,

2905.05 -> that if salt consumption is too low,

2908.24 -> then brain health and longevity will suffer,

2911.27 -> as will other organs and tissues of the body,

2913.93 -> so, like most things in biology,

2915.42 -> you don't want things too high or too low.

2918.73 -> Now, I would say that the vast majority of studies out there

2922.14 -> point to the fact that a high-salt diet

2925.47 -> is detrimental to brain health and function.

2928.54 -> Most of the studies have focused on that aspect

2932.11 -> of salt balance and its consequences on brain function.

2937.28 -> One critical issue with many of those studies, however,

2940.97 -> is that the high-salt diet

2943.1 -> is often coupled to other elements of diet

2946.28 -> that are also unhealthy,

2947.87 -> things like excessively high levels of carbohydrates or fats

2951.41 -> or combinations of carbohydrates and fats,

2954.06 -> and so while I know

2955.26 -> there are many burning questions out there

2956.97 -> about how much salt one needs

2958.86 -> if they are on a low-carbohydrate diet

2960.96 -> or if they are fasting or if they are on a vegan diet,

2964.31 -> there have simply not been many studies

2966.9 -> that have explored the low, moderate,

2969.52 -> and high-salt conditions

2971.47 -> on a backdrop of very controlled nutrition,

2974.33 -> and that's probably reflective of the fact

2976.43 -> that there are not a lot

2978.03 -> of very well-controlled nutrition studies out there.

2980.25 -> There are some, of course,

2982 -> but it's very hard to get people to adhere

2984.12 -> to nutritional plans in a very strict way,

2986.43 -> and to do that for sufficient periods of time

2988.693 -> that would allow the various health outcomes to occur.

2992.64 -> Nonetheless, there's some interesting reports

2995.41 -> that indicate that the amount of salt intake

2999.88 -> can indeed predict health outcomes

3003.4 -> or what we call hazardous events,

3006.38 -> things like cardiovascular events and stroke and so forth,

3009.26 -> and what's interesting is that indeed a lower,

3013.79 -> I'm not saying low, right?

3015.033 -> Because I don't believe that you want your diet

3016.83 -> to be truly low in anything except, perhaps, poison,

3021.08 -> but a lower-salt diet can reduce

3025.86 -> the number of these so-called hazardous events,

3028.7 -> but it's a somewhat of a shallow U-shaped function

3032.98 -> such that, yes indeed, a high salt intake

3037.97 -> can be very detrimental for your health,

3040.94 -> both in terms of cardiovascular events, stroke,

3043.44 -> and other deleterious health events,

3046.24 -> but somewhere in the middle

3048.21 -> that actually sits quite to the right,

3051.26 -> meaning higher than what is typically recommended

3054.43 -> for salt intake,

3055.83 -> can actually reduce the number of these hazardous events,

3058.79 -> at least some reports point to that,

3060.93 -> and so I want to emphasize

3062.17 -> what one of those particular reports says,

3065.67 -> and I also want to be sure to counter it

3067.58 -> from the perspective of the context

3069.493 -> that that study was set in

3070.9 -> because, again, my goal here

3072.27 -> is not to give you a strict set of recommendations at all.

3075.873 -> It's to point you to the literature,

3078.08 -> try and make that literature as clear as possible,

3079.94 -> and allow you to evaluate for yourself,

3081.97 -> and I don't just say that to protect us.

3083.65 -> I say that to protect you

3084.98 -> because indeed you are responsible

3086.77 -> for your health and your health choices,

3088.61 -> so the paper that I'm referring to

3090.353 -> is a very interesting one.

3092.37 -> We, of course, never want to put too much weight

3094.97 -> on any one report,

3096.38 -> but this is a paper that was published in 2011

3099.42 -> in the "Journal of the American Medical Association."

3101.94 -> The title of the paper is

3103.277 -> "Urinary Sodium and Potassium Excretion

3105.917 -> "and the Risk of Cardiovascular Events."

3108.07 -> We have not talked much about potassium yet,

3110.5 -> but sodium and potassium tend to work in concert

3113.62 -> in the brain and body

3114.79 -> in order to regulate

3115.85 -> various physiological functions in health,

3117.6 -> and we'll talk more about potassium as time goes on.

3120.39 -> The key plot or set of data in this study,

3125.395 -> for those of you that want to look it up, we will link to it.

3128.49 -> There are a lot of data in here, but is Figure 1,

3131.26 -> which is basically evaluating

3134.24 -> the amount of urinary excretion of sodium,

3137.3 -> which is a somewhat indirect,

3139.41 -> but nonetheless valuable measure

3141.23 -> of how much sodium people were ingesting

3144.33 -> and plotted against that is what they call the hazard ratio,

3148.27 -> and the hazard ratio points to

3151.3 -> the composite of cardiovascular death, stroke,

3153.56 -> myocardial infarction, and an infarct is an injury,

3156.97 -> and hospitalization for congestive heart failure,

3159.9 -> and what it points to is the fact

3161.73 -> that the hazard ratio is low-ish

3165.82 -> at sodium excretion of about 2 grams per day,

3169.78 -> but then continues to go down

3172.97 -> until about 4.5

3176.57 -> to 5 grams per day

3178.15 -> that, remember, this is sodium excretion,

3179.88 -> so it's reflective of how much sodium was in the body,

3182.89 -> which is reflective of how much sodium was ingested,

3185.17 -> and then, the hazard ratio increases fairly dramatically,

3189.12 -> a very steep slope,

3190.85 -> heading anywhere from 7 to 8 to 10

3194.54 -> and out towards 12 grams of sodium excretion per day,

3198.17 -> so the simplest way to interpret these data

3200.65 -> are that at fairly low levels of sodium,

3204.85 -> meaning at about 2 grams per day,

3207.69 -> you run fewer health risks,

3209.95 -> but the number of risks continues to decline

3211.9 -> as you move towards 4 and 5 grams per day,

3214.56 -> and then, as you increase your salt intake further,

3217.62 -> then, the risk dramatically increases,

3220.89 -> so no study is holy,

3222.13 -> nor is any figure in any study

3224.82 -> or any collection of studies holy.

3227.79 -> Rather, we always want to look

3229.02 -> at what the bulk of data in a particular field reveal.

3232.69 -> Nonetheless, I think the plot that we described,

3234.93 -> meaning the graph that we described,

3236.46 -> is pretty interesting

3237.57 -> in light of the 2020 to 2025

3241.95 -> dietary recommendations for Americans,

3243.74 -> which is that people consume no more than 2.3 grams,

3248.8 -> meaning 2,300 milligrams of sodium per day.

3252.5 -> That's about 1/2 a teaspoon

3255.19 -> of salt per day.

3257.96 -> Now, most people are probably consuming more than that

3262.36 -> because of the fact that they are ingesting processed foods,

3266.42 -> and processed foods tend to have more salt in them

3269.68 -> than nonprocessed foods.

3270.82 -> Now, of course, that's not always the case, right?

3273.05 -> Sea salt is not a processed food, in most cases,

3276.4 -> and there are a lot of unprocessed foods

3279.15 -> that can be high in sodium,

3281.09 -> but processed foods, in particular,

3282.83 -> tend to have a lot of sodium.

3283.83 -> You can see this simply by looking at the packaging

3286.41 -> of any number of different foods,

3288.11 -> but if we are to take this number of 2.3 grams,

3292.88 -> that's the recommended cutoff for ingestion of sodium,

3297.44 -> it actually falls in a portion of the curve

3301.11 -> that we were talking about a moment ago

3302.82 -> that indeed is associated with low hazard,

3307.71 -> low incidence of hazardous outcomes,

3309.57 -> cardiovascular event, stroke, et cetera,

3311.78 -> but the ingest, according to that plot,

3315.37 -> the ingestion of 4 or 5 grams of sodium,

3319.42 -> almost double,

3320.63 -> or more sodium than is currently recommended,

3324.49 -> is associated with even lower numbers of hazardous events,

3329.33 -> so we need to think about this,

3330.69 -> and we need to explore it

3331.84 -> in the context of other studies, of course,

3334.52 -> and we need to evaluate it in terms of this thing

3337.95 -> that we've been going back to again and again,

3340.4 -> which is context, right?

3342.4 -> These recommendations of 2.3 gram per day cutoff

3346.57 -> is in the context of a landscape where some people

3349.53 -> do indeed have hypertension or prehypertension.

3353.45 -> The incidence of hypertension has gone up dramatically

3355.8 -> in the last 100 years

3357.45 -> and seems to continue to go up.

3360.12 -> Whether or not that's because of increased salt intake

3364.6 -> or whether or not it's because of increased salt intake

3367.33 -> and other things such as highly processed foods,

3370.43 -> that isn't clear,

3371.3 -> again, pointing to the challenge

3373.16 -> in doing these epidemiological studies

3374.92 -> and really parsing what aspects

3377.29 -> of a change in some health metric is due to, for instance,

3380.92 -> the ingestion of more sugars versus more salts

3383.12 -> or simply because of the ingestion of more salts.

3385.76 -> It's a complicated, almost barbed-wire topic by now,

3389.43 -> but we can start to pull apart that barbed wire tangle

3392.55 -> and start to evaluate some of the other people

3395.377 -> and other conditions that exist out there, maybe for you,

3400.56 -> that actually warrant more sodium intake

3403.79 -> and where more sodium intake might actually be beneficial,

3406.72 -> so, again, I want to be very, very clear

3408.63 -> that you need to know your blood pressure.

3410.14 -> If you have high blood pressure or you're prehypertensive,

3412.86 -> you should be especially cautious

3414.46 -> about doing anything that increases your blood pressure,

3417.18 -> and, as always, you want to, of course, talk to your doctor

3419.41 -> about doing anything

3420.243 -> that could adjust your health in any direction,

3422.7 -> but nonetheless, there are some important papers

3425.74 -> that have been published in recent years.

3428.23 -> I want to point to one of them, in particular.

3430.15 -> This is a paper that was published

3432.39 -> in the journal "Autonomic Neuroscience: Basic and Clinical"

3435.99 -> because this paper, like several other papers,

3439.52 -> asked the question,

3440.61 -> and indeed, they ask the question in the title.

3442.43 -> It's a review: "Dietary Sodium and Health:

3444.547 -> "How Much Is Too Much for Those with Orthostatic Disorders."

3448.69 -> Now, orthostatic disorders

3450.23 -> come in a bunch of different varieties,

3451.54 -> and we're going to talk about those in a moment,

3453.49 -> but there are a number of people out there

3455.29 -> that have low blood pressure, right?

3457.42 -> People that get dizzy when they stand up,

3460.01 -> people that are feeling chronically fatigued,

3462.82 -> and in some cases, not all,

3465 -> those groups can actually benefit

3466.56 -> from increasing their sodium intake.

3468.67 -> Several episodes ago on the Huberman Lab Podcast,

3471.26 -> I gave a, what, it's just clearly what we call anec-data,

3475.07 -> which is not even really data.

3476.33 -> It's just anecdotal data of an individual

3480.47 -> who was always feeling hungry and craving sugar,

3483.63 -> and based on the fact that they also had low blood pressure,

3487.52 -> I had them talk to a physician,

3489.09 -> and they got permission

3490.13 -> to try a little mini-experiment on themselves,

3493.02 -> and so they did, and that mini-experiment was

3495.06 -> anytime they felt like they were craving sugar

3497.69 -> or they were feeling a little lightheaded and dizzy,

3499.44 -> rather than reaching for something with caloric intake,

3502.19 -> they took a little bit of sea salt,

3503.47 -> a little pinch of sea salt,

3505.07 -> and put it into some water, and drank it,

3507.46 -> or, in the case of this individual,

3509.68 -> they would actually take a little sea salt packet,

3511.3 -> and they would actually just down a sea salt packet,

3513.09 -> and for them, that provided tremendous relief

3515.76 -> for their dizziness,

3517.66 -> but that, of course, was in the context

3519.3 -> of somewhat abnormally low blood pressure,

3522.72 -> so I don't think that they are alone

3524.64 -> in the fact that many people out there

3526.47 -> suffer from a low blood pressure condition.

3530.09 -> Many people out there

3531.03 -> suffer from a high blood pressure condition,

3532.75 -> so know your blood pressure,

3533.92 -> and understand that blood pressure, in part,

3536.85 -> is regulated by your sodium intake and your sodium balance.

3540.73 -> Why?

3541.563 -> Well, because of the osmolarity of blood

3543.88 -> that we talked about before,

3545.38 -> where if you have a certain concentration of sodium,

3549.9 -> meaning sufficient sodium in your bloodstream,

3552.17 -> that will tend to draw water into the bloodstream,

3554.02 -> and essentially,

3554.853 -> the pipes that are your capillaries, arteries, and veins

3557.62 -> will be full.

3558.63 -> The blood pressure will get up to your head,

3560.55 -> whereas some people, their blood pressure is low

3562.9 -> because the osmolarity of their blood is low,

3566.07 -> and that can have a number of downstream consequences.

3568.96 -> I should also mention it can be the consequence itself

3572.41 -> of challenges or even deficits in kidney function,

3577.14 -> but all of these organs are working together,

3579.37 -> so the encouragement here

3581.1 -> is not necessarily to ingest more sodium.

3582.753 -> It's to know your blood pressure

3584.24 -> and to address whether or not an increase in sodium intake

3587.89 -> would actually benefit your blood pressure

3590.11 -> in a way that could relieve some of the dizziness

3592.72 -> and other symptoms of things like orthostatic disorders,

3597.76 -> but, of course, to do that in a safe context

3599.81 -> and to never play games

3600.92 -> with your blood sugar or your blood osmolarity

3603.36 -> that could set your system

3604.38 -> down a cascade of negative events.

3607.17 -> Let's look at what the current recommendations are

3610.01 -> for people that suffer from orthostatic disorders

3613.02 -> like orthostatic hypo, meaning too low, tension,

3616 -> orthostatic hypotension, postural tachycardia syndrome,

3619.133 -> sometimes referred to as POTS, P-O-T-S,

3623.27 -> or idiopathic orthostatic tachycardia and syncope.

3626.85 -> These have the incredibly elaborate names.

3629.96 -> Those groups are often told to increase their salt intake

3633.25 -> in order to combat their symptoms.

3634.75 -> The American Society of Hypertension

3636.72 -> recommends anywhere from 6,000 to 10,000.

3641.31 -> These are very high levels,

3642.51 -> so this is 6 grams to 10 grams of salt per day,

3645.87 -> keeping in mind, again,

3647.47 -> that salt is not the same as sodium,

3650.92 -> so that equates

3651.753 -> to about 2,400 to 4,000 milligrams of sodium per day.

3655.97 -> Again, if you want to learn more about this

3657.78 -> and get more of the citations,

3659.19 -> I'll refer you back to this study

3661.13 -> on "Dietary Sodium and Health:

3662.427 -> "How Much Is Too Much for Those with Orthostatic Disorders."

3664.84 -> We'll put a link to this in the caption show notes,

3667.77 -> so that's not just in the U.S.

3670.71 -> The salt recommendations

3671.7 -> from the Canadian Cardiovascular Society

3673.7 -> are 10,000 milligrams of salt per day,

3676.01 -> so 4 grams of sodium is what that equates to,

3679.16 -> and on and on and on,

3680.41 -> for things like POTS,

3682.53 -> for these postural syndromes that result from,

3685.33 -> or I should say from these syndromes

3687.12 -> that involve low blood pressure

3689.11 -> when people stand up or in certain postures,

3691.55 -> so I point out this paper,

3693.84 -> and I point out these higher salt recommendations

3696.85 -> to emphasize, again, that context is vital, right?

3700.82 -> That people with high blood pressure

3702.25 -> are going to need certain amounts of salt intake.

3704.9 -> People with lower blood pressure,

3707.33 -> and maybe with some of these postural orthostatic syndromes,

3710.76 -> are going to need higher amounts of salt,

3713.18 -> and for most people out there,

3715.7 -> you're going to need to evaluate how much salt intake

3718.22 -> is going to allow your brain and body to function optimally,

3721 -> and there are some fairly straightforward ways

3723.68 -> to explore that,

3724.56 -> and there's some ways to explore that

3726.26 -> in the context of what you already know

3728.25 -> about thirst and salt appetite

3730.72 -> that can make that exploration

3732.6 -> one in which it's not going to be

3734.07 -> a constant wandering around in the dark

3736.03 -> and where you can figure out what's right for you.

3738.28 -> For most people, a moderate increase in salt intake

3741.56 -> is not going to be detrimental

3743.08 -> provided that you consume enough fluids,

3746.31 -> in particular, water, 'kay?

3748.85 -> Meaning if you happen to overeat salt a bit,

3751.15 -> you will get thirsty, you will ingest more water,

3754.49 -> and you will excrete the excess sodium.

3757.94 -> There is evidence

3758.773 -> that the body can store sodium in various organs.

3762.58 -> That storage of sodium

3764.13 -> may or may not be a detrimental thing.

3767.3 -> In general, excess storage of sodium

3769.9 -> in tissues and organs of the brain and body

3771.91 -> is not thought to be good for long-term health,

3775.78 -> so eating much more sodium than you need

3779.02 -> for long periods of time is indeed bad for you.

3783.56 -> Earlier, I mentioned that salt

3786.3 -> and your hunger and thirst for salt

3788.72 -> is homeostatically regulated,

3791.04 -> and indeed, that's the case,

3791.95 -> much like temperature is homeostatically regulated.

3795.03 -> What that means is, if you pay attention to it,

3799.39 -> if your salt levels are low,

3801.93 -> you will tend to crave salt

3803.76 -> and salty beverages and salty foods,

3807.15 -> and in most cases, you should probably follow that craving

3810.73 -> provided those salty beverages and salty foods

3813.07 -> are not bringing in a lot of other things

3816.2 -> or anything, ideally, that's bad for you,

3818.9 -> so I think it's fair to say

3820.88 -> that whether or not you're vegan, vegetarian,

3823.01 -> carnivore, omnivore,

3824.64 -> that we should all try to limit our ingestion

3829.32 -> of processed foods, a'ight?

3831.55 -> My read of the literature is that, sure,

3833.97 -> some processed foods are acceptable for us

3836.7 -> and aren't going to kill us outright,

3838.73 -> but that for most people in the world,

3840.87 -> eating fewer processed foods

3842.38 -> is just going to be a good thing to do,

3844.79 -> so following your salt hunger and thirst,

3848.48 -> in most cases, is going to be beneficial

3852.18 -> provided that it's in the context

3854.43 -> of eating healthy, nonprocessed foods on whatever backdrop

3858.52 -> of nutritional and dietary recommendations is right for you.

3861.21 -> I simply can't tell you what to eat and what not to eat

3865.49 -> because I acknowledge the fact that some people are vegans

3869.65 -> because of ethical reasons related to animals,

3873.29 -> or some people are vegans because of reasons

3876.97 -> related to the climate and the environment.

3880.06 -> Other people do it for specific health reasons.

3883.79 -> Likewise, I know plenty of people

3885.54 -> that eat meat and avoid vegetables, believe it or not,

3888.39 -> and I know people that eat both,

3889.84 -> and they do this, often,

3891.91 -> each, I should say, all,

3893.62 -> citing literature that supports their particular camp

3896.11 -> and their particular view.

3897.41 -> It's not a territory I want to get into,

3899.9 -> but with respect to salt intake

3901.6 -> and the fact that salt intake is homeostatically regulated,

3906.83 -> it is the case that if you're craving salt,

3909.13 -> you probably need it,

3910.81 -> so for those of you that are sweating excessively,

3913.11 -> or even if you're in a very hot environment,

3916.41 -> and you're not exercising, and you're just losing,

3919.46 -> you're losing water and salt from your system,

3922.12 -> remember, also, that you can be in a very cold environment,

3924.61 -> very cold, dry environments often go together,

3927.76 -> and you can be losing a lot of fluids from your body,

3930.29 -> and you will crave fluids and salt even though it's cold

3932.89 -> and you're not actually noticeably perspiring,

3936.84 -> so if you're exercising a lot,

3938.48 -> if you're in a particular cold, dry environment

3940.84 -> or a particular hot environment,

3942.5 -> you ought to be ingesting

3943.83 -> sufficient amounts of salt and fluid.

3946.49 -> A rule of thumb for exercise-based replenishment of fluid

3951 -> comes from what I, some episodes back,

3954.02 -> referred to as the Galpin equation.

3956.7 -> The Galpin equation, I named it after Andy Galpin,

3960.4 -> and I think that is the appropriate attribution there.

3963.26 -> Andy Galpin is an exercise physiologist

3966.58 -> at Cal State, Fullerton, I believe,

3969.56 -> and he's going to be a podcast guest

3971.84 -> here on the Huberman Lab Podcast.

3973.18 -> He's an exceptional muscle physiologist.

3975.08 -> He also lives in the practical realm

3977.01 -> where he gives recommendations about exercise

3980.81 -> to expert athletes as well as the everyday person,

3984.32 -> so the Galpin equation is based on the fact

3986.44 -> that we lose about one to five pounds of water per hour,

3991.1 -> which can definitely impact our mental capacity

3994.12 -> and our physical performance,

3995.97 -> and the reason that loss of water from our system

3999.62 -> impacts mental capacity and physical performance

4001.83 -> has a lot to do with, literally,

4004.59 -> the changes in the volume of those cells,

4006.7 -> the size of those cells,

4007.93 -> based on how much sodium is contained

4009.45 -> in or outside those cells,

4010.84 -> and something that I've alluded to before on the podcast,

4013.67 -> and I'll talk about more in a moment,

4015.75 -> which is that neurons signal to one another

4019.1 -> by way of electricity

4020.68 -> through something called the action potential,

4022.18 -> and that actually requires sodium

4024.15 -> and potassium and magnesium,

4026.08 -> so the Galpin equation suggests that we start exercise

4028.86 -> hydrated with electrolytes, not just with water,

4032.29 -> so that means water

4033.53 -> that has some sodium, potassium, and magnesium.

4038.24 -> There are simple, low-cost ways to do that we'll talk about,

4041.46 -> and the formula for hydration,

4043.93 -> the so-called Galpin equation,

4045.13 -> is your body weight in pounds divided by 30

4050.22 -> equals the ounces of fluid you should drink

4052.33 -> every 15 minutes.

4054.22 -> That may turn out to be more fluid

4056.34 -> than you can comfortably consume

4057.97 -> during the activity that you're performing.

4059.9 -> Now, the Galpin equation

4062.38 -> is mainly designed for exercise,

4065.32 -> but I think is actually a very good rule of thumb

4069.11 -> for any time that you need to engage mental capacity,

4072.29 -> not just physical performance.

4075.58 -> Your body weight in pounds divided by 30

4077.69 -> equals the ounces of fluid you should drink

4080.01 -> every 15 minutes

4080.95 -> does not necessarily mean you have to ingest it

4083.48 -> every 15 minutes on the dot,

4086.27 -> and I think many activities, physical activities,

4090.5 -> but also cognitive activities

4092.48 -> like Zoom meetings or in-person meetings

4096.42 -> or lecturing or running or cycling

4100.71 -> are going to make it complicated

4103.37 -> to ingest the appropriate amount of fluid

4105.69 -> every 15 minutes on the dot.

4107.89 -> I'm not going to speak for Andy, for Dr. Galpin,

4110.8 -> but I think he would probably agree

4112.77 -> that these are averages to shoot for,

4115.99 -> and that unless you're hyperneurotic,

4118.71 -> the idea is to make sure that you're entering the activity,

4122.07 -> cognitive or physical, sufficiently hydrated,

4126.16 -> and that throughout that activity,

4127.7 -> you're hydrating regularly,

4128.84 -> and it points to the fact

4130.16 -> that most people are probably underhydrating,

4133.19 -> but not just underhydrating

4135.08 -> from the perspective of not ingesting enough water,

4138.02 -> that they're probably not getting

4139.23 -> enough electrolytes as well:

4141.11 -> sodium, potassium, and magnesium,

4143.47 -> so I've said two somewhat contradictory things.

4145.82 -> On the one hand, I've said, "Follow your salt appetite.

4149.947 -> "Follow your salt thirst.

4150.977 -> "If you're craving salt,

4152.807 -> "ingest some salt until you stop craving the salt."

4156.3 -> On the other hand,

4157.37 -> I've given you this fairly specific recommendation

4161.5 -> based on the Galpin equation

4163.73 -> that you should ingest your body weight in pounds

4165.76 -> divided by 30.

4166.9 -> That's how many ounces of fluid you should drink

4168.48 -> every 15 minutes,

4169.68 -> which I'm guessing, for most people,

4171.09 -> is going to be more fluid

4172.03 -> than they're currently drinking, on average,

4174.37 -> and so how could it be

4175.77 -> that you can have a recommendation for what's optimal

4178.07 -> that's different than the amount

4180.74 -> that you would reflexively drink?

4182.05 -> And it has to do with the fact

4183.44 -> that a lot of the hormone systems

4185.7 -> like vasopressin antidiuretic hormone,

4188.51 -> other hormones like aldosterone,

4190.21 -> and a lot of the neural and hormonal signals

4193.55 -> that govern salt and water balance

4195.75 -> are fairly slow to kick in,

4198.06 -> so, for instance, if you eat a fairly salty meal,

4201.55 -> and you sense that salt,

4203.15 -> you'll probably, meaning you detect it and perceive it

4205.94 -> because the food tastes salty,

4207.49 -> you'll probably want to drink

4209.11 -> a fair amount of fluid with it,

4210.54 -> whereas if some of the salt is disguised by other flavors,

4213.73 -> something that we'll talk about in a few minutes

4215.11 -> when we talk about the neural representation

4217.33 -> of things like salty and sweet,

4220.25 -> well, then, you might not notice that something's salty,

4222.71 -> and then, a few minutes or hours after ingesting that meal,

4226.26 -> you might feel very, very tired.

4227.82 -> You might even wonder

4229.03 -> whether or not it's because of some blood sugar effect.

4232.55 -> Maybe it's a crash in blood sugar, you might think,

4235.06 -> or something else related to that meal,

4236.7 -> or maybe you think

4237.533 -> it's because of some other event in your life,

4239.87 -> but actually, what has happened is you're dehydrated

4243.08 -> because you didn't recognize

4244.21 -> that you needed to drink more fluids,

4246.11 -> so I want to acknowledge the contradiction

4250.12 -> in the idea that everything is homeostatically regulated,

4252.79 -> and therefore you are aware of what you need,

4255.82 -> and the counterargument that,

4258.52 -> ah, you need to follow these strict recommendations

4260.48 -> is actually going to be somewhere in between,

4262.6 -> and, of course, your body and brain can start to adapt

4264.59 -> to certain levels of salt intake.

4266.45 -> There's now a fairly famous study

4269.97 -> that was done in Germany

4272.35 -> which looked at different phases of salt intake,

4276.84 -> meaning they had subjects ingest

4279.9 -> either 12 grams of salt per day or 9 grams per day

4282.61 -> or 6 grams per day for fairly long periods of time,

4286.27 -> and they collected urine for testing.

4288.41 -> This was actually a very controlled study.

4290.21 -> I'm just going to paraphrase

4291.27 -> from the National Institutes of Health report on this study

4295.26 -> because they did a very nice write-up of it,

4297.96 -> and they say that a big surprise of these results

4301.43 -> is that whatever the level of salt that was consumed,

4304.47 -> sodium was stored and released from the subjects' bodies

4308.67 -> in fairly regular weekly and monthly patterns,

4312.46 -> meaning people tended to adapt

4313.89 -> to a certain level of salt intake,

4315.86 -> and then it led to a fairly constant amount

4319.33 -> of salt retention and urine fluid excretion,

4323.4 -> and that's because of the various hormones,

4325.8 -> like aldosterone,

4326.7 -> which regulates sodium excretion from the kidney,

4328.73 -> and glucocorticoids,

4329.96 -> which we'll talk about more in a moment,

4331.44 -> which help regulate metabolism.

4333.08 -> Glucocorticoids are released from the adrenal glands,

4336.04 -> which ride atop the kidneys,

4337.85 -> and there's a very close relationship

4339.38 -> between the stress system glucocorticoids

4342.11 -> and the salt system,

4343.68 -> so the reason why your salt appetite

4347.41 -> isn't a perfect readout of how much salt you should ingest

4350.72 -> and why it might be helpful to follow some of these formulas

4353.18 -> like the Galpin equation,

4354.26 -> especially if you're engaging in exercise

4357.02 -> where you're going to be perspiring, of course,

4359.56 -> is that your body will tend to adapt

4361.89 -> to a certain amount of salt intake over time,

4363.68 -> and then, your appetite for salt

4365.21 -> won't necessarily be the best indication

4367.56 -> of how much salt you should ingest or avoid.

4371.67 -> Before I move on,

4372.72 -> I want to really reemphasize the fact

4375.41 -> that inside of the Galpin equation

4377.83 -> there is that mention of every 15 minutes,

4380.32 -> and people have come back to me again and again about this

4382.96 -> saying, "I can't drink that much water every 15 minutes.

4385.267 -> "It's too much volume of fluid in my stomach.

4388.127 -> "I can't run with that," et cetera.

4389.43 -> Remember, these are averages,

4391.79 -> so that's what you want to average

4393.31 -> around a particular activity.

4394.66 -> These not strict recommendations where a buzzer goes off

4396.98 -> and every 15 minutes you have to chug

4398.44 -> that exact amount of electrolyte-containing solution.

4401.33 -> Another key feature of the study

4404.231 -> that I was referring to before,

4406.05 -> which, incidentally,

4407.05 -> was published in the "Journal of Clinical Investigation,"

4409.41 -> is that the body regulates its salt and water balance,

4412.86 -> not just by excreting sodium, right?

4415.6 -> But by retaining or releasing water,

4418.18 -> and this is because of the relationship

4419.51 -> between sodium and water that we were talking about before,

4422.22 -> and the advantage of this mechanism, they state,

4424.66 -> here I'm paraphrasing,

4425.84 -> is that the long-term maintenance of body fluids

4428.27 -> is dependent, is not as dependent on external water

4431.95 -> as once believed, right?

4433.21 -> What this system probably evolved to do

4435.56 -> was to adjust to different levels of sodium availability

4438.45 -> in the environment,

4439.67 -> and that raises a really key element

4442.64 -> of salt and its importance in human history

4446.31 -> and human evolution and human health.

4448.46 -> Haven't talked too much about this,

4449.64 -> and there are several very good books

4452.32 -> about the history of salt.

4453.93 -> Salt was a very valuable

4457.2 -> and heavily sought-after substance

4459.67 -> throughout much of human history,

4461.65 -> so much so that there are actually written reports

4464.88 -> of people being paid for labor in the form of salt,

4468.72 -> and salt, when it's scarce,

4472.008 -> has been quite expensive in certain regions of the world,

4474.98 -> especially regions located further away from the sea,

4478.46 -> and a friend of mine

4479.74 -> who has deep roots within the culinary community

4483.38 -> told me about traveling

4486.421 -> to some somewhat impoverished areas of Europe some years ago

4490.68 -> and going into homes where

4493.04 -> in the middle of the kitchen table, there was a fish,

4496.84 -> a salty fish hanging from a thread

4500.67 -> above the table,

4502 -> and that because of a lack of availability of table salt,

4505.46 -> the common practice was to take any food

4507.85 -> that needed some salt for additional flavoring

4510.06 -> and to actually rub that food on this salty fish

4513.24 -> or to squeeze the fish a bit onto the food substance

4517.48 -> in order to get salt from it,

4519.23 -> so that's a very kind of extreme example.

4522.68 -> Nowadays, we kind of take salt for granted,

4524.54 -> and most of the discussion out there is about excess salt,

4527.67 -> but, as I'm pointing out, that salt, for a long time,

4531.25 -> has been a very sought-after commodity

4534.49 -> and one that people really cherished for their health.

4538.22 -> In the episode that I did on metabolism,

4540.68 -> I talked about the relationship between salt and iodine.

4543.36 -> If you're interested in iodine

4545.03 -> and whether or not iodized salt or noniodized salt

4547.43 -> is best or required,

4549.53 -> I'd encourage you to listen to that episode,

4551.33 -> which was about, again, metabolism.

4553.67 -> Some people may need more iodine intake.

4556.02 -> Some people perhaps do not.

4557.37 -> Some people might even want to ingest things like kelp.

4559.68 -> Some people might not,

4560.97 -> so please listen to that episode

4562.56 -> if you're interested in the iodine aspects of salt,

4565.06 -> which have direct impact

4566.61 -> on thyroid hormone and thyroid function,

4568.91 -> which, of course, relates to metabolism.

4571.87 -> Nowadays. there's a lot of interest in

4573.75 -> and even a kind of proliferation of what I call fancy salts,

4577.18 -> so whether or not you should be ingesting sea salts

4579.32 -> or common, whether or not common table salt will suffice.

4583.64 -> In most cases, for what we're discussing here,

4586.31 -> common table salt is fine,

4588.63 -> but I should point out that sea salt

4590.54 -> often contains other minerals, which can be very useful,

4593.33 -> and we will do entire episodes on those other minerals,

4595.76 -> so sea salt can contain

4598.88 -> dozens or more of minerals,

4600.68 -> some of which can be quite valuable to our health,

4603.72 -> others of which are less important

4606.04 -> and only need to be consumed in trace amounts,

4608.01 -> but you're not going to get many minerals, if any,

4610.79 -> from common table salt,

4612.35 -> and that's why, in addition to the pretty colors,

4615.27 -> and, perhaps, some people report

4617.05 -> that they actually taste better,

4619.11 -> some of these so-called fancy salts or sea salts,

4621.96 -> you might want to consume

4623.16 -> a more advanced form of salt, if you will,

4626.21 -> although I suppose

4627.043 -> it's actually the more primitive form of salt

4628.62 -> if it's actually the one that comes from the ocean,

4630.62 -> so we've all heard about how excess salt,

4632.55 -> it's bad for blood pressure,

4634.2 -> damage the heart, the brain, et cetera.

4636.44 -> I do want to give some voice to situations

4639.67 -> where too little salt can actually cause problems,

4642.91 -> and this has everything to do with the nervous system,

4645.55 -> so without getting into excessive amounts of detail,

4648.69 -> the kidneys, as we talked about before,

4652.1 -> are going to regulate salt and fluid balance.

4654.81 -> The adrenal glands, which ride atop the kidneys,

4658.4 -> are going to make glucocorticoids, like aldosterone,

4661.2 -> and those are going to directly impact

4663.36 -> things like fluid balance,

4665.89 -> and, in part, they do that

4667.41 -> by regulating how much craving for

4670.56 -> and tolerance of salty solutions we have,

4674.57 -> and there's some really nice studies

4676.62 -> that have looked at so-called adrenalectomies.

4679.52 -> Now, this is an extreme case,

4680.84 -> and it's typically done in animal models,

4682.86 -> but it illustrates the role of the adrenals

4685.88 -> in salt preference.

4688.08 -> Basically, when the glucocorticoid system,

4691.71 -> meaning the release of these particular hormones

4694.13 -> from the adrenal glands,

4695.62 -> is eliminated by adrenalectomy, -ectomy means removal,

4700.14 -> then, the threshold for what's considered too salty

4703.1 -> really shifts, okay?

4704.86 -> So typically, when the adrenals are intact,

4709.24 -> a animal or a human

4711.46 -> will prefer a mildly salty

4714.23 -> to moderately salty solution if given a choice,

4717.94 -> and at some point,

4718.88 -> it's so salty that it just feels aversive,

4721.03 -> just like taking a gulp of seawater

4722.79 -> is almost always aversive.

4724.19 -> I can't think of an instance where it's not aversive,

4726.3 -> and actually drinking seawater can kill you

4727.95 -> because of the high osmolarity of seawater.

4731.14 -> You certainly don't want to drink seawater.

4733.75 -> Under conditions where the adrenals are missing,

4738.27 -> animals and humans will tend to prefer

4740.86 -> a higher sodium concentration fluid,

4744.1 -> and they will be willing to tolerate

4746.13 -> ingesting very high concentrations of sodium.

4748.93 -> Now, that's a very crude experiment,

4750.67 -> and not one that you want to do, I promise you,

4753.94 -> but I mention it

4755.7 -> because it illustrates the very direct relationship

4759.21 -> between the stress system,

4760.79 -> which is the glucocorticoid system,

4762.79 -> and the salt craving system,

4765.04 -> and this actually makes sense.

4766.91 -> Earlier, as we were talking about hypovolemic thirst,

4769.04 -> when there's a loss of blood pressure from,

4772.12 -> usually due to a loss of blood from the body,

4774.45 -> there's a salt craving

4775.6 -> in order to bring that blood volume back up

4777.47 -> because by ingesting salt,

4778.93 -> you bring fluid into the bloodstream.

4781.05 -> You're increasing that blood pressure,

4782.51 -> and you can restore the blood that's lost.

4784.84 -> Now, there are many examples where,

4786.94 -> if sodium levels get too low in the bloodstream,

4790.69 -> either because people are ingesting too little salt,

4794.08 -> or they're ingesting too much water

4796.39 -> and therefore excreting too much salt,

4799.06 -> that it can cause stress and anxiety.

4802.54 -> There's some really nice data

4803.67 -> that point to the fact that low dietary sodium

4806.47 -> can actually exacerbate anxiety in animal models,

4810.79 -> and to some extent,

4812.19 -> there's evidence for this in humans as well,

4814.73 -> and that should not come as a surprise.

4817.77 -> The whole basis for a relationship

4820.25 -> between the adrenal system,

4821.64 -> these glucocorticoids, things like aldosterone,

4824.05 -> and the craving for sodium

4825.83 -> is that the stress system is a generic system

4829.96 -> designed to deal with various challenges to the organism,

4833.9 -> to you or to me or to an animal,

4836.36 -> and those challenges can arrive in many different forms.

4841.1 -> It can be an infection. It can be famine.

4843.31 -> It can be lack of water and so on,

4846.53 -> but in general,

4847.53 -> the stress response is one of elevated heart rate,

4850.58 -> elevated blood pressure,

4852.03 -> and an ability to maintain movement

4854.29 -> and resistance to that challenge, 'kay?

4857.1 -> I've said this before, but I'll emphasize it again,

4860.16 -> there's this common misperception that stress makes us sick,

4863.18 -> and indeed, if stress lasts too long,

4865.28 -> it has a number of negative effects on our health,

4868.15 -> but more often than not, if we're pushing, pushing, pushing,

4872.38 -> we're studying or taking care of somebody

4874.12 -> or traveling like crazy,

4876.13 -> we don't tend to get sick under those conditions,

4878.66 -> but as soon as we stop,

4880.86 -> as soon as we reduce our adrenaline output,

4883 -> as soon as we reduce our glucocorticoid output

4885.75 -> from our adrenals,

4886.8 -> then we will get sick.

4888.11 -> That's a very common occurrence,

4889.66 -> and it's because stress actually activates our immune system

4893.33 -> in the short term,

4894.51 -> so I'd like to try and dispel this myth

4896.97 -> that stress actually suppresses the immune system,

4899.45 -> at least not in the short term.

4900.93 -> For long-term stress, it's a different issue.

4903.15 -> You don't want long-term ongoing stress,

4905.34 -> especially of several weeks or more.

4908.95 -> Nonetheless, it makes sense

4910.84 -> that bringing sodium into the body

4913.48 -> would be at least one way that we would be wired

4916.91 -> to counteract or to resist stressors, right?

4921.09 -> Stressors being the things on the outside coming at us,

4924.29 -> so it could be stressful relationships,

4925.87 -> stressful job situation, again, infection, and so on.

4931.45 -> It's clear from a number of studies

4932.9 -> that if sodium levels are too low,

4935.83 -> that our ability to meet stress challenges is impaired.

4939.6 -> Now, that doesn't mean

4940.433 -> to place your sodium intake cosmically high,

4943.92 -> but it does point to the fact that

4945.69 -> if you're feeling anxious,

4947.63 -> perhaps from low blood pressure,

4949.31 -> which can also give symptoms of anxiety,

4951.06 -> as we talked about before,

4952.33 -> but even if it's independent of low blood pressure,

4955.6 -> that slightly increasing sodium intake,

4958.56 -> again, I would encourage people to do this

4960.61 -> not in the context of processed foods and drinks,

4962.83 -> but ideally, in the form

4964.13 -> of maybe a little bit of sea salt and water

4966.29 -> or salting one's food a little bit more,

4968.56 -> that that can stabilize blood pressure

4972.03 -> and one's ability to lean into stressors and challenges,

4975.48 -> and I say this because I think that most people assume

4978.41 -> that adding salt is always bad,

4981.02 -> when, in fact, that's simply not the case.

4983.59 -> There are conditions,

4984.67 -> such as when we are under stress challenge,

4986.9 -> when there is a natural craving for more sodium,

4990.09 -> and that natural craving for more sodium

4992.3 -> is hardwired into us as a way to meet that challenge,

4996.14 -> so it's hard for me to know whether or not people out there,

4999.31 -> especially the listeners of this podcast,

5000.78 -> are getting too much, just enough, or too little sodium,

5004.86 -> so I can't know that.

5005.97 -> I'm shouting into a tunnel here.

5007.29 -> You have to decide how much sodium you are ingesting,

5011.18 -> but I think that there's some, for most people,

5014.1 -> especially people who are not hypertensive, prehypertensive,

5016.78 -> there's some wiggle room

5017.613 -> to explore whether more intake of sodium

5021.65 -> could actually be beneficial

5022.88 -> for suppressing some of the anxiety responses

5025.29 -> that they might feel under conditions of stress.

5027.31 -> Again, more studies need to be done.

5029.11 -> Certainly, more studies in humans need to be done,

5031.92 -> but the relationship between stress and sodium intake

5034.437 -> and the fact that additional sodium intake may be beneficial

5039.53 -> and indeed, is naturally stimulated by stress

5043.2 -> shouldn't be necessarily looked at as a pathological event.

5046.76 -> I know when some people get stressed,

5048.08 -> they crave salty foods.

5049.33 -> That's actually a hardwired biological phenomenon

5052.19 -> that you see, not just in humans, but in animals,

5054.61 -> because this is a very primitive mechanism

5057.03 -> whereby your body is preparing

5058.95 -> to meet any additional challenges and stressors.

5061.87 -> Now, we can't have a discussion about sodium

5063.75 -> without having a discussion about the other electrolytes,

5066.58 -> magnesium and potassium.

5069.05 -> Magnesium is important enough and an extensive enough topic

5072.2 -> that we should probably do an entire episode

5073.67 -> just on magnesium.

5076 -> For purposes of today's discussion,

5077.96 -> I just will briefly touch on some of the forms of magnesium

5081.8 -> that we've discussed on the podcast before

5083.84 -> in different contexts.

5085.67 -> I want to emphasize that many people

5087.56 -> are probably getting enough magnesium in their diet

5090.67 -> that they don't need to supplement magnesium.

5093.6 -> Some people, however, opt to supplement magnesium

5096.8 -> in ways that can support them,

5098.55 -> and there are many different forms of magnesium,

5100.65 -> and just in very brief passing,

5103.56 -> I'll just say that there is some evidence

5107.24 -> that you can reduce muscle soreness from exercise

5111.37 -> by ingestion of magnesium malate, M-A-L-A-T-E.

5115.76 -> I've talked before about magnesium threonate,

5120.07 -> T-H-R-E-N-O-A-T-E, magnesium threonate,

5124.29 -> for sake of promoting the transition into sleep

5127.15 -> and for depth of sleep

5128.13 -> and perhaps, again, highlighted perhaps,

5130.66 -> 'cause right now it's mainly animal studies

5133.02 -> and ongoing human studies,

5134.43 -> but the data aren't all in.

5135.77 -> Perhaps magnesium threonate can be used

5138.76 -> as a way to support cognitive function and longevity.

5142.95 -> That was discussed in the episode

5144.16 -> with Dr. Jack Feldman from UCLA.

5148.11 -> Typically, magnesium threonate is taken

5149.75 -> 30 to 60 minutes before bedtime in order to encourage sleep.

5153.04 -> You can go to our neural network newsletter

5154.66 -> and look for the one on sleep,

5156.38 -> and you can see the recommendations,

5158.11 -> or I should say, the options for that

5160.96 -> because, again, you should always check with your physician.

5163.17 -> Those aren't strict across-the-board recommendations,

5165.42 -> and then, there are other forms of magnesium:

5167.61 -> magnesium bisglycinate,

5169.02 -> which is a somewhat of an alternative to threonate,

5172.68 -> not known to have cognitive enhancing effects,

5174.57 -> but seems, at least on par with magnesium threonate

5178.69 -> in terms of promoting transition into

5180.59 -> and depth of sleep and so on.

5182.81 -> There are other forms of magnesium, magnesium citrate,

5185.62 -> which has other functions.

5187.55 -> Actually, magnesium citrate

5190.28 -> is a fairly effective laxative,

5194.1 -> not known to promote sleep and things of that sort,

5196.16 -> so a lot of different forms of magnesium,

5197.615 -> and there's still other forms out there.

5199.83 -> Many people are not getting enough magnesium.

5201.75 -> Many people are.

5202.67 -> Okay, that's magnesium.

5205.33 -> Anytime we're talking about sodium balance,

5207.56 -> we have to take into consideration potassium

5209.92 -> because the way that the kidney works

5212.04 -> and the way that sodium balance is regulated,

5213.85 -> both in the body and the brain,

5215.29 -> is that sodium and potassium

5217.1 -> are working in close concert with one another.

5219.89 -> There are a lot of different recommendations

5221.41 -> about ratios out there,

5223.84 -> and they range widely

5225.27 -> from two-to-one ratio of potassium to sodium.

5229.78 -> I've heard it in the other direction too.

5231.89 -> I've heard a two-to-one sodium to potassium.

5235.22 -> The recommendations vary.

5236.54 -> One of the sponsors of this podcast, for instance,

5238.64 -> LMNT, which I've talked about in this episode and before,

5242 -> the ratio there is a gram of sodium

5243.87 -> to 200 milligrams of potassium, 60 milligrams of magnesium,

5247.53 -> so there, they've opted

5248.84 -> for a five-to-one ratio

5252.43 -> of sodium to potassium,

5254.193 -> and, of course, many people opt

5255.49 -> to make their own hydration electrolyte formulas.

5257.76 -> They'll put sea salt into some water,

5259.32 -> maybe even ingest a potassium tablet.

5261.43 -> It all depends on the context,

5263.02 -> and an important contextual element is your diet,

5266.21 -> so, for instance, carbohydrates hold water in the body,

5269.33 -> so regardless of how much salt

5270.64 -> and how much fluid you're ingesting,

5272.12 -> if you're ingesting carbohydrate

5273.45 -> and you drink fluids, water,

5276.78 -> some of that fluid is going to be retained in the body.

5279.1 -> Now, for people that are following low-carbohydrate diets,

5282.29 -> one of the most immediate effects of a low-carbohydrate diet

5285.56 -> is that you're going to excrete more water,

5287.43 -> and so, under those conditions,

5289.13 -> you're also going to lose not just water,

5291.29 -> but you'll probably also lose sodium and potassium,

5293.8 -> and so some people, many people, in fact,

5296.89 -> find that when they are on a lower or low-carbohydrate diet,

5300.32 -> then they need to make sure

5301.36 -> that they're getting enough sodium and enough potassium,

5304.34 -> and some people do that

5305.21 -> by taking 99-milligram potassium tablets

5307.45 -> every time they eat.

5308.45 -> Some people do that

5309.283 -> by ingesting more foods that contain potassium,

5313.82 -> and, of course,

5314.653 -> some people who are on low-carbohydrate diets

5316.63 -> do ingest vegetables

5318.88 -> or other forms of food that carry along with them potassium,

5322.93 -> so it's quite variable from person to person.

5327.26 -> I mean, you can imagine if carbohydrate holds water,

5330.3 -> water and salt balance and potassium

5332.69 -> go hand in hand, and hand,

5334.65 -> that if you're on a low-carbohydrate diet,

5336.53 -> that you might need to adjust

5337.46 -> your salt intake and potassium,

5339.03 -> and conversely, that if you're on a carbohydrate-rich diet

5342.14 -> or a moderate carbohydrate diet,

5343.42 -> then you may need to ingest less sodium and less potassium,

5346.38 -> and, in fact, a certain amount of water

5348.15 -> is probably coming in through the foods you eat as well,

5350.72 -> so I don't say all this to confuse you.

5352.69 -> Again, I say this because it all depends on the context.

5357.6 -> I'll give yet another context

5358.94 -> that I think is fairly common nowadays,

5361.45 -> which is many people are following a pattern of eating

5365.03 -> that more or less resembles intermittent fasting

5367.98 -> or at least time-restricted feeding,

5369.46 -> so they're eating between particular feeding windows,

5372.45 -> and then, in the certain parts of the 24-hour cycle,

5375.32 -> not just sleep,

5376.34 -> but during certain parts of their waking cycle,

5378.1 -> they're also actively avoiding food,

5380.49 -> banking on, I think, either the possible,

5384.09 -> I want to say possible, longevity-promoting effects

5387.28 -> of intermittent fasting,

5388.53 -> or, and/or, I should say,

5391 -> they are banking on the fact that for many people,

5393.66 -> not eating is easier than portion control

5396.14 -> for certain parts of the day,

5396.973 -> and so they find it beneficial to limit calories overall

5401.16 -> to a given amount, depending on what their goals are,

5403.92 -> by not consuming food for certain periods of the day,

5407.88 -> but usually, during those periods of the day,

5409.37 -> they're consuming fluids,

5410.64 -> and oftentimes, those fluids include not just water,

5412.78 -> but caffeine, and caffeine is a diuretic.

5415.4 -> It actually causes the excretion of fluids from the body

5418.63 -> in part, because it causes the excretion of sodium.

5423.4 -> All of that to say

5424.36 -> that if you're somebody who, for instance,

5426.43 -> eats your first meal around noon or 1:00 or 2:00 p.m.,

5429.06 -> and you're fasting for the early part of the day,

5431.01 -> and you're drinking coffee or tea

5432.63 -> or ingesting a lot of water,

5435.43 -> you are going to be excreting sodium along with that water,

5439.1 -> and so many people, including myself, find that it's useful,

5442.47 -> especially when I'm drinking caffeine

5445.14 -> during that so-called fasting

5446.94 -> or nonfood intake part of time-restricted feeding,

5451.29 -> that I'm making sure to get enough salt,

5453.46 -> either in the form of something like LMNT,

5456.24 -> an electrolyte drink,

5457.21 -> or putting some sea salt into some water,

5459.39 -> or certainly, anytime one is ingesting caffeine,

5463.71 -> replacing some of the lost water

5465.63 -> by increasing one's water intake.

5467.65 -> There are some simple rules of thumb around this

5470.56 -> that I think can get most people into a place

5473.34 -> where they're more comfortable and functioning better,

5475.95 -> which is for every ounce of coffee or tea that you drink,

5480.32 -> I should say caffeinated coffee or tea that you drink,

5482.76 -> that you consume 1 1/2 times as much water,

5486.3 -> so let's say you have an 8-ounce coffee,

5489.01 -> try and drink about, you don't have to be exact,

5490.82 -> but try and drink about a 12-ounce glass of water,

5493.61 -> and you might want to put a tiny bit of sodium into that.

5495.81 -> By tiny bit, I just mean a tiny pinch of sodium

5498 -> because remember, even if we're talking

5500.17 -> about increasing the amount of sodium intake overall,

5503.76 -> the total amount of sodium contained in salt

5507.03 -> is sufficiently high that even just 1/4 teaspoon

5510.25 -> is going to really start to move that number

5511.77 -> up towards that range that's still within the safe range,

5514.67 -> but you're going to, if you keep doing that all day long,

5517.14 -> you're very quickly

5517.973 -> going to get into that excessive salt intake range

5519.87 -> that is deleterious for health,

5521.91 -> so again, if you're consuming more caffeine,

5523.55 -> you're going to be excreting water and salt and potassium,

5526.31 -> and so you're going to have to find ways

5527.62 -> to bring water, salt, and potassium back in.

5529.64 -> Again, this has to be evaluated

5531.55 -> for each of your own individual situations.

5534.14 -> If you're exercising fasted,

5537.11 -> and you're doing that after drinking caffeine,

5539.74 -> then before, during, and certainly after exercise,

5543.52 -> you're going to want to replenish

5544.81 -> the fluids and electrolytes that you lost, including sodium,

5548.35 -> so you can imagine

5549.73 -> how this all starts to become pretty dizzying,

5551.92 -> and yet it doesn't have to be dizzying.

5553.47 -> We can provide some useful ranges

5555.12 -> that, for most people, will work,

5557.29 -> and so let's talk about what those ranges are,

5559.05 -> and I'm going to point you to a resource

5560.7 -> that explores what those ranges are

5562.45 -> in these various contexts of nutrition, exercise, and so on.

5565.85 -> The resource is a book

5567.61 -> that was authored by Dr. James DiNicolantonio.

5571.67 -> He's not a medical doctor.

5573.11 -> He's a scientist,

5574.91 -> so he's cardiovascular physiology

5578.39 -> as well, I believe, as a doctor of pharmacy,

5580.72 -> and the title of the book is "The Salt Fix."

5582.677 -> "The Salt Fix" is an interesting read

5584.26 -> because it points to, first of all,

5586.39 -> the history of salt in society

5589.35 -> and as it relates to health.

5591.78 -> It actually emphasizes some of the major missteps,

5594.79 -> maybe even pretty drastic errors,

5596.99 -> that have been made in terms of trying to interpret the role

5600.37 -> that salt has in various diseases

5604.3 -> and emphasizes some of the ways in which, perhaps,

5608.47 -> increasing salt can actually improve health outcomes,

5611.73 -> and I think it strikes a pretty nice balance

5613.87 -> between what's commonly known about salt

5616.88 -> and what I believe ought to be known about salt,

5620.37 -> or at least taken into consideration.

5623.36 -> The book does provide certain recommendations,

5626.57 -> and I actually reached out to the author.

5628.42 -> I've never met him in person or talked to him directly,

5631.35 -> and I asked him outright.

5634.05 -> I said, "How much salt

5636.207 -> "do you recommend people take on average?"

5639.29 -> And he gave, of course, the appropriate caveats

5643.03 -> about prehypertension, hypertension, et cetera,

5645.48 -> but made a recommendation which I'll just share with you,

5649.99 -> and if you want to learn more

5651.35 -> about the support for this recommendation,

5653.61 -> you can check out his book.

5655.55 -> The recommendation he made was

5656.79 -> anywhere from 8 to 12 grams of salt a day,

5659.56 -> which corresponds to

5661.37 -> 3.2 to 4.8 grams of sodium,

5664.95 -> so going back to the current recommendations

5668.99 -> that we talked about before, 2.3 grams of sodium per day,

5672.27 -> this is about 1 1/2 times

5674.11 -> to double the amount of sodium

5677.96 -> that's currently recommended in most circles,

5680.94 -> and then, what this corresponds to

5682.33 -> is about 1 1/2 to 2 teaspoons of salt per day

5686.3 -> to arrive at that 3.2 to 4.8 grams of sodium.

5689.12 -> Again, this is the recommendation

5691.27 -> that was passed along for most people, most conditions,

5694.99 -> barring specific health issues.

5698.8 -> Now, what was also interesting is

5699.93 -> he pointed to a sodium-to-potassium ratio,

5703.35 -> which is 4 grams of potassium,

5706.41 -> and he also mentioned 400 milligrams of magnesium,

5708.94 -> and pointed out, and I generally agree here,

5711.17 -> that many people are deficient in magnesium,

5714.09 -> so again, that was a 3.2 to 4.8 grams of sodium,

5718.92 -> 4 grams of potassium.

5721.06 -> You might think, "Well, gosh,

5721.927 -> "that's 1 1/2 to 2 times the current recommendation,"

5724.88 -> but we can go back to that study

5727.67 -> that was mentioned earlier in the episode,

5729.43 -> that 2011 study,

5730.74 -> where I describe this sort of J-shaped curve

5734.93 -> in which, when you look at the occurrence

5737.72 -> of these negative health events,

5739.37 -> they were fairly low at low sodium intake,

5742.49 -> lower still at slightly higher sodium intake,

5745.54 -> much in line with the recommendations that are made

5748.55 -> or that Dr. DiNicolantonio passed along to me,

5753.05 -> and then, they increased quite,

5754.7 -> those health risks increased quite substantially

5757.52 -> as one moves out past 6 grams of sodium,

5760.91 -> 7 grams of sodium per day.

5762.13 -> That's when things really do seem to get hazardous,

5765.92 -> and really, it makes sense, I think,

5768.62 -> given the consensus around this,

5770.24 -> to really avoid very high salt intake,

5773.24 -> so "The Salt Fix" describes the rationale

5777.22 -> behind those recommendations.

5779.117 -> "The Salt Fix" also describes, in quite beautiful detail,

5783.43 -> the relationship between salt intake, potassium intake,

5787.47 -> and the relationship to the sugar consumption system.

5791.09 -> I'd like to pick up on this idea

5792.5 -> of the relationship between salt and sugar

5795.98 -> because I think that one key aspect

5798.65 -> of the way that salt can work

5800.51 -> and can benefit us or can harm us has to do with the way

5803.81 -> that sodium and sugar are regulated

5807.24 -> and actually perceived by the brain

5809.15 -> and how,

5809.983 -> under conditions of certain levels of sodium intake,

5812.63 -> we might be inspired to seek more sugar

5814.57 -> or to crave sweets more or less,

5816.86 -> so up until now,

5817.693 -> we've been talking about salt as a substance

5819.78 -> and a way to regulate fluid balance

5821.94 -> and blood volume and so on.

5824.24 -> We haven't talked a lot about salt as a taste

5826.35 -> or the taste of things that are salty,

5828.96 -> and yet we know that we have salt receptors,

5832.32 -> meaning neurons,

5833.99 -> that fire action potentials

5836.35 -> when salty substances are detected,

5838.82 -> much in the same way that we have sweet detectors

5840.95 -> and bitter detectors,

5842.41 -> and we have detectors of umami, the savory flavor,

5846.11 -> on our tongue,

5847.16 -> and earlier, at the beginning of the episode,

5849.18 -> I talked about the fact that we have sweet receptors,

5853.07 -> neurons that respond to the presence of sugar

5855.49 -> or even noncaloric sweet things in the gut,

5858.85 -> and that signals up to the brain through the vagus nerve,

5862.15 -> and those signals converge on pathways

5864.06 -> that relate to dopamine and so on.

5865.96 -> Well, we also have salt sensors

5867.92 -> at various locations throughout our digestive tract,

5871.06 -> although the sensation and the taste of salt

5873.63 -> actually exerts a very robust effect

5876.69 -> on certain areas of the brain

5879.04 -> that can either make us crave more

5881.72 -> or sate, meaning fulfill, our desire for salt,

5886.05 -> and you can imagine why this would be important.

5887.94 -> Your brain actually has to register

5889.27 -> whether or not you're bringing in salt

5891.72 -> in order to know whether or not

5893.41 -> you are going to crave salt more or not,

5896.56 -> and beautiful work that's been done by the Zuker Lab,

5899.6 -> Z-U-K-E-R, Zuker Lab at Columbia University,

5902.44 -> as well as many other labs

5903.92 -> have used imaging techniques

5905.44 -> and other techniques such as molecular biology

5907.44 -> to define these so-called parallel pathways,

5909.43 -> parallel meaning pathways that represent sweet

5912.97 -> or the presence of sweet taste in the mouth and gut,

5916 -> parallel pathways, meaning neural circuits

5917.83 -> that represent the presence of salty tastes

5920.03 -> in the mouth and gut and so on,

5921.91 -> and that those go into the brain,

5924.47 -> move up through brain stem centers

5926.71 -> and up to the neocortex

5928.23 -> indeed where our seed of our conscious perception is

5930.64 -> to give us a sense and a perception

5933.44 -> of the components of the foods

5936.303 -> that we happen to be ingesting

5937.96 -> and a sense and a perception of the fluids

5940.77 -> and the components of those fluids

5942.1 -> that we happen to be ingesting.

5944.07 -> Now, parallel pathways, as I'm describing them,

5946.95 -> are a fundamental feature of every sensory system,

5950.73 -> not just the taste system, but also the visual system.

5953.4 -> We have parallel pathways

5954.42 -> for perceiving dark objects versus light objects,

5956.81 -> for perceiving red versus green, et cetera.

5959.86 -> This is a fundamental feature of how we are built

5962.62 -> and how our nervous system works,

5964.3 -> and in the taste system, much like in these other systems,

5968.72 -> these pathways are indeed parallel,

5971.35 -> but they converge, and they can influence one another,

5974.53 -> and I think the simplest way to put this

5976.57 -> is in the context, first, of the visual system,

5978.56 -> whereby your ability to detect the color red

5982.34 -> has everything to do with the fact

5983.88 -> that you have neurons in your eye

5985.81 -> that absorb long wavelengths of light that we call reds,

5989.4 -> red wavelengths of light,

5990.59 -> which are longer wavelengths than, say, blue light,

5993.93 -> which are shorter wavelength,

5995.24 -> but it is really the comparison of the electrical activity

5998.21 -> of the neurons that absorb red light

6000.36 -> with the activity of the neurons that absorb green light

6003.52 -> which actually gives you the perception of red,

6005.75 -> so that might seem a little counterintuitive,

6007.98 -> but indeed, it's not.

6009.3 -> It's actually because something is red

6012.74 -> and has less greenness

6014.89 -> that we perceive it as more red than the green,

6018.37 -> and this is actually the way

6019.63 -> that your entire nervous system works

6021.67 -> is that we aren't really good

6023.3 -> at evaluating absolute levels of anything

6025.86 -> in the context or perception.

6027.08 -> It's only by comparison,

6029.47 -> and actually, there's a fun experiment that you can do,

6031.53 -> I think you could probably find it easily online,

6033.387 -> but you could also do this experiment at home.

6035.12 -> You can stare at something that's red,

6038.06 -> or green, for that matter, for a while,

6040.17 -> so you make an active decision to not blink

6044.27 -> and to stare at something that's red,

6046.02 -> and then you look away from that thing,

6047.93 -> and you'll actually see a green afterimage

6050.45 -> of that red object.

6051.84 -> Conversely, if you look at something

6053 -> that's green for a while,

6054.27 -> and you stare at it, and you look away,

6055.71 -> you will see the red afterimage of that thing.

6058.74 -> Now, the taste system doesn't have

6060.16 -> quite the same aftertaste type effect,

6064.42 -> but nonetheless, the pathways,

6067.16 -> the parallel pathways for salty

6068.76 -> and the parallel pathways for sweet and bitter and so on

6072.28 -> can actually interact,

6073.377 -> and this has important relevance

6074.89 -> in the context of food choices and sugar craving.

6078.55 -> One of the things that's commonplace nowadays is

6081.73 -> in many processed foods there is a business, literally,

6085.41 -> a business of putting so-called hidden sugars,

6088.29 -> and these hidden sugars

6089.16 -> are not always in the form of caloric sugars.

6091.15 -> They're sometimes in the form of artificial sweeteners

6093.71 -> into various foods,

6095.27 -> and you might say, "Well,

6096.727 -> "why would they put more sugar into a food

6098.937 -> "and then disguise the sugary taste

6101.117 -> "given that sweet tastes often compel people

6103.387 -> "to eat more of these things?"

6104.98 -> Well, it's a way, actually,

6106.73 -> of bypassing some of the homeostatic mechanisms for sweet,

6111.01 -> even though we might think that the more sweet stuff we eat,

6113.37 -> the more sweet stuff we crave,

6115.16 -> in general, people have a threshold

6116.74 -> whereby they say, "Okay, I've had enough sugary stuff."

6119.97 -> You can actually experience this.

6121.65 -> If you ever feel like something is really, really sweet,

6124.37 -> take a little sip of water

6126.45 -> with a little bit of lemon juice in it or vinegar,

6128.21 -> and it will quickly quench

6129.84 -> that overly sweet sensation or perception.

6132.82 -> It will disappear almost immediately.

6134.76 -> There's actually a practice in fancy meals

6137.27 -> of cleansing the palate

6139.2 -> through the ingestion of different foods,

6141 -> and that's the same idea that you're cleansing the palate.

6142.68 -> You're actually neutralizing the previous taste

6145 -> so then they can bring yet another dish

6146.98 -> to overindulge you in decadence and so forth,

6150.19 -> so these sensory systems interact in this way.

6154.32 -> By putting sugars into foods

6156.99 -> and hiding the sugary taste of those foods,

6160.15 -> those foods, even if they contain artificial sweeteners,

6163.66 -> can activate the sorts of neurons

6165.55 -> that we talked about at the beginning of the episode,

6167.18 -> like the neuropod cells

6168.8 -> that will then signal to the brain to release more dopamine

6171.4 -> and make you crave more of that food,

6172.99 -> whereas had you been able

6174.36 -> to perceive the true sweetness of that food,

6177.77 -> you might have consumed less,

6178.907 -> and indeed, that's what happens,

6180.44 -> so these hidden sugars are kind of diabolical.

6183.34 -> Why am I talking about all of this

6185.08 -> in the context of an episode on salt?

6187.85 -> Well, as many of you have probably noticed,

6190.54 -> a lot of foods out there

6192.31 -> contain a salty-sweet combination,

6195.44 -> and it's that combination of salty and sweet

6198.33 -> which can actually lead you to consume

6199.87 -> more of the salty-sweet food than you would have

6204.81 -> if it had just been sweet or it had just been salty,

6208.3 -> and that's because both sweet taste and salty taste

6212.59 -> have a homeostatic balance,

6214.44 -> so if you ingest something that's very, very salty,

6216.55 -> pretty soon your appetite for salty foods will be reduced,

6219.4 -> but if you mask some of that with sweet,

6221.83 -> well, because of the interactions

6224.52 -> of these parallel pathways,

6225.96 -> you somewhat shut down your perception

6228.29 -> of how much salt you're ingesting,

6230.68 -> or conversely, by ingesting some salt with sweet foods,

6233.93 -> you mask some of the sweetness

6235.79 -> of the sweet foods that you're tasting,

6237.11 -> and you will continue to indulge in those foods,

6238.99 -> so salty-sweet interactions can be very diabolical.

6243.13 -> They can also be very tasty,

6244.47 -> but they can be very diabolical

6245.84 -> in terms of inspiring you to eat more of a particular food

6248.91 -> than you would otherwise

6250.23 -> if you were just following your homeostatic salt

6253.25 -> or your homeostatic sugar balance systems,

6256.7 -> and the beautiful imaging work that's been done

6258.83 -> by the Zuker Lab and other labs

6260.48 -> has actually been able to reveal how some of this might work

6263.53 -> by showing, for instance, that a certain ensemble,

6266.76 -> meaning a certain group of neurons,

6268.34 -> is activated by a sweet taste

6270.65 -> and a nonoverlapping distinct set of neurons just nearby

6274.28 -> sitting cheek-to-jowl with those other neurons

6277.13 -> would be activated by salty tastes

6279.33 -> and yet others by bitter taste et cetera,

6281.22 -> so there's a separate map

6282.87 -> of these different parallel pathways,

6284.59 -> but that when foods or fluids are ingested

6287.81 -> that are both salty and sweet,

6290.05 -> you get a yet entirely different ensemble

6293.35 -> of neurons activated,

6294.78 -> so your brain, whether or not it's for your visual system

6298.59 -> or your auditory system or your taste system,

6300.61 -> has a way of representing the pure form of taste,

6303.46 -> salty, sweet, bitter, et cetera,

6305.08 -> and has a way of representing their combinations,

6307.82 -> and food manufacturers have exploited this to large degree.

6312.1 -> I mention all of this

6313.19 -> because if you're somebody who's looking to explore

6316.74 -> either increasing or decreasing your sodium intake

6319.86 -> for health benefits, for performance benefits,

6322.97 -> in many ways, it is useful to do that

6325.67 -> in the context of a fairly pure,

6328.2 -> meaning unprocessed food intake background,

6331 -> whether or not that's key to a carnivore, omnivore,

6334.93 -> intermittent fasting, or what have you.

6336.45 -> It doesn't really matter,

6337.57 -> but the closer that foods are to their basic form and taste,

6342.06 -> meaning not large combinations

6344.5 -> of large amounts of ingredients

6346.33 -> and certainly avoiding highly processed foods,

6349.14 -> the more quickly you're going to be able to hone in

6351.75 -> on your specific salt appetite and salt needs,

6354.91 -> which, as I've pointed out numerous times

6356.96 -> throughout this episode,

6357.793 -> are going to vary from person to person

6359.4 -> depending on nutrition, depending on activity,

6361.32 -> depending on hormone status,

6362.95 -> or even portion of your menstrual cycle, for that matter,

6366.06 -> so if you want to home in

6367.94 -> on the appropriate amount of sodium for you,

6369.84 -> yes, blood pressure is going to be an important metric

6372.78 -> to pay attention to as you go along,

6374.36 -> and the parameters for healthy blood pressure ranges

6376.77 -> are readily available online,

6378.24 -> so I'll let you refer to those

6379.99 -> in order to determine those for yourself,

6381.9 -> but in determining whether or not

6384.56 -> increasing your salt intake might be beneficial,

6387.68 -> for instance, for reducing anxiety a bit

6389.53 -> or for increasing blood pressure

6391.21 -> to offset some of these postural syndromes

6393.61 -> where you get dizzy, et cetera,

6394.93 -> for improving sports performance or cognitive performance,

6399.15 -> I can only recommend that you do this

6401.84 -> in a fairly clean context

6403.62 -> where you're not trying to do this

6404.73 -> by ingesting a bunch of salty foods

6406.48 -> or salty-sweet foods, et cetera,

6408.6 -> and indeed, many people find,

6410.09 -> and it's reviewed a bit,

6411.44 -> and some of the data are reviewed

6413.04 -> in the book "The Salt Fix,"

6414.89 -> that when people increase their salt intake

6417.86 -> in a backdrop of relatively unprocessed foods,

6421.62 -> that sugar cravings can indeed be vastly reduced,

6424.47 -> and that makes sense

6425.56 -> given the way that these neural pathways

6427.32 -> for salty and sweet interact.

6429.04 -> Now, thus far, I've already covered quite a lot of material,

6432.93 -> but I would be completely remiss

6435.44 -> if I didn't emphasize the crucial role that sodium plays

6439.82 -> in the way that neurons function.

6441.7 -> In fact, sodium is one of the key elements

6444.61 -> that allows neurons to function at all,

6447.32 -> and that's by way of engaging

6448.67 -> what we call the action potential.

6450.65 -> The action potential

6452.24 -> is the firing of electrical activity by neurons.

6457.09 -> Now, neurons can engage electrical activity

6459.81 -> in a number of different ways.

6460.92 -> They have graded potentials. They have gap junctions.

6464.22 -> There's a whole landscape

6465.75 -> of different electrophysiologies of neurons

6469.02 -> that I don't want to go into just yet,

6471.63 -> at least not in this episode,

6473.33 -> but the action potential is the fundamental way

6475.98 -> in which neurons communicate with one another.

6478.66 -> They're sometimes called spikes.

6480.77 -> It's just kind of nomenclature that neuroscientists use.

6484.29 -> I'm just going to briefly describe the action potential

6486.46 -> and the role that sodium plays,

6488.4 -> and this will involve a little bit of chemistry,

6490.83 -> but I promise it will be accessible to anyone,

6493.16 -> even if you don't have a chemistry or a physics background

6495.41 -> or electrophysiology background.

6498.14 -> Neurons have an inside and an outside,

6500.85 -> and inside are things like your genetic material.

6505.68 -> They have a bunch of things floating around in there

6507.84 -> that allow those cells to function,

6509.77 -> and they tend to have this wire extending out of them,

6512.81 -> sometimes a very long wire, sometimes a short one,

6514.74 -> that we call the axon,

6516.14 -> and at the end of that wire, that axon,

6519.24 -> they release little packets of chemicals

6522.51 -> that either cause the next neuron to fire action potentials

6527.16 -> or prevent the next neuron from firing action potentials,

6529.97 -> so they kind of vomit out these little packets of chemicals

6533.9 -> that either inspire or suppress action potentials

6537.8 -> in other neurons.

6540.24 -> The way that that whole process occurs

6543.83 -> is that a given neuron

6545.5 -> needs to change its electrical activity,

6548.58 -> so normally, neurons are hanging out,

6552.02 -> and they have what we call a negative charge,

6553.87 -> and the reason they have a negative charge

6556.36 -> is that the inside of the cell

6558.26 -> has things floating around in it

6559.67 -> like potassium, a little bit of sodium,

6562.46 -> and some stuff like chloride.

6563.94 -> These are literally just,

6565.12 -> just imagine these as little balls of stuff,

6568.5 -> and if they have a negative charge on them,

6571.283 -> then the inside of the cell

6572.65 -> is going to tend to be more negative,

6574.08 -> and outside of the cell, it turns out,

6576.16 -> you're going to have a bunch of stuff

6578.65 -> that's positively charged,

6580.71 -> and one of the main factors

6582.73 -> in creating that positive charge is sodium.

6584.97 -> Sodium carries a positive charge,

6587.1 -> so you have neurons that you can just imagine a,

6590.42 -> for sake of this discussion,

6592.22 -> you can just imagine as a sphere

6593.67 -> with a little wire sticking out of it.

6596.7 -> You can put a little minus on the inside for negative.

6598.81 -> You can put a little plus on the outside for positive,

6601.3 -> and when that neuron is stimulated by another neuron,

6606.02 -> if the stimulation,

6607.14 -> the electrical stimulation is sufficiently high,

6611.24 -> meaning enough little packets of neurotransmitter

6614.67 -> have been vomited onto its surface

6617.25 -> at sufficient concentration,

6619.27 -> what happens is little pores, little spaces,

6624.04 -> little gaps open up in the membrane of that cell

6628.75 -> that separates the inside from the outside,

6631.84 -> and because it's positive,

6634.15 -> there's a lot of positive charge outside,

6635.95 -> and there's a lot of negative inside,

6638.35 -> it's like a boulder running downhill.

6640.5 -> All the stuff tends to rush downhill.

6642.63 -> It tries to create even amounts of charge,

6644.73 -> so it's negative on the inside, positive on the outside,

6647.23 -> and what happens is sodium rushes into the cell

6651.45 -> carrying a lot of charge into the cell,

6653.58 -> and as a consequence,

6655.08 -> the charge of that cell goes from negative,

6657.61 -> actually, very negative, to quite positive,

6660.33 -> and if it hits a certain threshold of positive charge

6663.86 -> because of all the sodium ions going into the cell,

6667.43 -> then it fires what's called an action potential,

6670.35 -> and it vomits out its own set of chemicals

6673.58 -> onto the next neuron,

6674.47 -> and so it sets off a chain

6675.77 -> of one neuron goes from negative to positive,

6678.34 -> blech, vomits out chemicals onto the next one.

6680.63 -> The next one, the next neuron,

6683.27 -> that binds to receptors or enters the cell,

6686.23 -> and that cell goes from negative to positive charge,

6689.631 -> [imitates vomiting] vomits its contents onto the next cell,

6692.18 -> and so on and so forth.

6695.51 -> Sodium rushing into the cell, therefore,

6697.89 -> is the way that the action potential is stimulated.

6701.27 -> In other words, sodium is the way

6704.33 -> that neurons communicate with one another.

6706.77 -> Now, the neurons don't stay in a positive charge.

6710.08 -> Otherwise, they would just keep vomiting out their contents,

6712.413 -> [imitates vomiting], but they need to maintain some of that,

6714.867 -> and they need to go back

6715.81 -> to preparing to do it the next time and the next time

6718.04 -> by resting a bit,

6719.37 -> and turns out that the way they restore their charge

6722.06 -> is by pushing that sodium back out of the cell.

6726.23 -> There are mechanisms in place to do that,

6728.32 -> things like the so-called sodium-potassium pump.

6731.26 -> There's a change in the levels of the potassium

6734.55 -> across the cell membrane and so on and so forth.

6736.64 -> If you want to look at a demonstration of this,

6738.051 -> you can just,

6738.884 -> you can put into a web browser the action potential.

6742.89 -> You'll find some beautiful descriptions there

6744.65 -> on YouTube and elsewhere.

6746.6 -> Maybe some time on Instagram,

6748.37 -> I'll do a description with a diagram

6750.31 -> 'cause I realize

6751.24 -> number of people are just listening to this.

6753.04 -> I can't do that here.

6754.13 -> I won't do that here

6755.52 -> 'cause I want everyone

6756.353 -> to be able to get the same amount of material

6757.88 -> regardless of whether or not they're watching

6759.22 -> and/or listening to this,

6760.9 -> but the point I'd like to make,

6763.73 -> at least as it relates to this episode on salt,

6765.8 -> is that having sufficient levels of salt in your system

6769.89 -> allows your brain to function,

6771.31 -> allows your nervous system to function at all.

6773.39 -> Again, this is the most basic aspect

6775.43 -> of nervous system function,

6777.1 -> and there are cases

6778.55 -> where this whole system gets disrupted,

6782.29 -> and that brings us to the topic of sodium and water balance.

6787.21 -> As many of you have probably heard,

6788.48 -> but hopefully, if you haven't,

6790.76 -> you'll take this message seriously,

6793.1 -> if you drink too much water,

6795.82 -> especially in a short amount of time,

6797.78 -> you can actually kill yourself, right?

6800.4 -> And we certainly don't want that to happen.

6802.73 -> If you ingest a lot of water in a very short period of time,

6807.37 -> something called hypernatremia,

6810.07 -> you will excrete a lot of sodium very quickly,

6812.78 -> and your ability to regulate kidney function

6815.08 -> will be disrupted,

6816.17 -> but in addition to that,

6817.66 -> your brain can actually stop functioning,

6819.64 -> so people have actually consumed water to excess,

6823.57 -> especially after sports events and so forth,

6825.85 -> and if that water doesn't contain sufficient electrolytes,

6829.25 -> you can actually shut down neurons' ability

6831.42 -> to function at all

6832.45 -> by disrupting this balance of sodium and potassium

6836.51 -> and the amount of extracellular sodium

6838.43 -> and neurons' ability to signal to one another

6841.85 -> through action potentials,

6843.33 -> and I can't emphasize the importance

6844.83 -> of action potentials enough.

6846.11 -> They are the way that I can lift my pen right now.

6848.23 -> They're the way that I can speak.

6849.22 -> They're the way that you breathe.

6850.78 -> They literally control all aspects

6852.66 -> of your nervous system function.

6854.42 -> Now, it takes quite a lot of water intake

6856.14 -> before you excrete enough sodium

6858.07 -> that your nervous system is going to shut down,

6860.12 -> and I certainly don't want to give the impression

6861.69 -> that simply by ingesting more sodium,

6863.31 -> your neurons will work better,

6864.94 -> but it absolutely is the case

6866.35 -> that if you don't ingest enough sodium,

6868.81 -> that your neurons won't function as well as they could,

6871.53 -> and that if your sodium levels are made too low

6875.63 -> by hemorrhage

6876.97 -> or by ingesting so much water, fluid,

6881.46 -> that you excrete excess amounts of sodium

6884.34 -> or through any other mechanism, that is,

6886.91 -> then indeed your neurons

6888.36 -> won't be able to fire action potentials

6889.727 -> and your brain and nervous system simply won't work,

6892.31 -> and that's one of the primary reasons why dehydration

6894.88 -> leads to confusion and dizziness and lack of coordination,

6898.85 -> and I've talked about this a bit

6900.39 -> in the episode on endurance,

6901.96 -> but there are instances

6903.69 -> in which competitive athletes have come into the stadium

6906.9 -> to finish a final lap of a long endurance race

6909.34 -> and are completely disoriented

6910.89 -> and actually can't find their way to the finish line.

6912.91 -> It might sound like kind of a silly, crazy example,

6915.5 -> but there are examples

6917.06 -> of people having severe mental issues

6920.47 -> and physical issues post-exercise

6922.97 -> when that exercise involved a ton of sweating

6925.23 -> or hot environments

6926.1 -> or insufficient ingestion of fluids and electrolytes

6929.41 -> because included in the electrolyte formula,

6931.42 -> of course, is sodium,

6932.81 -> and as you just learned,

6933.75 -> sodium is absolutely crucial for neurons to function,

6936.98 -> so to briefly recap some of what I've talked about today,

6940.77 -> we talked about how the brain monitors the amount of salt

6943.83 -> in your brain and body

6945.2 -> and how that relates to thirst

6947.22 -> and the drive to consume more fluid and/or salty fluids.

6951.78 -> We also talked a little bit about the hormones

6953.92 -> that come from the brain

6954.753 -> and operate at the level of the kidney

6957.18 -> in order to either retain

6958.98 -> or allow water to leave your system.

6962.75 -> Talked a little bit about the function of the kidney itself,

6965.46 -> a beautiful organ.

6966.91 -> We talked about the relationship

6969.41 -> between salt intake and various health parameters

6972.93 -> and how a particular range of salt intake

6976.42 -> might be optimal,

6978.7 -> depending on the context

6980.85 -> in which that range is being consumed,

6982.42 -> meaning depending on whether or not

6984.82 -> you're hypertensive, prehypertensive, or normal tension.

6987.92 -> We talked about fluid intake and electrolyte intake,

6990.35 -> so sodium, potassium, and magnesium

6992.04 -> in the context of athletic or sports performance,

6995.32 -> but also, in terms of maintaining cognitive function.

6997.62 -> Talked about the Galpin equation,

6999.18 -> which you could easily adapt to your body weight

7001.747 -> and to your circumstances.

7003.94 -> Of course, adjusting the amount of fluid

7006.87 -> and electrolyte intake upwards

7009.29 -> if you're exercising or working in very hot environments,

7013.06 -> downwards, maybe, if you're in less hot environments

7016.14 -> where you're sweating less and so on.

7017.88 -> We also talked about the relationship

7019.29 -> between the stress system and the salt craving system

7022.91 -> and why those two systems interact

7025.4 -> and why, for some people who may suffer a bit

7029.06 -> from anxiety or under conditions of stress,

7032.28 -> increasing salt intake,

7033.6 -> provided it's done through healthy means,

7035.73 -> might actually be beneficial.

7038.07 -> We also talked about conditions

7039.3 -> in which increasing salt intake might be beneficial

7042.41 -> for offsetting low blood pressure,

7044.98 -> and some of these postural syndromes

7046.65 -> that can lead people to dizziness and so forth.

7049.14 -> These are things that have to be explored

7050.62 -> on an individual basis,

7051.79 -> and, of course, have to be explored

7054.04 -> with the support of your doctor.

7055.94 -> I mentioned "The Salt Fix,"

7057.47 -> which I think is an interesting read,

7059.32 -> keeping in mind that a lot of the information in there

7061.46 -> runs counter to the typical narrative

7063.64 -> that you hear around salt,

7065.07 -> but nonetheless, has some very interesting points

7067.3 -> that you might want to consider

7068.92 -> and certainly will broaden your view

7071.35 -> of the history of and the applications of salt

7074.23 -> as it relates to a great number

7076.52 -> of health and performance metrics.

7078.44 -> We also talked about the perception of salt,

7080.79 -> meaning the perception of salty tastes

7082.81 -> and how the perception of salty tastes

7084.4 -> and the perception of other tastes, like sweet,

7086.62 -> can interact with one another

7088.26 -> to drive things like increased sugar intake

7091.18 -> when you're not even aware of it,

7092.76 -> and indeed, how the combination of salty and sweet taste

7096.54 -> can bias you towards craving more,

7099.22 -> for instance, processed foods,

7100.63 -> and why that might be a good thing to avoid,

7102.83 -> and, of course, we talked about salt

7104.68 -> and its critical role in the action potential,

7107.26 -> the fundamental way

7108.093 -> in which the nervous system functions at all,

7110.5 -> so my hope for you, in listening to this episode,

7113.07 -> is that you consider a question,

7115.3 -> and that question is

7116.42 -> what salt intake is best for you?

7119.56 -> And that you place that question

7121.1 -> in the context of your fluid intake,

7124.16 -> you place that in the context of the diet you're following,

7127.19 -> the amount of caffeine you might be ingesting,

7130.39 -> and the diuretic effects of caffeine,

7132.55 -> and crucially, that you place that in the context

7135.7 -> of the electrolytes, more generally,

7138.16 -> meaning sodium, potassium, and magnesium.

7141.35 -> Someday, there will be an online program

7143.82 -> or an app, I imagine,

7145.26 -> where one could put a bunch of different parameters in

7148.93 -> about their particular health status,

7152.6 -> their particular diet, their particular exercise, et cetera.

7155.47 -> Maybe it would all be run by AI algorithm or something

7158.34 -> where it would monitor all of that for us,

7160.07 -> and then it would spit out for us

7161.97 -> a precise amount of sodium that we should take in each day.

7165.79 -> Unfortunately, no such tool or device exists right now,

7169.41 -> and so all of us have to figure out

7172.06 -> the appropriate amount of sodium intake for ourselves,

7174.92 -> and that has to be done

7176.4 -> under these contextual considerations.

7179.3 -> Who knows?

7180.133 -> Maybe one of you will design such an app or such a device.

7182.34 -> I think it would be very useful.

7185.39 -> If nothing else,

7186.95 -> today's discussion ought to illuminate the fact

7189.71 -> that some strict recommendation of salt intake

7193.92 -> cannot be made universally across the board for everybody.

7196.82 -> There's just simply no way that could be done,

7199.41 -> and yet, I think most of what we've learned about salt

7203.29 -> in the general discussions around health

7205.72 -> are that it's this evil substance.

7207.98 -> Nothing could be further from the truth.

7209.38 -> It's an incredible substance.

7211.01 -> Our physiology is dependent on it.

7213.51 -> Our cognition is dependent on it.

7216.23 -> Indeed, our mental and physical health

7218.027 -> and our performance in essentially all aspects of life

7220.64 -> is dependent on it,

7222.01 -> and I hope I've been able to illuminate

7223.793 -> some of the beautiful ways

7225.25 -> in which the brain and the bodily organs interact

7227.93 -> in order to help us regulate this thing

7229.7 -> that we call sodium balance,

7231.1 -> and the fact that we have neurons in our brain

7233.21 -> that are both tuned to the levels of salt in our body

7237.55 -> and positioned in a location in the brain

7240.17 -> that allows them to detect the levels of salt in our body

7242.97 -> and to drive the intake of more or less salt

7246.17 -> and more or less fluid and other electrolytes

7248.92 -> really just points to the beauty of the system

7251.5 -> that we've all evolved

7252.79 -> that allows us to interact with our environment

7254.74 -> and make adjustments

7255.76 -> according to the context of our daily and ongoing life.

7259 -> If you're learning from and/or enjoying this podcast,

7261.38 -> please subscribe to our YouTube channel.

7263.28 -> That's a terrific zero-cost way to support us.

7265.72 -> In addition, please subscribe to the podcast

7267.93 -> on Spotify and/or Apple

7270.47 -> and on Apple, you have the opportunity

7272.3 -> to leave us up to a five-star review,

7274.1 -> and you can also leave us a comment.

7275.98 -> The best place to leave us comments, however,

7277.94 -> is on the YouTube channel.

7279.5 -> There, you can make suggestions

7280.73 -> about future podcast guests that you'd like us to interview,

7283.46 -> future podcast topics that you'd like us to cover,

7286.07 -> and, of course, you can give us feedback

7287.78 -> about the content of this or other podcasts.

7290.46 -> We do read all those comments.

7292.62 -> Please also check out our sponsors

7294.03 -> mentioned at the beginning of today's episode.

7295.84 -> That's the best way to support this podcast.

7298.07 -> We also have a Patreon.

7299.51 -> It's patreon.com/andrewhuberman,

7302.43 -> and there you can support the podcast

7304.2 -> at any level that you like.

7305.74 -> During today's episode,

7306.8 -> and on many previous episodes of the Huberman Lab Podcast,

7309.63 -> we discuss supplements.

7311.57 -> While supplements aren't necessary for everybody,

7313.74 -> many people derive tremendous benefit from them

7315.98 -> for things like enhancing sleep and focus and so on.

7320.29 -> One issue with supplements, however,

7321.69 -> is that the quality of supplements varies tremendously

7324.75 -> from one brand to the next.

7326.24 -> For that reason, we've partnered with Thorne, T-H-O-R-N-E,

7329.22 -> because Thorne supplements

7330.98 -> are of the absolute highest quality

7333.12 -> in terms of the ingredients they include

7334.89 -> and the precision of the amounts

7336.41 -> of the ingredients they include,

7337.76 -> meaning what's listed on the bottle

7339.38 -> is what's actually contained in that product.

7342.03 -> They've partnered with all the major sports teams

7343.85 -> and with the Mayo Clinic, so trust is very, very high

7346.59 -> with respect to the quality of Thorne products.

7348.78 -> If you'd like to see the Thorne supplements that I take,

7351.07 -> you can go to Thorne,

7352.03 -> that's thorne.com/u/huberman,

7356.64 -> and you can get 20% off any of those Thorne supplements.

7359.9 -> In addition, if you navigate deeper into the Thorne site

7362.45 -> through that portal, thorne.com/u/huberman,

7365.94 -> you can also get 20% off

7367.72 -> any of the other supplements that Thorne makes.

7370.62 -> If you're not already following Huberman Lab

7372.39 -> on Instagram and Twitter, please do so.

7374.77 -> There, I cover science and science-based tools

7377.23 -> that sometimes overlaps with the content of this podcast,

7380.15 -> but sometimes is distinct from the content of this podcast.

7383.73 -> We also have a "Neural Network" newsletter.

7386.05 -> The "Neural Network" newsletter comes out once a month.

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7411.09 -> some key takeaways, and some resources and tools

7413.54 -> that you won't find anywhere else.

7415.57 -> Thank you once again for joining me today

7417.49 -> to discuss the neuroscience and the physiology around salt

7421.6 -> and its many incredible influences on our brain and body,

7425.18 -> and last, but certainly not least,

7427.56 -> thank you for your interest in science.

7429.2 -> [authoritative music]

Source: https://www.youtube.com/watch?v=azb3Ih68awQ