Welcome to Huberman Lab Essentials,

where we revisit past episodes for the

most potent and actionable science-based

tools for mental health, physical

health, and performance.

I'm Andrew Huberman and I'm a professor

of neurobiology and opthalmology at

Stanford School of Medicine. Today we

are going to discuss salt, also referred

to as sodium. Salt has many, many

important functions in the brain and

body. For instance, it regulates fluid

balance, how much fluid you desire and

how much fluid you excrete. Salt also

regulates your appetite for other

nutrients, things like sugar, things

like carbohydrates. We all harbor small

sets of neurons. We call these sets of

neurons nuclei, meaning little clusters

of neurons that sense the levels of salt

in our brain and body. There are a

couple brain regions that do this. And

these brain regions are very very

special. Special because they lack

biological fences around them that other

brain areas have. And the those fences

or I should say that fence goes by a

particular name. And that name is the

blood brain barrier or BBB.

Most substances that are circulating

around in your body do not have access

to the brain. In particular, large

molecules can't just pass into the

brain. The brain is a privileged organ

in this sense. However, there are a

couple of regions in the brain that have

a fence around them, but that fence is

weaker. And it turns out that the areas

of the brain that monitor salt balance

and other features of what's happening

in the body at the level of what we call

osmalerity

at the concentration of salt

reside in these little sets of neurons

that sit just on the other side of these

weak fences. And the most important and

famous of these for the sake of today's

conversation is one called OVLT. OVLT

stands for the organome vasculosum of

the lateral terminalis. the neurons in

that region are able to pay attention to

what's passing through in the

bloodstream and can detect for instance

if the levels of sodium in the

bloodstream are too low if the level of

blood pressure in the body is too low or

too high and then the OVLT can send

signals to other brain areas and then

those other brain areas can do things

like release hormones that can go and

act on tissues in what we call the

periphery in the body for instance have

the kidneys secrete eat more urine to

get rid of salt that's excessive salt in

the body. So let's talk about the

function of the OVLT and flesh out some

of the other aspects of its circuitry of

its communication with other brain areas

and with the body in the context of

something that we are all familiar with

which is thirst. Have you ever wondered

just why you get thirsty? Well, it's

because neurons in your OVLT are

detecting changes in your bloodstream

which detect global changes within your

body. And in response to that, your OVLT

sets off certain events within your

brain and body that make you either want

to drink more fluid or to stop drinking

fluid.

There are two main kinds of thirst. The

first one is called osmotic thirst and

the second is called hypovalmic thirst.

Osmotic thirst has to do with the

concentration of salt in your

bloodstream. So let's say you ingest

something very very salty. Let's say you

ingest, you know, a big bag of I I

confess I don't eat these very often,

but I really like those kettle potato

chips. And I don't have too much shame

about that because I think I have a

pretty healthy relationship to food and

I enjoy them. And I understand that it

will drive salt levels up in my

bloodstream and that will cause me to be

thirsty. But why? Why? Because neurons

in the OVLT come in two main varieties.

One variety senses the osmalerity of the

blood. And when the osmalerity, meaning

the salt concentration in the blood is

high, it activates these specific

neurons in the OVLT. And by activates, I

mean it causes them to send electrical

potentials, literally send electrical

signals to other brain areas. And those

other brain areas inspire a number of

different downstream events. The

consequence of th that communication is

that a particular hormone is eventually

released from the posterior pituitary.

So from the pituitary there's a hormonal

signal that's released called vasop

prein. Vasop prein also goes by the name

antidiuretic hormone.

And

antidiuretic hormone has the capacity to

either restrict the amount of urine that

we secrete or when that system is turned

off to increase the amount of urine that

we secrete. So there's a complicated set

of cascades that's evoked by having high

salt concentration in the blood. There's

also a complicated set of cascades that

are evoked by having low concentrations

of sodium in the blood. But the pathway

is nonetheless the same. It's OVLT is

detecting those osmalerity changes,

communicating to the superoptic nucleus.

superoptic nucleus is either causing the

release of or is releasing vasopressin

antidiuretic hormone or that system is

shut off so that the antidiuretic

hormone is not secreted which would

allow urine to flow more freely. Right?

Antidiuretic means anti- release of

urine and by shutting that off you are

going to cause the release of urine.

You're sort of allowing a system to flow

so to speak. The second category of

thirst is hypoalmic thirst. Hypoalmic

thirst occurs when there's a drop in

blood pressure. Okay. So the OVLT as I

mentioned before can sense osmalerity

based on the fact that it has these

neurons that can detect how much salt is

in the bloodstream. But the OVLT also

harbors neurons that are of the

barrowceptor mechano receptor category.

Now more on barero receptors and mechano

receptors later but barerrow receptors

are essentially a receptor a meaning a

protein that's in a cell that responds

to changes in blood pressure. So there

are a number of things that can cause

decreases in blood pressure. Some of

those include for instance if you lose a

lot of blood right if you're bleeding

quite a lot or in some cases if you

vomit quite a lot or if you have

extensive diarrhea or any combination of

those. Both types of thirst os osmotic

thirst and hypoalmic thirst are not just

about seeking water but they also are

about seeking salt. In very general

terms, salt, aka sodium

can help retain water, but sodium and

water work together in order to generate

what we call thirst. Sodium water work

together in order to either retain water

or inspire us to let go of water to

urinate. So before we can dive into the

specifics around salt and how to use

salt for performance and various

recommendations and things to avoid, we

need to drill a little bit deeper into

this fluid balance mechanism in the

body. And for that reason, we have to

pay at least a little bit of attention

to the kidney. The kidney is an

incredible organ. And one of the reasons

the kidney is so amazing is that it's

responsible for both retaining, holding

on to or allowing the release of various

substances from the body. Basically,

blood enters the kidney and it goes

through a series of tubes which are

arranged into loops. If you want to look

more into this, there's the the

beautiful loop of Henley and other

aspects of the kidney design that allow

certain

substances to be retained and other

substances to be released depending on

how concentrated those substances are in

the blood.

The kidney responds to a number of

hormonal signals including vasopressin

in order to for instance antidiuretic

hormone in order to hold on to more

fluid if that's what your brain and body

need and it responds to other hormonal

signals as well. So it's a pretty

complex organ. So the way the kidney is

designed is that about 90% of the stuff

that's absorbed from the blood is going

to be absorbed early in this series of

tubes. So just to give a really simple

example, let's say that you are very low

on fluid. You haven't had much to drink

in a while. Maybe you're walking around

on a hot day. Chances are that the

neurons in your OVLT

will sense the increase in osmarity,

right? The concentration of salt is

going to be increased relative to the

fluid volume that's circulating. This of

course assumes that you haven't excreted

a lot of sodium for one reason or

another. But that increase in osmalerity

is detected by the OVLT. The OVLT is

going to signal a bunch of different

cascades through the superoptic nucleus

etc. And then vasop prein is going to be

released into the bloodstream. And vasop

prein again also called antidiuretic

hormone is going to act on the kidney

and change the kidney's function in a

couple of different ways. Some

mechanical, some chemical, okay? in

order to make sure that your kidney does

not release much water, doesn't make you

want to urinate and in fact even if you

would try to urinate your body's going

to tend to hold on to its fluid stores.

Okay, so very simple straightforward

example. We can also give the other

example whereby if you're ingesting a

lot a lot a lot of water and it's not a

particularly hot day and you're not

sweating very much. Let's assume your

salt intake is constant or or is low for

whatever reason. Well then the

osmalerity the salt concentration in

your blood is going to be lower. Your

OVLT will detect that because of these

osmo sensing neurons in your OVLT. Your

OVLT will fail to signal to the

superoptic nucleus and there will not be

the release of vasopressin antidiuretic

hormone and you can excrete uh all the

water that uh your body wants to

excrete. Meaning you'll be able to

urinate. there's no holding on to water

at the level of the kidney. Okay. So,

how much salt do we need and what can we

trust in terms of trying to guide our

ingestion of salt? First of all, I want

to be very very clear that there are a

number of people out there that have

prehypertension or hypertension. You

need to know if you have prehypertension

or hypertension. You need to know if you

have normal tension, meaning normal

blood pressure. Everyone should know

their blood pressure is an absolutely

crucial measurement that has a lot of

impact on your immediate and long-term

health outcomes. It informs a lot about

what you should do. Should you be doing

more cardiovascular exercise? Should you

be ingesting more or less salt? And

without knowing what your blood pressure

is, I can't give a one-sizefits-all

recommendation. And indeed, I'm not

going to give medical recommendations.

I'm simply going to spell out what I

know about the research which hopefully

will point you in the direction of

figuring out what's right for you in

terms of salt and indeed fluid intake.

There is a school of thought that

everybody is consuming too much salt.

And I do want to highlight the fact that

there are dozens if not hundreds of

quality papers that point to the fact

that a quote unquote high salt diet can

be bad for various organs and tissues in

the body, including the brain.

It just so happens that because fluid

balance both inside and outside of cells

is crucial not just for your heart and

for your lungs and for your liver and

for all the organs of your body but also

for your brain that if the salt

concentration inside of cells in your

brain go becomes too high, neurons

suffer, right? they will draw fluid into

those cells because water tends to

follow salt as I mentioned before and

those cells can swell. You can literally

get swelling of brain tissue.

Conversely, if salt levels are too low

inside of cells in any tissue of the

body, but in the brain included, then

the cells of the body and brain can

shrink because water is pulled into the

extracellular space away from cells. And

indeed, under those conditions, brain

function can suffer and indeed the

overall health of the brain can suffer.

At fairly low levels of sodium, meaning

at about two grams per day, you run

fewer health risks, but the number of

risks continues to decline as you move

towards four and five grams per day. And

then as you increase your salt intake

further, then the risk dramatically

increases. Most people are probably

consuming more than that because of the

fact that they are ingesting processed

foods and processed foods tend to have

more salt in them than non-processed

foods. But if we are to take this number

of 2.3 grams, that's the recommended

cutoff for ingestion of sodium that

indeed is associated with low incidence

of hazardous outcomes, cardiovascular

events, stroke, etc. So again, I want to

be very very clear that you need to know

your blood pressure. If you have high

blood pressure or you're

prehypertensive, you should be

especially cautious about doing anything

that increases your blood pressure. And

as always, you want to of course talk to

your doctor about doing anything that

could adjust your health in any

direction. But there are a number of

people out there that have low blood

pressure, right? People that get dizzy

when they stand up, people that are

feeling chronically fatigued. And in

some cases, not all, those groups can

actually benefit from increasing their

sodium intake. Why? Well, because of the

osmalerity of blood that we talked about

before, where

if you have a certain concentration of

sodium, meaning sufficient sodium in

your bloodstream, that will tend to draw

water into the bloodstream and

essentially the pipes that are your

capillaries, arteries, and and veins

will be full. The blood pressure will

get up to your head. Whereas some people

their blood pressure is low because the

osmalerity of their blood is low and

that can have a number of downstream

consequences. I should also mention it

can be the consequence itself of

challenges or or even deficits in kidney

function. But all of these organs are

working together. So the encouragement

here is not necessarily to ingest more

sodium. It's to know your blood pressure

and to address whether or not an

increase in sodium intake would actually

benefit your blood pressure in a way

that could relieve some of the dizziness

and other symptoms of things like

orthostatic disorders. Let's look at

what the current recommendations are for

people that suffer from orthostatic

disorders like orthostatic hypo meaning

too low tension orthostatic hypotension

postural tacicardia syndrome sometimes

referred to as POTS Ps or idiopathic

orthostatic tacicardia and syncope those

groups are often told to increase their

salt intake in order to combat their

symptoms. The American Society of

Hypertension recommends anywhere from

6,000 to 10,000. These are very high

levels. So, this is 6 g to 10 gram of

salt per day. Keeping in mind again that

salt is not the same as sodium. So, that

equates to about 2400 to 4,000

milligrams of sodium per day. I point

out this paper and I point out these

higher salt recommendations to emphasize

again that context is vital, right? that

people with high blood pressure are

going to need certain amounts of salt

intake. People with lower blood pressure

are going to need higher amounts of

salt. And for most people out there,

you're going to need to evaluate how

much salt intake is going to allow your

brain and body to function optimally. So

if you're exercising a lot, if you're

particular cold, dry environment or a

particular hot environment, you ought to

be ingesting sufficient amounts of salt

and fluid. A rule of thumb for

exercise-based replenishment of fluid uh

comes from what I uh some episodes back

referred to as the Galpin equation. Uh

the Galpin equation uh I named it

although after Andy Galpin and I think

uh that is the appropriate attribution

there. Andy Galpin is an exercise

physiologist. So the galpin equation is

based on the fact that we lose about 1

to five pounds of water per hour which

can definitely impact our mental

capacity and our physical performance.

And the reason that loss of water from

our system impacts mental capacity and

physical performance has a lot to do

with literally the changes in the volume

of those cells, the size of those cells

based on how much sodium is contained in

or outside those cells. And the formula

for hydration, the so-called galpin

equation is your body weight in pounds

divided by 30 equals the ounces of fluid

you should drink every 15 minutes. Now

the Galpin equation is mainly designed

for exercise, but I think is actually a

very good rule of thumb for anytime that

you need to engage mental capacity, not

just physical performance. The idea is

to make sure that you're entering the

activity, cognitive or or physical,

sufficiently hydrated, and that

throughout that activity, you're

hydrating regularly. And it points to

the fact that most people are probably

underhydrating, but not just

underhydrating from the perspective of

not ingesting enough water that they're

probably not getting enough electrolytes

as well, sodium, potassium, and

magnesium. So, we've all heard about how

excess salt it's bad for blood pressure,

damage the heart, the brain, etc. I do

want to give some voice to situations

where too little salt can actually cause

problems. And this has everything to do

with the nervous system. So, without

getting into excessive amounts of

detail, the kidneys, as we talked about

before, are going to regulate salt and

fluid balance. The adrenal glands which

ride at top the kidneys are going to

make gluccocorticoids like eldoststerone

and those are going to directly impact

things like fluid balance and in part

they do that by regulating how much

craving for and tolerance of salty

solutions uh we have the whole basis for

a relationship between the adrenal

system these gluccocorticoids things

like eldoststerone and the craving for

sodium is that

the stress system is a generic system

designed to deal with various challenges

to the organism to you or to me or to an

animal. And those challenges can arrive

in many different forms.

They can be an infection, it can be

famine, it can be lack of water and so

on. But in general, the stress response

is one of elevated heart rate, elevated

blood pressure, and an ability to

maintain movement and resistance to that

challenge. Okay, it's clear from a

number of studies that if sodium levels

are too low that our ability to meet

stress challenges is impaired. There are

conditions such as when we are under

stress challenge when there is a natural

craving for more sodium and that natural

craving for more sodium is hardwired

into us as a way to meet that challenge.

Now we can't have a discussion about

sodium without having a discussion about

the other electrolytes magnesium and

potassium. I want to emphasize that many

people are probably getting enough

magnesium in their diet that they don't

need to supplement magnesium. Some

people however opt to supplement

magnesium in ways that can support them.

And there are many different forms of

magnesium. And just in very brief

passing, I'll just say that there is

some evidence that you can reduce muscle

soreness from exercise by ingestion of

magnesium malate. M a l a t. I've talked

before about magnesium thrienate. T h r

e n o a t. magnesium thrienate for sake

of promoting the transition into sleep

and for depth of sleep. And then there

are other forms of magnesium, magnesium

bislycinate which is seems at least on

par with magnesium 3 and8 in terms of

promoting transition into and depth of

sleep and so on. There are other forms

of magnesium magnesium citrate which um

has other functions. Actually magnesium

citrate is a is a fairly effective uh

laxative um not known to promote sleep

and things of that sort. So, a lot of

different forms of magnesium and there's

still other forms out there. Many people

are not getting enough magnesium. Many

people are. Okay. So, that's magnesium.

Anytime we're talking about sodium

balance, we have to take into

consideration potassium because the way

that the kidney works and the way that

sodium balance is regulated both in the

body and the brain is that sodium and

potassium are working in close concert

with one another. There are a lot of

different recommendations about ratios

out there and they range widely from 2:1

ratio of potassium to sodium. Uh I've

heard it in the other direction too.

I've heard a 2:1 sodium to potassium. Um

the recommendations vary. Now for people

that are following low carbohydrate

diets, one of the most immediate effects

of a low carbohydrate diet is that

you're going to excrete more water. And

so under those conditions, you're also

going to lose not just water, but you'll

probably also lose sodium and potassium.

And so some people, many people in fact,

find that when they are on a lower or

low carbohydrate diet, then they need to

make sure that they're getting enough

sodium and enough potassium. And of

course, some people who are on low

carbohydrate diets do ingest vegetables,

you know, or other forms of of food that

that carry along with them potassium. So

it's quite variable from person to

person. I mean you can imagine if

carbohydrate holds water, water and salt

balance and potassium go hand in hand in

hand. That if you're on a low

carbohydrate diet that you might need to

adjust your salt intake and potassium

and conversely that if you're on a

carbohydrate- richch diet or a moderate

carbohydrate diet, then you may need to

ingest less sodium and less potassium.

So, up until now, we've been talking

about salt as a substance and a way to

regulate fluid balance and blood volume

and so on. We haven't talked a lot about

salt as a taste or the taste of things

that are salty. And yet, we know that we

have salt receptors, meaning neurons

that fire action potentials when salty

substances are detected. Much in the

same way that we have sweet detectors

and bitter detectors and we have

detectors of umami, the savory flavor on

our tongue. Well, we also have salt

sensors at various locations throughout

our digestive tract. Although that the

sensation and the taste of salt actually

ex exerts a very robust effect on

certain areas of the brain that can

either make us crave more or sate,

meaning fulfill our desire for salt. And

you can imagine why this would be

important. Your brain actually has to

register whether or not you're bringing

in salt in order to know whether or not

you are going to crave salt more or not.

And beautiful work that's been done by

the Zuker lab, Zuker, Zuker lab at

Columbia University, as well as many

other labs have used imaging techniques

and other techniques such as molecular

biology to define these so-called

parallel pathways. Parallel meaning

pathways that represent sweet or the

presence of sweet tastes in the mouth

and gut. Parallel pathways meaning

neural circuits that represent the

presence of salty tastes in the mouth

and gut and so on. And that those go

into the brain move up through brain

stem centers and up to the neoortex

indeed where our seat of our conscious

perception is to give us a sense and a

perception of the components of the

foods that we happen to be ingesting.

the pathways, the parallel pathways for

salty and the parallel pathways for

sweet and bitter and so on can actually

interact. And this has important

relevance in the context of food choices

and sugar craving. One of the things

that's common place nowadays is in many

processed foods there is a business

literally a business of putting

so-called hidden sugars. And these

hidden sugars are not always in the form

of caloric sugars. They're sometimes in

the form of artificial sweeteners into

various foods. And you might say, well,

why would they put more sugar into a

food and then disguise the sugary taste

given that sweet tastes often compel

people to eat more of these things?

Well, it's a way actually of bypassing

some of the homeostatic mechanisms for

sweet. You know, even though we might

think that the more sweet stuff we eat,

the more sweet stuff we crave, in

general, people have a threshold whereby

they say, "Okay, I've had enough uh

sugary stuff." So these sensory systems

interact in this way

by putting sugars into foods and hiding

the sugary taste of those foods. Those

foods, even if they contain artificial

sweeteners, that will then signal to the

brain to release more dopamine and make

you crave more of that food. Whereas had

you been able to perceive the true

sweetness of that food, you might have

consumed less. And indeed, that's what

happens. So these hidden sugars are kind

of diabolical.

Why am I talking about all of this in

the context of an episode on salt? Well,

as many of you have probably noticed, a

lot of foods out there contain a salty

sweet combination. And it it's that

combination of salty and sweet, which

can actually lead you to consume more of

the salty sweet food than you would have

it if it had just been sweet or it had

just been salty. And that's because both

sweet taste and salty taste have a

homeostatic balance. So if you ingest

something that's very very salty, pretty

soon your appetite for salty foods will

be reduced. But if you mask some of that

with sweet, well, because of the uh

interactions of these parallel pathways,

you somewhat shut down your perception

of how much salt you're ingesting. Or

conversely, by ingesting some salt with

sweet foods, you mask some of the

sweetness of the sweet foods that you're

tasting and you will continue to indulge

in those foods. So salty sweet

interactions uh can be very diabolical.

They can also be very tasty, but they

can be very diabolical in terms of

inspiring you to eat more of a

particular food than you would otherwise

if you were just following your

homeostatic salt or your homeostatic

sugar balance systems. So your brain has

a way of representing the pure form of

taste, salty, sweet, bitter, etc., and

has a way of representing their

combinations. And food manufacturers

have have exploited this um to a large

degree. I mention all of this because if

you're somebody who's looking to explore

either increasing or decreasing your

sodium intake for health benefits, for

performance benefits, in many ways it is

useful to do that in the context of a

fairly pure meaning unprocessed food

intake background. Whether or not that's

keto, carnivore, omnivore, uh

intermittent fasting, or what have you,

it doesn't really matter. But the closer

that foods are to their basic form and

taste, meaning not com large

combinations of large amounts of

ingredients, and certainly avoiding

highly processed foods, the more quickly

you're going to be able to hone in on

your specific salt appetite and salt

needs, which as I've pointed out

numerous times throughout this episode,

are going to vary from person to person

depending on nutrition, depending on

activity, depending on hormone status.

So, if you want to home in on the

appropriate amount of sodium for you,

yes, blood pressure is going to be an

important metric to pay attention to as

you go along. But in determining whether

or not increasing your salt intake might

be beneficial for uh for instance, for

reducing anxiety a bit or for increasing

blood pressure to offset some of these

postural syndromes where you get dizzy,

etc. for improving sports performance or

cognitive performance. And indeed many

people find and it's reviewed a bit and

some of the data are reviewed in the

book the salt fix that when people

increase their salt intake in a backdrop

of relatively unprocessed foods that

sugar cravings can indeed be vastly

reduced. And that makes sense given the

way that these neural pathways for salty

and sweet interact. Now, thus far, I've

already covered quite a lot of material,

but I would be completely remiss if I

didn't emphasize the crucial role that

sodium plays in the way that neurons

function. In fact, sodium is one of the

key elements that allows neurons to

function at all. And that's by way of

engaging what we call the action

potential. The action potential is the

fundamental way in which neurons

communicate with one another. The point

I'd like to make, at least as it relates

to this episode on salt, is that having

sufficient levels of salt in your system

allows your brain to function, allows

your nervous system to function at all.

Again, this is the most basic aspect of

nervous system function. And there are

cases where this whole system gets

disrupted. And that brings us to the

topic of sodium and water balance.

As many of you have probably heard, but

hopefully uh if you haven't, you'll take

this message seriously. If you drink too

much water, especially in a short amount

of time, you can actually kill yourself.

All right? And we certainly don't want

that to happen. If you ingest a lot of

water in a very short period of time,

something called hyperetriia,

you will excrete a lot of sodium very

quickly and your ability to regulate

kidney function will be disrupted. But

in addition to that, your brain can

actually stop functioning. And I've

talked about this a bit in the episode

on endurance, but there are instances in

which, you know, competitive athletes

have come into the stadium to finish a

final lap of a long endurance race and

are completely disoriented and actually

can't find their way to the finish line.

You know, it might sound like kind of a

silly kind of crazy example, but there

are examples of people having severe

mental issues and physical issues post

exercise when that exercise involved a

ton of sweating or hot environments or

insufficient ingestion of fluids and

electrolytes because included in that

electrolyte formula, of course, is

sodium. And as you just learned, sodium

is absolutely crucial for neurons to

function. So to briefly recap some of

what I've talked about today, we talked

about how the brain monitors the amount

of salt in your brain and body and how

that relates to thirst and the drive to

consume more fluid andor salty fluids.

We also talked a little bit about the

hormones that come from the brain and

operate at the level of the kidney in

order to either retain or allow water to

leave your system. We talked a little

bit about the function of the kidney

itself, a beautiful organ. We talked

about the relationship between salt

intake and various health parameters and

how a particular range of salt intake

might be optimal depending on the

context in which that range is being

consumed. Meaning depending on whether

or not you're hypertensive,

pre-hypertensive or normal tension. We

talked about fluid intake and

electrolyte intake. So sodium, potassium

and magnesium in the context of athletic

or sports performance but also in terms

of maintaining cognitive function.

Talked about the galpin equation which

you could easily adapt to your body

weight into your circumstances. Of

course adjusting the amount of fluid and

electrolyte intake upwards if you're

exercising or working in very hot

environments downwards maybe if you're

in less hot environments where you're

sweating less and so on. We also talked

about the relationship between the

stress system and the salt craving

system and why those two systems

interact and why for some people who may

suffer a bit from anxiety or under

conditions of stress, increasing salt

intake, provided it's done through

healthy means, might actually be

beneficial. We also talked about

conditions in which increasing salt

intake might be beneficial for

offsetting low blood pressure and some

of these postural syndromes that can

lead people to dizziness and so forth.

These are things that have to be

explored on an individual basis and of

course have to be explored with the

support of your doctor. We also talked

about the perception of salt, meaning

the perception of salty tastes, and how

the perception of salty taste and the

perception of other tastes like sweet

can interact with one another to drive

things like increased sugar intake when

you're not even aware of it. And indeed,

how the combination of salty and sweet

tastes can bias you towards craving

more, for instance, processed foods and

why that might be a good thing to avoid.

And of course, we talked about salt and

its critical role in the action

potential, the fundamental way in which

the nervous system functions at all. So

my hope for you in listening to this

episode is that you consider a question

and that question is what salt intake is

best for you and that you place that

question in the context of your fluid

intake and crucially that you place that

in the context of the electrolytes more

generally meaning sodium, potassium and

magnesium. And I hope I've been able to

illuminate some of the beautiful ways in

which the brain and the bodily organs

interact in order to help us regulate

this thing that we call sodium balance.

And the fact that we have neurons in our

brain that are both tuned to the levels

of salt in our body and positioned in a

location in the brain that allows them

to detect the levels of salt in our body

and to drive the intake of more or less

salt and more or less fluid and other

electrolytes. really just points to the

beauty of the system that we've all

evolved that allows us to interact with

our environment and make adjustments

according to the context of our daily

and ongoing life. And last, but

certainly not least, thank you for your

interest in science.