Less salt, sharper mind

How reducing sodium affects your cognitive performance.

May 11, 2025

Getting enough salt in our diet is absolutely essential in order for our nervous systems to function correctly. Our nerves are essentially electrical transmitters: when they receive a stimulus, they send an electrical pulse to the next neuron in our body, usually ending up at the brain. These electrical impulses are driven by sodium ions: as they move across the membranes of our neurons, they trigger an action potential, which generates the electrical signal.1

Without sodium, our neurons cease to function properly, and we can no longer control our muscles or manage basic autonomic functions like keeping our hearts pumping. Maintaining a proper balance of sodium is therefore quite literally a life-or-death matter. Our brains constantly monitor our sodium levels, and if they drop too low, it triggers the release of aldosterone, which causes a craving for salt.

Our need for salt is also tied in to our limbic systems and our reward systems: some of the most primitive parts of our brains. Too little salt triggers the amygdala to send emergency override messages, telling us to stop whatever we’re doing and seek out salt urgently at all costs.2 And when we get that salt, it activates the lateral hypothalamus, which triggers dopamine and makes us feel good.

The dangers of too much salt

However, too much of the stuff can be dangerous as well. When the sodium concentration in our bodies is too high, that disrupts the smooth functioning of our nervous system.

In the short term, the body tries to dispose of the excess sodium through the kidneys and urine. This, however, can cause dehydration and brain fog, as the fluid balance in your brain and body is disrupted by the extra urination: common symptoms include headaches, confusion, memory problems, mood swings, and the inability to focus. Fortunately, the solution is easy: just drink something. (This is why peanuts and beer are such a great combination: the beer makes you want to eat peanuts, and the salty peanuts make you thirsty.)

But that's not all. In the long term, excess salt can cause a range of physical and mental damage.3 Excess sodium damages the endothelial cells which line blood vessels in the brain: this can impair the blood flow within your brain, which increases your risk of stroke.4 In addition, blood vessels in the hypothalamus constrict, resulting in a decrease in blood flow and a decrease in oxygen supply (hypoxia) to that part of your brain.5

It can also lead to changes in the tau proteins,6 resulting in an increased risk of neurodegenerative diseases such as Alzheimer's, as well as inflammation in the brain,7 which can affect memory, perception, and cognitive ability.8

And, as most of us are painfully aware by the time we reach middle age, salt raises your blood pressure, and is one of the primary causes of hypertension and heart attack.

So how much should we eat?

The short answer is, not a lot. In order to survive, we need somewhere between 500 and 1500 mg of sodium per day, depending on age, gender, physical activity, and weight.9 To put that in perspective, that's about a quarter of a teaspoon of salt per day for most adults.

Doctors and health authorities recommend a maximum of 2,300 mg per day (just under one teaspoon) in order to minimize the health risks, while those of us with blood pressure issues should aim for about no more than half of that.

However, 90% of consume significantly more than that. The average American consumes around 3,400 mg of sodium per day:10 50% more than the recommended maximum, and more than triple what they actually need to survive.11

Where does all this salt come from?

We tend to get our salt from two sources. We sprinkle it on our food as a condiment, but most of it is already in our food before it even reaches our plate.

A lot of home-cooked food is high in salt. It's not uncommon to see recipes calling for a couple of teaspoons of salt to be added to both sweet and savory dishes. If you look at old cookbooks, you’ll notice that the amount of salt in modern recipes is typically around double what was normal fifty or a hundred years ago. And of course, as portion sizes have grown, that’s had an impact on our sodium intake as well: twice as much salt in our food, and twice as much food on our plate means four times as much salt in our bodies.

However, by far the greatest proportion of most people's salt intake comes from prepared foods. Manufacturers routinely add salt to everything from ready-made meals to sauces, soups, pizzas, desserts, cured meats, bread, and pasta - and that doesn't even begin to address the massive industry in salty snacks, chips, pretzels, nuts, and so on.

A single portion of chips typically contains 10% of the daily sodium allowance. That doesn't sound too bad, until you realize what this really means.

For a start, that single portion of chips is typically just 10 chips. A bag of chips often contains eight or more portions, so if you eat the whole bag, you've actually had 80% of your daily allowance. And that allowance doesn't represent the recommended amount of sodium, it's the recommended maximum, which as we saw earlier, is roughly double what you should be aiming for, and almost five times what you actually need. So that bag of chips is giving you four times as much sodium as your body needs for the day, and around 50% more than is healthy. (And let's face it, that's highly unlikely to be your only source of salt during the day.)

Cutting down on salt

Reducing your salt intake to to 1500 mg or less per day can have a wide range of beneficial effects.

For a start, reducing your blood pressure will reduce anxiety and stress very rapidly, as well as massively reducing your risk of heart attacks or stroke. You’ll put less stress on your kidneys and improve the fluid balance throughout your body, which in turn will improve cognitive function, memory, and long-term brain health. Eating less salt can also affect your gut biome by promoting healthier microbial diversity, decreasing inflammation, and improving metabolic health. That in turn can boost your immune system, give you more energy, and aid digestion.12

Adjusting to a lower salt diet can be hard: it’s like dealing with any other addiction. As I mentioned above, your brain is hardwired to seek out salt, and it's become used to expecting high levels of the stuff. When sodium levels drop too low or too rapidly, it can cause hyponatremia, a potentially dangerous condition with symptoms like headache, nausea, confusion, lethargy, mood swings, and in severe cases, seizures.13

At first, food may taste bland and unsatisfying, and you will probably find that you have cravings for salty snacks. These typically pass in a couple of months, once your body and your taste buds have had time to adjust to get used to lower levels of salt. After a while, you will almost certainly find that the majority of ready-made foods or restaurant meals are far too salty for you.

That can be extremely inconvenient, but it's a good sign. It's your body telling you that it's had quite enough salt, thank you, and you really don’t need any more.14

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