A neuroscientist reveals how salt consumption impacts brain function and the body’s fluid balance
Sodium is often blamed in diet debates, but it is also a key component of how the brain and body work. Andrew Huberman, a professor of neurobiology at Stanford University and host of the Huberman Lab podcast, has discussed this on the Huberman Lab podcast. Clips from the podcast (available on YouTube/@hubermanlab) explain why we need sodium and where it can cause problems when taken in the wrong amounts.
How sodium keeps neurons and fluids ticking
Huberman notes that sodium is essential for neurons to communicate properly. The action potential (the electrical signal neurons use) depends heavily on sodium to function. Sodium also helps keep a balance with other electrolytes, like potassium and magnesium, which are needed for organs such as the kidneys and the brain to work well.
The brain monitors sodium levels through a specialised area called the organum vasculosum of the lamina terminalis. This region lacks the usual blood–brain barrier, so it can detect changes in blood sodium and blood pressure. Those detections trigger hormone responses, including the release of vasopressin, which tell the kidneys to retain or release water as required. It is a finely regulated system that requires careful sodium balance.
Thirst: the two types and sodium’s part in them
Huberman points out there are two main kinds of thirst. Osmotic thirst comes from high salt concentrations, while hypovolaemic thirst is triggered by a drop in blood pressure. Both drive us to seek water and salt, showing how sodium and water work together to maintain fluid balance.
Keeping sodium in the right range matters because both too much and too little are risky. Excess sodium inside brain cells can cause swelling and damage, while too little can harm cellular and nerve function. Huberman also refers to “dozens or even hundreds of quality studies” showing the harmful effects of high-salt diets on several organs, including the brain.
Adjusting your salt intake: who needs what
Given the risks of too much salt, Huberman gives a general upper limit of 2.3 grams per day to lower cardiovascular risk. He makes clear that individual needs can vary a lot depending on blood pressure, activity levels and diet.
- For instance, people with orthostatic disorders may need as much as 10 grams of salt per day, though any changes of that magnitude should be made under medical supervision.
- Likewise, people on low-carbohydrate diets often need more sodium and potassium because they lose more minerals, while those eating high amounts of carbohydrates may need less.
Processed foods and how they alter salt perception
Combining salt with sugar and artificial flavourings (especially in ultra-processed foods) can disrupt natural appetite and satiety signals. Humans have salt sensors on the tongue and in parts of the digestive tract, and stimulation of those sensors sends signals to the brain. The potent mix of ingredients in industrial foods can make it hard to gauge how much we are eating and can encourage overeating.
Prioritising whole, minimally processed foods helps keep sodium levels in check and ensures a better balance of potassium and magnesium. As Huberman suggests, any dietary adjustments should be personalised, taking into account other electrolytes and overall fluid balance.
Andrew Huberman’s observations describe the multiple roles sodium plays and why a nuanced approach to diet is useful. By recognising the balance between sodium and other electrolytes, people can make more informed choices and better understand how different diets affect their health.