Using Salt to Optimize Mental & Physical Performance | Huberman Lab

KEYPOINTS

• 01

  Talk about sodium, not salt

  About 40% of table salt by weight is sodium: one gram of salt contains about 388 mg of sodium. Guidelines and studies usually give sodium amounts, so Huberman converts between the two throughout the episode. For example, the U.S. recommendation of 2,300 mg of sodium is about half a teaspoon of salt.

• 02

  The OVLT is the brain's salt and blood-pressure sensor

  The organum vasculosum of the lateral terminalis (OVLT) is one of the few brain areas without a full blood-brain barrier, so its neurons can sample the blood directly. One group of neurons senses osmolarity, meaning salt concentration. Another group of baroreceptor neurons senses blood pressure. Huberman calls it so essential that if it fails, you are 'effectively dead or dead soon'.

• 03

  Two kinds of thirst

  In osmotic thirst, salty blood activates the OVLT, which signals the supraoptic nucleus. That leads the pituitary to release vasopressin (antidiuretic hormone), which tells the kidneys to hold water while you feel thirsty. In hypovolemic thirst, a drop in blood volume or pressure, such as from blood loss, is sensed by baroreceptors. The kidney then releases renin, generating angiotensin II, which also acts on the OVLT. Low blood volume drives a craving for both water and salt.

• 04

  Vasopressin also affects behavior

  Vasopressin, the same hormone that limits urination, appears in research on pair bonding and monogamy in prairie voles, and some people use it as an aphrodisiac. Huberman says he is not suggesting anyone do that. He warns against using vasopressin or oxytocin nasal sprays unless a doctor prescribes them.

• 05

  The health-risk curve for sodium may be J-shaped

  Huberman highlights a 2011 JAMA study on urinary sodium and potassium excretion. In it, the risk of cardiovascular death, stroke, heart attack and heart-failure hospitalization was low-ish at about 2 g of sodium excreted per day and kept falling until about 4.5–5 g. Above that, risk climbed steeply toward 7–12 g. He cautions that no single study is definitive. The 2.3 g guideline exists partly because hypertension is so common.

• 06

  Know your blood pressure before changing salt intake

  People with hypertension or prehypertension need to be careful and should work with a doctor. By contrast, some people with low blood pressure or orthostatic disorders benefit from more sodium. Huberman stresses that over time, storing excess sodium in tissues is bad for health.

• 07

  Salt appetite is homeostatic, but it adapts

  If your sodium is low, you will tend to crave salty foods, and on a mostly unprocessed diet it is usually reasonable to follow that craving. However, a controlled German study of people eating 6, 9 or 12 g of salt a day, published in the Journal of Clinical Investigation, found that the body adapts. Sodium was stored and released in regular weekly and monthly rhythms, regulated by aldosterone and glucocorticoids. That adaptation is why appetite alone isn't a perfect guide.

• 08

  Low sodium can worsen stress and anxiety

  The adrenal stress system (glucocorticoids such as aldosterone) is tightly linked to salt craving. Animal studies, and some human evidence, suggest low dietary sodium exacerbates anxiety and impairs the ability to meet stressors. Low blood pressure itself can feel like anxiety. Huberman says more studies are needed. He suggests that a slight sodium increase from sea salt in water or salting food, not processed foods, might help some people.

• 09

  Neurons literally run on sodium

  Action potentials depend on sodium rushing into neurons, followed by potassium changes and the sodium-potassium pump restoring the gradient. That is why sodium, potassium and magnesium all matter for mental and physical performance, and why dehydration and electrolyte loss cause brain fog.

• 10

  The gut senses sugar below conscious awareness

  The episode opens with Diego Bohórquez's Duke lab. Its 'neuropod' gut cells detect sugar and signal through the vagus nerve to drive dopamine release and sugar seeking. A February 2022 Nature Neuroscience paper, 'The Preference for Sugar over Sweetener Depends on a Gut Sensor Cell', showed that these cells can tell caloric sugar apart from non-caloric sweeteners. What that means for health is not yet clear.