I put salt on everything. I have about seven kinds at home: Guérande, fleur de sel, Himalayan, volcanic salt. I put a pinch in my water, especially when I'm fasting, and some in my gym water bottle, alongside baking soda and creatine.
In Take a Breath, I wrote that salt has its own story, and that it is not the villain you were told it was. Here is that story.
Why the IV is salt water.
The bag they hang beside a hospital bed is saline: 0.9 percent salt, 9 grams per liter. It goes back to 1832. A cholera epidemic was killing people across Britain, and cholera kills by draining the body of water and salt. A doctor in Leith, Scotland, named Thomas Latta tried something nobody had done: he put salt water straight into a patient's veins. He published the results in The Lancet that same year.
A century and a half later, doctors found you don't even need a needle. A little salt and sugar in water, taken by mouth, pulls water into the body through the gut, because sugar helps carry the sodium across, and water follows. In 1978 The Lancet called it "potentially the most important medical advance this century." That drink, oral rehydration solution, has saved millions of children.
Here is why it works. Sodium is what keeps water in your blood. It carries the signals in your nerves and makes your muscles contract. Your body cannot run without it.
When you need more.
Some people need more salt than the guidelines suggest. When you fast, your kidneys release more sodium, which is why a pinch in your water helps on fasting days and why people starting a low carb diet feel the "keto flu." Coffee pushes sodium out too.
Andrew Huberman, who gave a whole episode to salt, notes that people whose blood pressure drops when they stand up are often told to eat more of it. One of these conditions is POTS, where the heart races every time a person stands up. In a study at Vanderbilt and the University of Calgary, a week of high salt raised blood volume in people with POTS and calmed their racing heart.
Too much plain water can work against you. At the 2002 Boston Marathon, 13 percent of runners tested at the finish had too little sodium in their blood. The main cause was drinking too much plain water during the race, which watered down the salt in their blood.
How much.
For most people the question is not whether to eat salt but how much. The World Health Organization suggests under 2,000 milligrams of sodium a day, about 5 grams of salt, just under a teaspoon. The average adult eats more than twice that, and most of it never touches a shaker. In Canada, 77 percent of the sodium people eat comes from processed and packaged food: bread, deli meats, sauces, soups and snacks. People also react differently. About half of people with high blood pressure are salt sensitive, and about a quarter of people with normal blood pressure.
Salt needs potassium.
Sodium has a partner, and it is potassium. The two work as a pair: sodium holds water in your blood, and potassium helps your kidneys let the extra sodium go. Most of us eat too much of the first and too little of the second.
Researchers at Harvard measured what more than 10,000 adults were really eating, from repeated 24 hour urine samples, and followed their hearts for years. The more sodium people ate, the higher their risk of heart disease. The more potassium they ate, the lower it was. Every extra 1,000 milligrams of sodium a day raised the risk by 18 percent. Every extra 1,000 milligrams of potassium lowered it by 18 percent.
Then a trial in 600 villages in rural China tested the pair directly. About 21,000 people swapped their usual salt for a salt that was three quarters regular salt and one quarter potassium. They still salted their food. Over almost five years, they had 14 percent fewer strokes and 12 percent fewer deaths than the people who kept regular salt. Salt was never the villain on its own. Salt without potassium is the problem.
The three electrolytes.
You have probably heard about electrolytes. They are minerals that carry an electric charge in your body, and they run your nerves, your muscles and your heartbeat. The main three are sodium, potassium and magnesium. Sodium is easy to get. The other two are where most people fall short.
Rhonda Patrick points out that less than 2 percent of American adults reach the recommended daily potassium. Potassium comes from food: an avocado has about 700 milligrams, a baked potato about 610, a cup of beans about 600, a banana about 420.
Magnesium is just as important, and more than half of Americans don't get enough of it from food. The best food sources are pumpkin seeds, chia seeds, almonds, spinach, cashews and black beans. That makes a supplement worth adding: it matters too much to leave to chance. Magnesium will get its own Lab Note.
Sea salt or table salt.
Table salt is refined until it is almost pure sodium chloride, and in Canada, iodine must be added to it. Sea salts and rock salts, like Guérande, fleur de sel and Himalayan, are less refined and keep traces of other minerals.
Traces is the right word. In 2020, Australian researchers tested 31 pink salts. A teaspoon gave between 1 and 5 percent of a day's magnesium, calcium or potassium. To get a meaningful amount, you would need about six teaspoons a day, about six times the sodium limit. The minerals in salt are a bonus, not a supplement. Get your potassium from food, and your magnesium from food or a supplement.
The one thing sea salts lack is the iodine added to table salt. If they are all you use, get your iodine from seafood, eggs or dairy.
What you should do.
Salt the real food you cook, and cut back on packaged food, which is where most of the sodium hides. Eat potassium every day. Add a pinch of salt to your water when you fast or sweat a lot. Bring the potassium.
Georges
Usually one Experiment on Sunday. Lab Notes in between. Free.
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You had me until you mentioned neuroscientist and snake oil salesman Huberman. He is credible explaining his neuroscience but many of his other opinions are based on over-confidence and commercial interests. He often presents preliminary findings as established science.