How much salt do you need to be healthy?

Q.  From what I read, it seems that we all eat too much sodium and need to try to cut back. But can you go too low? Is there a minimum of sodium that you need to be healthy?

A. Interesting question!  Most of the government's recommended daily values (DVs) are for the minimum recommended amounts. For example, the DV for vitamin D is 400IU, meaning that most people should try to get at least 400IU of vitamin D every day to stay healthy.

But because of the health risks associated with over-consumption of certain nutrients, such as sodium, cholesterol, and saturated fat, the DVs for these nutrients represent the maximum recommended intake. The DV for sodium is 2400mg, meaning that most people should limit their sodium intake to 2400mg per day or less to stay healthy.  People with high blood pressure are often advised to restrict their sodium intake even further, to 1500mg per day or less.

But a certain amount of sodium is essential for your health. The USDA estimates that you need about 1500 mg of sodium (which is not that much less than the recommended maximum!) but this is based both on the amount of sodium you lose every day through perspiration as well as the amount of sodium you need to eat in order to get enough of other minerals that generally "ride along" with sodium in foods. 

For example, iodized salt is the primary source for iodine in the American diet. So restricting salt too much (or using un-iodized salt) may lead to iodine deficiency, which is being investigated as a possible culprit in ADHD.

Assuming that intake of other minerals is sufficient, the amount of sodium it would take to prevent sodium deficiency is probably closer to 500 to 1000mg (depending on how active you are and how much you sweat). Amounts in excess of this are eliminated through the urine.

The average sodium consumption in the U.S. is 3375mg per day, so, obviously, few us us are in danger of sodium deficiency.

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By the way, the Daily Values (which you see on the nutrition facts label for all packaged foods and on every food analysis page on Nutrition Data) are very general. They represent an average figure that will work for most people in the population.  Our Daily Needs Calculator can supply recommendations that have been tailored to your age, gender, and weight.  You can then automatically save these personalized recommendations to your Preference Settings as your Individual Daily Values (IDVs). 

See also these related posts:
The Debate over Salt Continues
Are American Diets Too High in Salt?
Does a Low-Sodium Diet Provide Enough Iodine?