Harvard Health Letter

In Brief: Is there a downside to low-sodium diets?

In Brief

Is there a downside to low-sodium diets?

We're supposed to limit our daily sodium intake to less than 2,400 milligrams, which is about the amount in a teaspoon of table salt. In return, we cut our high blood pressure risk.

But a Canadian researcher says all the low-sodium admonitions may be having the unintended consequence of lowering iodine consumption.

We need iodine in our diets because the body needs it to make thyroid hormones. In adults, those hormones regulate metabolism and in children, they're critical to mental and physical development. The Recommended Dietary Allowance (RDA) for adults is 150 micrograms a day. Thyroid disease from iodine deficiency used to be a big problem in the United States and many other countries. But the addition of iodine to salt has greatly reduced the problem and is one of the most successful public health interventions ever. In the United States, only table salt is iodized, not the salt used in processed food.

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