Do I Need to Use Iodized Salt?

Reader Contribution by Linda B. White and M.D.
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“Do I need iodized salt in my diet?”

Without knowing your location or diet, my answer is a qualified “yes.”

We obtain iodine from food grown in soils that contain it, but large areas of the world’s soils lack sufficient iodine. So, seasoning your food with iodized salt is the best way to be sure you’re getting as much of this essential nutrient as you need.

Iodine has one main function in the body: The thyroid gland, a butterfly-shaped gland nestled at the base of the throat, needs it to make thyroid hormones, which affect every cell in the body by regulating metabolism. They’re also critical to optimal growth and development, including that of the skeletal and central nervous systems in fetuses and infants. According to the National Institutes of Health, iodine may also have a positive effect on immune function and in preventing fibrocystic breast disease.

If a person becomes iodine-deficient, his or her thyroid gland will enlarge to form a “goiter.” Other symptoms of an underactive thyroid, called hypothyroidism, include fatigue, constipation, cold intolerance, depression, dry skin and hair, weight gain, and muscle weakness. In 1924, the iodization of table salt in the United States successfully addressed deficiencies caused by the consumption of foods grown in soils lacking in iodine. Before that, illnesses due to iodine deficiency were widespread throughout the Great Lakes, Appalachians and Northwestern regions — known as the “goiter belt.”

If a woman is iodine-deficient during pregnancy, her infant may have mental disabilities, stunted growth, and problems with speech and hearing. In fact, the World Health Organization calls iodine deficiency the most preventable cause of brain damage. Mild iodine deficiency has also been linked with attention deficit disorder.

While the typical U.S. diet contains a lot of salt in the form of processed foods, these foods are mainly made with non-iodized salt, according to the Office of Dietary Supplements. Table salt is thus the main source of iodine in most U.S. diets. (The label will specify whether the salt is iodized.) A half-teaspoon of iodized table salt contains about 140 micrograms of iodine. Adults need 150 micrograms a day. Requirements rise to 220 micrograms during pregnancy and 290 micrograms while nursing.

Reliable dietary sources of iodine include saltwater fish, shellfish and seaweed. Breads and other grains often contain iodine as well.