Iodine

Iodine occurs naturally in seafood, seaweed, and kelp — namely plants and animals found in saltwater. The mineral is also found in milk, meat, spinach, and eggs. The bulk of it in the American diet, however, comes from iodized salt.

The recommended daily dietary allowance of iodine for adults is 150 mcg. In pregnant women, the amount goes up to 220 mcg. And in women who are breastfeeding, it increases to 290 mcg. But rest assured. Getting these amounts is relatively easy. All it takes to reach the RDA for adults is half a teaspoon of iodized salt.

People who have healthy thyroids can eat as much as ten times more iodine than what's recommended and still be fine. But in people who have a thyroid problem, too much iodine is unhealthy. Excess iodine can actually inhibit the production of thyroid hormone, causing goiter and hypothyroidism. And if you already have hyperthyroidism, excess iodine can make your symptoms worse.

Too Little Iodine

The typical U.S. diet these days is rich in iodine. In fact, it's more apt to have too much iodine than it is to be in short supply. Since the 1920s, the nation has enjoyed a plentiful supply of iodized salt. Worldwide, however, the lack of iodine is a common problem, and it remains a massive public health issue on a global scale.

Alert

If you suffer from chronic diarrhea or an illness in which absorption is inhibited, you may have trouble absorbing iodine into your body. In that case, you should have regular thyroid function tests to make sure your body is taking up enough iodine.

But if you're on a low-sodium diet, you may be at risk for not getting enough iodine. Without enough iodine, your body cannot produce the thyroid hormone it needs, and you will be at risk for hypothyroidism and goiter.