From  EWG: Should I use iodized salt?

Question: Is there a reason why my table salt is iodized? I’m not even really sure what that means, but it sounds a little scary, and unnecessary. Should I switch to kosher salt or sea salt?

Answer: Stick with the iodized salt! It’s an important source of iodine, a trace nutrient necessary for proper thyroid function. Severe iodine deficiency is rare in the US, but about one third of women in the US have low iodine levels, which makes them especially susceptible to chemical contaminants that interfere with thyroid function.

One of these chemicals is perchlorate, a component of rocket fuel that has leaked out of military sites and contaminated drinking water in many states. It has also been found in a variety of foods, including many produce items and cow’s milk. The CDC has found perchlorate in every one of almost 3,000 people who they tested, indicating widespread exposure among the US population. In addition, they also found that in the one third of women with lower iodine levels, exposure to perchlorate at levels that are commonly found in food and the environment was associated with significant changes in levels of thyroid hormone. This is especially worrisome for women of childbearing age because the developing fetus is vulnerable to any decreases in maternal thyroid hormone.

Iodized salt is no substitute for aggressive public health protections from thyroid toxins in the environment. The government must step in and take responsibility for cleaning up these contaminants to levels that protect human health.

In the meantime, as little as half a teaspoon of iodized salt per day is enough to maintain healthy iodine levels in most people. People with medical conditions like high blood pressure and congestive heart failure should be careful with their salt intake, and no one should dramatically increase salt intake without first checking with their doctor.

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