In the developed world Iodine deficiency has shown a four-fold increase in the last 40 years. It is safe to say that three quarters of the population does not consume enough iodine to maintain good health. Iodine deficiency is linked heart disease, mental impairment, obesity, psychiatric disorders, and breast cancer as well as other cancers.
Iodine itself is fairly rare in the environment but is found in large quantities in the oceans. Since it is not often found in soil, those who live in inland areas are almost always deficient unless they regularly consume seafood or supplement iodine in their diets.
Relatively rare now, goiter was common more than 100 years ago. Due to lack of iodine the thyroid gland in the neck would swell causing large lump around the throat and neck. In the 1920’s it was discovered that iodine supplementation could prevent goiter and enlarged thyroid. Morton Salt began adding iodine to their commercial salt in 1924. Recently the FDA tested table salts in the US and found that many companies were not adding iodine to their product. In addition, many Americans have reduced their salt intake due to blood pressure concerns which has often led to an iodine deficiency.
Recent studies have shown that aside from thyroid health promoted by iodine, breast tissue is iodine dependent and iodine deficient tissue has been shown to cause alterations in DNA. Also demonstrated is an increase in estrogen receptor proteins. Especially at risk are post-menopausal women. Low iodine levels have been linked to breast cancer and fibrocystic disease in this population.
Researchers have compared Japanese women who typically have a diet rich in iodine (about 25 times higher) than Western women. Breast cancer occurs in Japanese women at one third the rate of those in the West. While the U.S. recommended daily dietary intake of iodine is 150 to 290mcg, a tolerable upper limit is 1,100 mcg.
Fortunately, the solution to iodine deficiency is fairly simple.
Be sure to use iodized salt. Himalayan (pink) typically has no added iodine and naturally contains very little iodine. The same applies to Kosher salt.
Add iodized salt directly to your food. Cooking lowers the iodine content.
If you exercise be aware that you lose iodine through excess perspiration.
Eat foods high in iodine such as seaweed or seafood from the ocean (not lakes rivers and streams).
Take supplemental iodine. This is probably the most consistent way to get enough iodine into your system.
As always, be sure to discuss any supplements with your health care provider.