Benefits of iodine in your diet

Kristof at the NY Times writes:

Almost one-third of the world’s people don’t get enough iodine from food and water. The result in extreme cases is large goiters that swell their necks, or other obvious impairments such as dwarfism or cretinism. But far more common is mental slowness.

When a pregnant woman doesn’t have enough iodine in her body, her child may suffer irreversible brain damage and could have an I.Q. that is 10 to 15 points lower than it would otherwise be. An educated guess is that iodine deficiency results in a needless loss of more than 1 billion I.Q. points around the world.

One unfortunate consequence of the "heath" trends in the West to choose sea salt over table salt is that the iodine has not been added to sea salt. Deficiencies may result where local soils are deficient in iodine. One scientist observes:

Worldwide, the soil in large geographic areas is deficient in iodine. Twenty-nine percent of the world's population living in approximately 130 countries is estimated to live in areas of deficiency (see Table). This occurs primarily in mountainous regions such as the Himalayas, the European Alps, and the Andes, where iodine has been washed away by glaciation and flooding. Iodine deficiency also occurs in lowland regions far from the oceans, such as central Africa and eastern Europe. Those who consume only locally produced foods in these areas are at risk for IDD.

Wikipedia notes, "The introduction of iodized salt since the early 1900s has eliminated this condition in many affluent countries; however, in Australia, New Zealand, and several European countries, iodine deficiency is a significant public health problem."

As for natural sources of iodine, artist-blogger Kylie Budge writes, "I didn't know about iodine in seaweed until I lived in Japan where people eat many different kinds of seaweed every day. I've grown to love eating seaweed through nori, kombu, hijiki and wakame in Japanese food." If a lack of iodine is correlated with a low IQ, perhaps the success of Japanese at mathematics and other disciplines can be explained by a diet rich in iodine. (Of course, another explination offered is that East Asians get more DHA than other people from the oily fish they eat. Fish oil being a brain nutrient).