Here's a link to my recent article in Life Extension Magazine on iodine:
Halt on Salt Sparks Iodine Deficiency
Iodized salt, a concept introduced into the U.S. by the FDA in 1924, slowly eliminated goiter (enlarged thyroid glands), along with an enormous amount of thyroid disease, heart attack, mental impairment, and death. The simple addition of iodine to salt ensured that salt-using Americans obtained enough iodine sufficient to not have a goiter.
Now that the FDA, goiters long forgotten from their memories, urges Americans to reduce salt, what has happened to our iodine?
I talk at length about this issue in the Life Extension article.