"In an estimated two-thirds of households on Earth, table salt is iodized. However, this still leaves an estimated two billion people iodine-deficient. Iodine is required for the essential thyroxin hormones produced by and concentrated in the thyroid gland."
"Iodine deficiency is an important health problem throughout much of the world. Most of the earth's iodine is found in oceans, and iodine content in the soil varies with region. The older an exposed soil surface, the more likely the iodine has been leached away by erosion. "
"A 1/4 teaspoon of iodized table salt provides 95 micrograms of iodine. A 6-ounce portion of ocean fish provides 650 micrograms of iodine. Most people are able to meet the daily recommendations by eating seafood, iodized salt, and plants grown in iodine-rich soil. When buying salt make sure it is labeled 'iodized'."