Role: As a component of thyroid hormones, it is involved with regulating body temperature, metabolic rate, reproduction, and growth.
Deficiency: Simple goiter is deficiency disease: enlargement of the thyroid gland, cold intolerance, weight gain, sluggishness, decreased body temperature. Cretinism is deficiency disease caused by inadequate iodine intake during pregnancy: mental retardation, stunted growth, deafness.
Sources: Iodized salt; ocean fish and seafood; seaweed; foods produced on iodine-rich soils (usually near an ocean); bread made with dough conditioners; dairy products (if iodine-containing disinfectants are used to clean processing areas).
Toxicity: Toxicity produces goiter.