More than 60 percent of iodine (EYE-uh-dine) in the body is found in the thyroid (THIGH-royd) gland, located near the throat. Thyroid hormones control energy metabolism, body temperature, reproduction, and growth. Iodine deficiency causes the thyroid to greatly enlarge, a condition known as 'goiter' (GOY-ter). Today, iodine deficiencies are relatively rare. Dairy cattle are fed products containing iodine, which is transferred to their milk. Some bakeries use iodine as a dough stabilizer, which is in the bread. Other dietary sources of iodine include fresh saltwater fish and seafood. Peopleused to eat iodized salt, but this appears to be no longer necessary for most Americans. Some people are sensitive to iodine and break out in a rash if they eat too much of it, and in large amounts, iodine can be poisonous.