The only major role of Iodine is to serve as an essential part of the basic structure of thyroid hormones. Since the late 1950's Iodine has been used as a bleaching agent for white flour and Iodine deficiency in this country is rare. It is not unusual for individuals immigrating to the U.S. to develop thyroid disease due to the increase in dietary iodine compared to their country of origin. Iodine supplementation in areas that are normally iodine deficient has led to an increase in various types of thyroid diseases including Grave's Disease, Hashimoto's Thyroiditis, and thyroid nodules. It is possible for susceptible individuals to develop thyroid nodules after taking kelp tablets which are rich in iodine.