Iodine is a trace mineral and essential nutrient. In its natural state, it is grayish-black in color and lustrous in appearance. Iodine plays a crucial role in the normal function of the thyroid gland. It is also essential for the production of thyroid hormones, which in turn are necessary for maintaining normal cell metabolism.
Iodized salt is the primary food source of iodine.
Dairy products and vegetables grown in iodine-rich soil also contain large amounts of the mineral. However, people who avoid dairy products, seafood, processed foods and iodized salt can become deficient. Iodine deficiency can lead to decreased thyroid function, goiter, and cretinism, a condition marked by dry skin, swelling around the lips and nose, and impaired mental function. In addition to being linked to iodine deficiency, some studies suggest that goiter may also be caused by excessive iodine intake. Other studies have linked high amounts of iodine to an increased risk of thyroid cancer.