Iodine deficiency
Iodine is a natural requirement of our diets.
Iodine deficiency can lead to inadequate production of thyroid hormone from the thyroid gland (hypothyroidism).
For example, in some parts of Zaire, Ecuador, India, and Chile, remote, mountainous areas, such as in the Alps (in the past), Andes and the Himalayas have a particular predisposition to severe iodine deficiency, goiter, and hypothyroidism.
Since the addition of iodine to table salt, iodine deficiency is rarely seen in the United States