A essential mineral that is an integral part of the thyroid hormones, thyroxin and triiodothyronine which have important metabolic roles and govern basal metabolism. The best known iodine deficiency symptom is goiter. Other iodine deficiency problems are reduced vitality, hypothyroidism, inability to think clearly, low resistance to infection, loss of control of the muscles of the mouth resulting in mouth contortion and drooling, defective teeth, tendency to obesity and cretinism which is a congenital abnormal condition marked by physical stunting and mental deficiency.