The body does not make iodine, so it is an essential part of your diet. In addition, this mineral is needed for the production of thyroid hormones. As an integral part of thyroid hormones it regulates body temperature, metabolic rate, reproduction, growth, blood cell production, nerve and muscle function and more. By controlling the rate at which the cells use oxygen, these hormones influence the amount of energy released when the body is at total rest. Approximately 70 to 80% of the body’s iodine is found in the thyroid.