Iodine is a major component of the thyroid hormones, thyroxine (T4), and triiodothyronine (T3). They are based on the amino acid tyrosine. T4 contains four iodine atoms and T3 three iodine atoms. The only known function of iodine is for the production of the thyroid hormones. Excess iodine is secreted in the urine.
Thyroid hormones are required for normal growth and development of the brain and central nervous system. It is required for energy production and oxygen consumption in cells and the maintenance of the metabolic rate.
The regulation of thyroid hormone synthesis, release, and action is a complex process involving the thyroid, the pituitary, the brain, and peripheral tissues.
Sea foods and iodine added to table salt are the highest contributors of iodine to our diet.