Iodine I Atomic Number: 53 Atomic Weight: 126.9 ______________________________________________________________________________ Human Physiology: - Essential for thyroid hormone - Regulation of metabolism - Need 120-150mcg/day Prevalence: " Exists mostly in the ocean Deficiency: - Goiter (enlargement of thyroid) - Fatigue - Slow metabolism, increased weight, cold intolerance Excess: - Nervousness - Irritability - Tremor - Increased sweating - Weight loss - Graves disease (goiter, protruding eyes) Sources: - Exists in most foods in small quantities - Iodized salt