Iodine, Iodine metabolism and Iodine deficiency disorders revisited.

Iodine is a vital micronutrient required at all stages of life; fetal life and early childhood being the most critical phases of requirement. Diet is the sole source of iodine, which in turn is dependent upon the iodine content of water and soil. Iodine is metabolized in the human body through a series of stages involving the hypothalamus, pituitary, thyroid gland and blood. Recent advances in physiology and molecular science have revolutionized our understanding of iodine metabolism at the cellular and sub-cellular level. This in turn has improved our knowledge of Iodine Deficiency Disorders (IDD), their prevention, management and control. This article makes an attempt to revisit this important topic in light of recent advances and provides a comprehensive account of the subject.