Iodine

Definition

An essential micronutrient required for the synthesis of thyroid hormone. The effects of iodine deficiency are known as the Iodine Deficiency Disorders (IDDs) and include hypothyroidism, goitre, loss of IQ and cretinism. However, iodine excess can also be harmful; optimal iodine intakes require a careful balance between deficiency and excess, and there is a U-shaped relationship between iodine intake and thyroid function.