Iodine Deficiency Disorders

Key points

• • Iodine is needed to make thyroid hormones, and a lack of it in the diet causes a spectrum of harms called iodine deficiency disorders.
• • The commonest sign is goitre, a swelling of the thyroid gland in the neck as it enlarges to try to trap more iodine.
• • The most serious harm is to the developing baby: severe iodine lack in pregnancy causes congenital hypothyroidism (historically called cretinism), with stunted growth and permanent brain damage.
• • Iodine deficiency is a leading preventable cause of brain damage worldwide, and even a mild lack can lower a child's learning ability.
• • It occurs mainly in hilly and inland regions where the soil and water are low in iodine, so the food grown there is also low in it.
• • It is prevented cheaply and effectively by adding iodine to everyday salt (universal salt iodisation).