An insufficient quantity of iodine and essential constituents of thyroxine (T4) and triiodothyronine (T3), which are necessary for normal growth and development. The sensitivity of different organs to iodine deficiency varies, with the brain being particularly susceptible during the fetal and early postnatal period, and if severe enough, leading to endemic cretinism (if diagnosed in the early stages, it can be corrected with iodine supplementation), or mental deficiency (as formulated by IQ), deaf-mutism and spastic diplegia. Later effects are growth failure and retardation of bone growth. Insufficient iodine most strikingly results in hypothyroidism and goiter (thyroid enlargement, as well of neck and larynx. See figures below). If it is less severe, it can also give rise to hypothyroidism, and goiter, but perhaps surprisingly so hyperthyroidism (a condition characterized by appetite fluctuations, rapid heart beat and weight loss. In contrast, if there is excessive iodine intake is also associated with hyperthyroidism and goiter. World-wide, some 50 million children are adversely affected by iodine deficiency. In countries like the US, iodine deficiency is on the increase then. It re-emergence has been thought to be due to: increased commercially-prepared foods (most made with non-iodized salt), the reduction if the use of sanitizers containing iodine in the dairy industry, and less salt being used in home-cooked foods due to health warnings about the dangers of consuming too much salt in one’s diet.
