Role of Iodine

Recall the discovery of iodine and its use as a means of preventing goiter, a gross enlargement of the thyroid gland in the neck. Iodine is essential for the synthesis of thyroid hormone, which regulates body temperature, reproduction, basal metabolism, growth, and development.

Dietary Reference Intakes for Iodine

Dietary Sources of Iodine

The mineral content of foods is greatly affected by the soil from which it grew, and thus geographic location is the primary determinant of the mineral content of foods. For instance, iodine comes mostly from seawater, so the greater the distance from the sea, the lesser the iodine content in the soil.

Consuming Too Little Iodine

Low iodine levels, which consequently result in hypothyroidism, have many signs and symptoms including fatigue, sensitivity to cold, constipation, weight gain, depression, and dry, itchy skin and paleness. The development of goiter may often be the most visible sign of chronic iodine deficiency, but the consequences of low levels of thyroid hormone can be severe during infancy, childhood, and adolescence as it affects all stages of growth and development. The thyroid hormone plays a major role in brain development and growth, and fetuses and infants with severe iodine deficiency develop a condition known as cretinism, in which physical and neurological impairment can be severe. The World Health Organization (WHO) estimates iodine deficiency affects over two billion people worldwide and it is the number one cause of preventable brain damage worldwide.^[3]

Consuming Too Much Iodine

Excess iodine consumption, which is generally related to supplementation, also causes the thyroid gland to swell, resulting in goiter. Excess iodine consumption can also result in hyperthyroidism, which may play a role in weight loss, increased heat production, muscular tremors, nervousness, racing heartbeat, and protrusion of the eyes.