Iodine Supplementation: A Double Edged Sword

Abstract

In 1811, Courtois serendipitously discovered iodine, when he added sulfuric acid to seaweed in order to extract ammonium nitrate, a substance used to manufacture gun powder for Napoleon’s army. This chemical reaction led to the release and subsequent re-crystallization of a violet vapor [1]. In 1895, Baumann found the presence of this element in the thyroid gland and in 1917; Marine and Kimball linked the development of a goiter to iodine deficiency. Since then, iodine has been identified as being essential to the production of thyroid hormone and hence, essential for mammalian life. Due to the recognition of the morbidity and mortality associated with iodine deficiency, the latter half of the 20th century saw the term “iodine deficiency disorders” being coined, as well as aggressive measures to increase dietary iodine supplementation [2]. Recently, there has been an increasing emphasis in the field of alternative medicine to increase the oral intake of iodine. Some proponents suggest that it can be safely ingested in concentrations 100,000 times the recommended daily allowance (RDA) [3]. However, clinical data and physiological mechanisms, such as the Jod-Basedow phenomenon or the Wolff–Chaikoff effect, demonstrate that excessive exogenous iodine can cause thyroid dysfunction in the form of hyperthyroidism or hypothyroidism [4].