Iodine is necessary to produce thyroid hormone. A review article appearing in the Lancet (March 28,1998;351:923-924) pointed out the that 1.5 billion people were at risk for brain damage due to lack of iodine. An article in the Journal of Clinical Endocrinology and Metabolism (1993;77(3):587-591) summarized the health problems brought on by iodine deficiency. These include cretinism, goiter, intellectual disability, growth retardation, neonatal hypothyroidism, increased miscarriage, increased perinatal mortality and increased infant mortality. Too much iodine can create hyperthyroidism. There may be a connection between low birth weight and iodine deficiency, according to research appearing in Pediatrics (October, 1996;98(4):730-734). Research appearing in the American Journal of Clinical Nutrition (2009; 90(5): 1264-71) looked at iodine status and its relationship to brain development. The subjects were 184 children (between the ages of 10 and 13) with mild iodine deficiency. In the randomized, placebo-controlled study, the subjects were given either 150 mcg of iodine or a placebo each day for a period of 28 weeks. Those given the iodine had improved iodine status and improvement on two of four cognitive tests. Research appearing in the American Journal of Clinical Nutrition (May, 1996;63(5):782-786) found a connection between low iodine levels in children and slow learning.
Iodine supplementation may be useful in the treatment of fibrocystic breast disease. The Canadian Journal of Surgery (October 1993;36:453-460) found that women supplemented with iodine had greater improvement in their symptoms when compared to controls. Earlier animal research appearing in the Archives of Pathology and Laboratory Medicine (November, 1979;103:631-634) looked at rats who were given sodium perchlorate. Sodium perchlorate blocks iodine and the researchers were able to mimic iodine deficiency in the rats–creating fiborcystic breast disease in the rats.
Iodine is an important nutrient. It is especially important to pregnant women and children. Iodine is classified chemically with the halogens–it is similar to fluorine, bromine and chlorine. These other halogens can displace iodine; so drinking water with fluorine and chlorine may increase the need for iodine. Bromine is used in preservatives, like borminated vegetable oil (BVO), and should be avoided. Iodine requirements are 150 mcg per day for adults and 200 mcg per day for pregnant and lactating women. Some physicians believe that these numbers are too low.