There are two iodine deficiency disorders (IDD): goiter and cretinism. Goiter is a painless deficiency condition that results from the enlargement of the thyroid to help increase its ability to take up iodine. A couple of pictures of goiter are shown below.
A more serious consequence of iodine deficiency occurs during pregnancy to the fetus. Iodine deficiency during this time can lead to the mental and physical retardation known as cretinism. This condition is characterized by severe hypothyroidism, stunted growth, speech loss, and paralysis3,4. The following links show some examples of individuals with cretinism.
The World Health Organization calls iodine deficiency “the world’s most prevalent, yet easily preventable, cause of brain damage5.” By saying it is easily preventable, they are referring to the ability of salt iodization to prevent brain development problems. The following New York Times article talks about how salt iodization may be the cheapest way to raise the world’s IQ.
Iodine toxicity is rare, but like iodine deficiency, it can result in thyroid enlargement, and hypothyroidism or hyperthyroidism. Acute toxicity results in gastrointestinal irritation, abdominal pain, nausea, vomiting, and diarrhea6.
References & Links
3. Stipanuk MH. (2006) Biochemical, physiological, & molecular aspects of human nutrition. St. Louis, MO: Saunders Elsevier.
4. Shils ME, Shike M, Ross AC, Caballero B, Cousins RJ, editors. (2006) Modern nutrition in health and disease. Baltimore, MD: Lippincott Williams & Wilkins.
6. Gropper SS, Smith JL, Groff JL. (2008) Advanced nutrition and human metabolism. Belmont, CA: Wadsworth Publishing.
Cretinism – http://www.gsi.ir/Images/MedicalGeology/cretinism1.jpg
In Raising the World’s I.Q., the Secret’s in the Salt – http://www.nytimes.com/2006/12/16/health/16iodine.html?_r=1&pagewanted=all