The case for iodized salt

Imagine how just over 100 years ago, nearly one-third of people in the upper Great Lakes and upper Midwest regions walked around with a goiter on their neck. A goiter is a lump on the throat, which could be as big as an orange, a grapefruit or larger. Actually an enlargement of the thyroid gland, a goiter can come from an overactive thyroid gland, an under-active thyroid gland or an autoimmune condition, but in the United States before the 1920s, the reason was almost always deficiency of iodine. 

iodine is required for making thyroid hormones. In addition to having a goiter, those with iodine deficiency may be fatigued, slow moving or have poor concentration. iodine is even more important for brain development for a fetus during pregnancy and for the growing brains in young children. iodine deficiency can cause fewer IQ points. The archaic term cretinism refers to iodine deficiency syndrome from birth and affected people are small, mentally slow and may have an enlarged tongue and thickened skin, among other ailments. Likely 50 million people suffer from iodine-deficient brain damage world wide still today. 

iodine is a trace element on the earth's crust, but factors like glaciers and flooding have caused it to be even more scarce in landlocked areas and more prevalent around coastal areas.  In the coastal areas the iodine makes its way through the food chain. In the "goiter belt," the upper Midwest and upper Great Lakes regions of the United States, and in Switzerland, goiters were common due to the lack of iodine in the diet.

The ancient Chinese knew ingesting seaweed could shrink a goiter. In the early 1800s, a Swiss physician observed ingesting iodine could treat the goiters of his patients. As with many things, it often takes a war to cause change. In World War I, a Michigan physician observed that over 30% of recruits had a goiter and, for many of them, it was big enough to disqualify them from the military. This finally got people's attention. 

In 1917, US physician Dr. David Marine convinced the Akron, Ohio, school board to allow him to perform a study with iodine supplementation. The schoolgirls who received iodine had significantly fewer cases of goiter than the girls who did not. 

Dr. David Cowie, who founded the pediatrics department at the University of Michigan, proposed the US adopt the Swiss practice of adding iodine to common table salt. It took effort, but thankfully the salt companies adopted the practice, and still today we have a cheap, common remedy to help prevent goiter and iodine deficiency throughout the United States.

Andrew Ellsworth, M.D. is part of The Prairie Doc® team of physicians and currently practices family medicine in Brookings, South Dakota. Follow The Prairie Doc® at http://www.prairiedoc.org and on Facebook featuring On Call with the Prairie Doc® a medical Q&A show based on science, built on trust for 21 seasons, streaming live on Facebook most Thursdays at 7 p.m. central.