NUTRITION Q&A
The importance of iodine in salt
BY:HELEN RASMUSSEN, MS, RD, FADA
Q: I just noticed that both my sea salt and my regular "when it rains it pours" Morton® salt packages say that the salt does not contain iodine. Is that important? Is it a worry? Where else should I get iodine and how important is it to my body functioning?A: Iodine is an essential compound found in thyroxine, a thyroid hormone that helps to regulate our body's metabolism. Thyroid hormones, complete with the mineral iodine, are critical for life functions. Lack of dietary sources during pregnancy can result in mental retardation, and iodine deficiency can cause an enlargement of the thyroid gland known as goiter, a condition that occurred in epidemic proportions in the early 1900's in the United States. Research later revealed that this disfigurement seemed to be most prevalent in states that had iodine-poor soil and an iodine-poor food supply. This discovery resulted in the decision in the 1920's, in the United States and Canada, to add iodine to salt, essentially eliminating iodine deficiency disorders.
Our body only needs a very small amount of this mineral-hence iodine belongs in the category of "trace minerals." The Recommended Dietary Allowance (RDA) for adult men and women is 150 micrograms per day. Most healthy adults are able to tolerate excess iodine from food, as reflected in the tolerable upper level (UL) of 1100 micrograms per day for adults set by the National Academy of Science.
We can get 380 micrograms of iodine in one teaspoon of iodized salt, but data regarding how much iodine we get from individual foods is not very complete. Food sources rich in iodine include meat from animals whose feed is iodine-rich, seafood, eggs and baked goods. We also get iodine from unlikely places, such as food colorings, dough conditioners, and even disinfectants and sanitizers used to clean food preparation areas. (The latter are known as "incidental additives" and are regulated for safety and present no known hazard.)