Iodine is an essential nutrient. Iodine deficiency results in hypothyroidism, detected by low thyroid hormone levels in the blood. Iodine deficiency during pregnancy, breast-feeding and in early childhood causes mental retardation. The Recommended Dietary Allowance (RDA) for iodine for adults is 150 micrograms per day. In the March 2007 issue of "The Journal of Clinical Endocrinology & Metabolism," Dr. Haddow concluded that the U.S. non-pregnant adult population is iodine sufficient.
Multi-Vitamin/Multi-Mineral Dietary Supplements
The Food and Drug Administration classifies supplements as foods. Some of the brand name and store brand multi-vitamin products provide 150 µG of iodine. This is 100 percent of the adult recommended dietary allowance and also 100 percent of the label daily value. Women who are pregnant or breast feeding need more from their supplement or diet, as their RDAs are 220 µG/day and 290 µG/day, respectively.
Iodized Salt
Salt fortification with iodine began in the United States in 1924. Iodized salt is labeled as such, and is an obvious means of increasing iodine intake. However, current health recommendations to reduce salt intake as a means of reducing the risk of hypertension are in opposition to the idea of using more salt on foods to get more iodine. According to product labels, one gram of salt contains 45 µG iodine. Iodization of salt is not mandatory in the United States. The salt in packaged foods such as soups or chips is not iodized, nor is sea salt or kosher salt. Restaurants do not use iodized salt.
Seafood and Seaweed
Ocean-caught fish, squid, shrimp and shellfish are good sources of iodine, typically containing 20 to 80 µG per serving. Edible seaweed can range from 16 µG/gram for nori to more than 4000 µG for some edible kelp varieties. Too much iodine can be bad for your health. The official Dietary Reference Intakes review sets the tolerable upper intake level at 1100 µG/day.
Dairy Foods
The iodine content of dairy foods depends on how much iodine is in the cow feed. Dr. Pearce reported in the July 2004 issue of "Journal of Clinical Endocrinology & Metabolism" that an average for 18 store-bought samples of cow's milk ranged from 88 to 168 µG per 250 ml, with an average of 116 µG/250 ml. That volume is just slightly more than eight ounces.
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