An iodine-deficient diet is more common than having an excess of iodine in your diet. You only need small amounts of this important mineral for good health. The recommended dietary intake for iodine is 150 mcg per day for adults age 19 and older. The tolerable upper intake for levels of iodine is 1,100 mcg per day for people age 10 and older. Iodine supplements can interact with drugs, including high blood pressure and thyroid drugs and some diuretics.
Iodine
Iodine occurs naturally in foods and it's added to others. Foods rich in iodine include seaweed, cod, low-fat yogurt and enriched white bread. Some bodily functions depend on iodine. Your body uses iodine to make thyroid hormones -- essential for proper metabolism. Iodine may play a part in proper immune response and benefit patients with fibrocystic breast disease, according to the Office of Dietary Supplements. The amount of iodine in food depends in part on the amount of iodine in the soil. Manufacturers iodize table salt -- meaning it's fortified with iodine -- to ensure Americans get enough of this important mineral.
Soy Milk and Seaweed
Researchers theorize excess iodine in the diet as the cause of a series of thyroid dysfunction cases in Australia, according to a report from University of Sydney and published in the October 2010 issue of the "Medical Journal of Australia." Soy milk with kombu -- a type of seaweed rich in iodine -- was the common thread among the cases. Three babies were born with neonatal hypothyroidism linked to excess iodine in the mother's diet. In one case, the mother drank the soy milk. Seaweed soup eaten by the mother was the suspected cause of the other two cases.
Iodine Toxicity
Ingesting more than 1.1 mg per day of iodine can cause chronic toxicity. People who were previously deficient in iodine have a higher risk of developing hyperthyroidism -- overactive thyroid -- as a result of chronic iodine toxicity. Oddly enough, too much iodine also causes hypothyroidism -- an under-active thyroid. Symptoms of ingesting a large amount of iodine include an increase in saliva production, a brassy taste in your mouth and skin lesions resembling acne.
Nuclear Explosions
Communities eating seaweed from parts of the ocean close to nuclear explosions are more likely to have excess iodine in their diet, according to a scientific review by the University of Illinois and published in the June 2004 issue of the journal "Experimental Biology and Medicine." Iodine toxicity can develop, causing hypothyroidism and goiters in some people. Newborns are at the highest risk for developing iodine toxicity.
References
- Merck Manuals; Iodine; August 2008
- "Medical Journal of Australia"; Iodine Toxicity From Soy Milk and Seaweed Ingestion Is Associated With Serious Thyroid Dysfunction; B.A. Crawford, et al.; October 2010
- "Experimental Biology and Medicine"; Iodine Toxicity and Its Amelioration; D.H. Baker; June 2004
- Office of Dietary Supplements: Iodine
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