Iodine Health Article

Precautions

Too much or too little iodine intake results in a wide spectrum of disorders that are addressed by adjusting iodine intake. Too much iodine can result in toxicity.

Iodine deficiency disorders (IDDs) are preventable, but not curable, by ensuring adequate iodine intake. Only a small amount of iodine is required over the human life span. The body, however, does not store iodine for long periods, so the intake must be regular. Too little iodine intake can result in cold feet, fatigue, insomnia, problems with skin, nails, and hair, and weight gain. Goiter can result from iodine deficiency. Certain substances called goitrogens can also induce goiter by interfering with thyroid functioning. Some foods have goitrogenic tendencies, as do certain drugs, for example, thiourea, sulfonamides, and antipyrine. As listed by Prescriptions for Nutritional Healing and other sources, foods containing substances that can prevent the utilization of iodine when eaten in large quantities include Brussels sprouts, cabbage, cauliflower, kale, millet, mustard, peaches, peanuts, pears, pine nuts, soybeans, and turnips. Limiting consumption of these foods may be recommended for persons with an underactive thyroid.

Iodine deficiency can also result in serious irreversible disorders and, as of May 2000, is considered a major global health problem by organizations such as the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF). According to the International Council on Control of Iodine Deficiency Disorders (ICCIDD), IDDs are the most common cause of preventable brain damage and mental retardation worldwide. IDD results in cretinism (a form of stunted growth) and problems in movement, speech, and hearing. A pregnant woman with an iodine deficiency risks miscarriage, stillbirth, and mental retardation of her baby. As of 1999, the WHO called IDD a significant public health problem in 130 countries. The ICCIDD reported 1.6 billion people worldwide at risk for IDDs, and 50 million children suffering from some degree of IDD. Although not common, iodine deficiency is on the rise in the United States.

In 2002, the United Nation's Children's Fund announced a pledge to eliminate iodine deficiency in the world by 2005, citing the problem as a major cause of psychiatric and learning disabilities.

Side effects

Excess iodine is typically excreted, and output can be measured in the urine. Regular excessive iodine intake is needed for toxicity. Excess iodine, when used as a supplement or in drug therapy, may reduce thyroid function. Although more commonly associated with iodine deficiency, goiter can also result from too much iodine due to thyroid hyperactivity. Additionally, high amounts of iodine from sources such as overuse of iodized salt, vitamins, cough medications, kelp tablets, or from medical testing can cause effects including rapid pulse, nervousness, headaches, fatigue, a brassy taste in the mouth, excessive salivation, gastric irritation, and hypothyroidism. Acne can appear or become worse. Some iodine-sensitive individuals may have an allergic reaction to iodine, often a skin rash. A physician may recommend that high iodine foods be removed from the diet of those who are iodine-sensitive. Similar side effects have also been observed in some women participating in studies on iodine and diagnosed FBD. Radioactive iodine has been implicated in producing thyroid dysfunction and thyroid cancer.

BOOKS

The Merck Manual of Diagnosis and Therapy. 17th ed. Edited by Mark H. Beers and Robert Berkow. Whitehouse Station, N.J.: Merck Research Laboratories, 1999.

National Research Council. Recommended Dietary Allowances. 10th ed. Washington, D.C.: National Academy Press, 1989.

PERIODICALS

"In Case you Haven't Heard." Mental Health Weekly (July 1, 2002): 8.

ORGANIZATIONS

International Council for Control of Iodine deficiency Disorders (ICCIDD). Prof. Jack Ling. Director, ICEC. 1501 Canal Street, Suite 1304, New Orleans, LA 70112. (504)584–3542 Fax: (504)585–4090. ICEC@mailhost.tcs. tulane.edu. <http://www.people.virginia.edu/~jtd/iccidd/>.

U.S. Fund for UNICEF. 333 East 38th Street NY, NY 10016. webmaster@unicefusa.org. <http://www.unicefusa.org/issues99/sep99/learn.html>.

World Health Organization (WHO). Avenue Appia 20 1211 Geneva 27, Switzerland. (+00–41–22)791–21–11. Fax: (+00–41–22)791–311. info@who.int. <http://www.who.int/inf-fs/en/fact121.html>.

OTHER

HealthWorld Online. <http://www.healthy.net>.

Kathy Stolley

Teresa G. Odle