Supplements

Iodine

Iodine is needed only in trace amounts to help metabolize excess fat. It is important for physical and mental development.

Children whose diets are low in iodine usually display little intellectual motivation and will likely develop learning disabilities. Testing the thyroid isn't always an accurate gauge of the potential risk.

A low-iodine diet may lead to a decrease in IQ and a loss of eye coordination. Because the mineral has been studied only as a preventive, scientists don't know if iodine supplements can reverse the learning disabilities or improve scores on intelligence tests.

Experimentally, high doses of iodine have been used to treat polio, viral disease, and some disorders of the central nervous system.

Fibrocystic breasts, endometriosis, and uterine fibroids are a few of the specific women's health conditions that iodine supplementation may relieve. The requisite high dosage of molecular iodine used in these studies can be toxic, however, and must be taken only under medical supervision. Iodine helps to convert estradiol into estriol, a safer, less bioactive form of estrogen.

Iodine is needed for a healthy thyroid gland and for the prevention of goiter. Replacing the missing iodine won't heal an underactive thyroid gland; at best it may renew hormone production, but only if an actual deficiency exists.

Deficiency: Iodine deficiency has been linked to breast cancer and is associated with fatigue, neonatal hypothyroidism, and weight gain.

Depleting Agents: Food processing, nutrient-poor soil

Sources: Foods that are high in iodine include dairy products (from cattle fed iodine-supplemented feed and salt licks), iodized salt, seafood, saltwater fish, and kelp. It can also be found in asparagus, dulse, garlic, lima beans, mushrooms, sea salt, sesame seeds, soybeans, spinach summer squash, Swiss chard, and turnip greens.

Precautions: Excessive iodine intake (sometimes as little as 750 mcg daily) may inhibit the secretion of thyroid hormone and can produce a metallic taste and sores in the mouth, swollen salivary glands, diarrhea, and vomiting.

Some foods block the uptake of iodine into the thyroid gland when eaten raw in large amounts. These include Brussels sprouts, cabbage, cauliflower, kale, peaches, pears, spinach, and turnips. If you have an underactive thyroid, you should limit your consumption of these foods.

Dosage Ranges and Duration of Administration: The RDAs for iodine are as follows:

Infants:

• 0 to 6 months: 40 mcg
• 6 to 12 months: 50 mcg

Children:

• 1 to 3 years: 70 mcg
• 4 to 6 years: 90 mcg
• 7 to 10 years: 120 mcg

Adolescents and Adults:

• 11+ years: 150 mcg
• Pregnant females: 175 mcg
• Lactating females: 200 mcg

The measures above are typically surpassed in dietary intake in the U.S. and other developed countries, making supplementation unnecessary.

At the very most, a daily multimineral supplement that contains 100 mcg of iodine will cover most people's needs. Larger doses, should be supervised by a physician.

Natural kelp is a good source of supplemental iodine.