How to take a dietary approach to thyroid disorder

The thyroid, a butterfly-shaped gland that lies over the windpipe (trachea) and just below the Adam's apple (larynx), produces hormones that influence almost every function of the body. These hormones regulate metabolism, physical and mental development, nerve and muscle function and circulation. Thyroid hormones also affect the actions of other hormones; for example, they intensify the action of insulin and the body's response to the adrenal hormones that are instrumental in reacting to stress. Here are some tips on controlling your thyroid disorder with your diet.

Unlike other hormone-producing glands, the thyroid needs a specific nutrient — iodine — to produce its hormones.

• Both too much and too little iodine can cause the thyroid to malfunction, either becoming overactive, causing hyperthyroidism, or underactive, causing hypothyroidism.
• The Recommended Dietary Allowance (RDA) for iodine is 150 micrograms per day for adolescents and adults.
• Pregnant women need 220 micrograms per day, nursing mothers need 290 micrograms.
• The use of iodized salt in the typical North American diet, which provides two to six grams of salt each day, easily supplies more than these recommended amounts of iodine.
• Iodine intake of up to 1,000 micrograms a day has no adverse effects on the thyroid.

Even people on low-salt diets get plenty of iodine from seafood, green leafy vegetables and dairy product.

• ­Certain vegetables, mainly cabbage, broccoli and other cruciferous vegetables, contain substances known as goitrogens, which block the effects of thyroid hormones and may lead to goiter.
• Cooking these foods inactivates the goitrogens; consumption of sufficient iodine also prevents adverse effects.

If you have a thyroid disorder, use small amounts of iodized salt and eat plenty of seafood, dairy products, spinach and other vegetables for iodine.

• Fish, dairy products, eggs, deep yellow or orange fruits and vegetables and dark green vegetables provide vitamin A. The conversion of beta-carotene (provitamin A) to two molecules of vitamin A (retinol) is accelerated by thyroxine. People with hypothyroidism may need a higher intake of beta-carotene to meet vitamin A needs.

• Stay away from caffeine. Caffeine may worsen the jittery feeling in someone with an overactive thyroid. Decaffeinated coffee, tea and pop may refresh without adding to nervousness.

• The nicotine in tobacco also adds to feelings of nervousness.

• Alcohol may aggravate the sleepiness and fatigue in a person with an underactive thyroid gland.

• Some people, usually women who are overly weight-conscious, take thyroid hormones as a diet aid. This can have dangerous results, including drug-induced hyperthyroidism, metabolic abnormalities and irregular heartbeat. Thyroid pills should be taken only under careful medical supervision — never for weight control.

Eat plenty of

• Seafood, dark green leafy vegetables and dairy products for iodine.

Limit

• Alcohol and caffeine, if the thyroid gland is overactive.
• Raw vegetables in the cabbage family, if the thyroid gland is underactive.

Avoid

• Smoking.
• High-dose kelp supplements.