Foods That Affect the Thyroid

The thyroid, a butterfly-shaped gland in your throat, is one of the major organs that controls your metabolism. How well it functions is largely influenced by heredity. However, your diet also has an influence on your thyroid--either making it work better or impairing its proper functioning. Here, you'll learn about foods that affect the thyroid.

Iodine

In the past, people in certain parts of the United States were deficient in iodine. Since iodine is necessary for the proper functioning of the thyroid, this led to high rates of hypothyroidism, a condition in which the thyroid is sluggish and underactive. To solve this problem, companies that manufacture salt have been adding iodine since the 1920s. Iodine is also sometimes added to bread. Most people today get just enough iodine, and according to information from the Centers for Disease Control, it is rare for most people to get too much iodine from their diet. However, if this does happen, it can make the thyroid overactive, causing hyperthyroidism, which requires medical attention.

Seafood and Kelp

Seafood and kelp are foods that tend to be high in iodine. This is because seawater naturally contains iodine, and many animals and plants who live in the ocean contain high levels of this nutrient. When you eat seafood or Asian dishes that use kelp, you will likely be taking in enough iodine to keep your thyroid healthy. People who use kelp supplements, however, may exceed the upper limit of 300 micrograms per day. Taking in too much seafood or kelp on a regular basis could make your thyroid overproduce thyroid hormones.

Cruciferous Vegetables

Cruciferous vegetables such as broccoli, cabbage, cauliflower and turnips are sometimes referred to as "goitrogenic" foods, meaning they impair the function of the thyroid. In people without thyroid disease, the effect is probably negligible, but people who are diagnosed with hypothyroidism sometimes avoid or limit consumption of these foods. Cooking them, rather than eating these vegetables raw, is thought to lessen the effect on the thyroid.

Strawberries and Peaches

Strawberries and peaches are also thought to be goitrogenic foods. As with cruciferous vegetables, cooking these fruits may help lessen their impact on thyroid function. This is because cooking breaks down the compounds in these fruits that make it harder for the thyroid to make the hormones the body needs.

Soy, Dairy and Supplements

Intake of soy and dairy may also affect the function of the thyroid, particularly in people who have already been diagnosed with thyroid disease. Soy is a goitrogenic food and, in large amounts, may slow down the function of the thyroid. Those who are hypothyroid and are taking thyroid replacement medication also often avoid eating soy within a few hours of taking their pills, because soy can interfere with the absorption of the thyroid hormone. Dairy foods, because they are high in calcium, can also interfere with the absorption of thyroid hormones. Taking supplements containing high doses of calcium or iron within a few hours of taking thyroid replacement pills can also hinder absorption.