Thyroid Foods to Avoid

A delicate balance of thyroid hormones, most importantly thyroxine and triidothyronine, are essential for many of your bodily functions, including metabolism. Too little hormone may cause pervasive fatigue, drowsiness, weight gain and constipation. This underactivity of the thyroid gland is known as hypothyroidism. The disease affects both sexes and all ages, but the risk of developing hypothyroidism increases with age, most commonly in women over 50. Some fruits and vegetables rich in phytochemicals cyanide glucosides and thioglucosides have been found to cause hypothyroidism.

Soy

Soy or soybean has been used for at least 5,000 years as a source of dietary protein. Soy is generally considered safe for a wide range of intakes, although there have been persistent concerns about its effects on the thyroid. Some studies have found high intakes of soy isoflavones, estrogen-like substances, may inhibit thyroid function via inhibition of action of thyroid peroxidase, an enzyme essential for the production and transportation of thyroid hormones, Washington State University says.

Cabbage

Preliminary studies have found an association between high intakes of cruciferous vegetables, such as cabbage, and an increased incidence of goiters, an enlargement of the thyroid gland. Cabbage contains natural goitrogens glucosinolates, which appear to inhibit iodine uptake by the thyroid, resulting in decreased production of the important hormone thyroxine, according to Lock Haven University.

Brussels Sprouts

Brussels sprouts are also not recommended for patients diagnosed with hypothyroidism. Some studies have found brussels sprouts contain phytochemicals that cause the thyroid to enlarge by naturally suppressing thyroid hormone synthesis.