Cruciferous vegetables are a nutrient rich food with cancer preventing abilities that most experts agree should be a daily part of one's diet. However, reports vary as to the impact these vegetables have on the thyroid.
The thyroid is a gland found in a person's neck. It plays an essential role in energy production, the metabolism, hormone tolerance and protein production. Thyroid problems generally persist when the gland is either overactive (hyperthyroidism) or underactive (hypothyroidism).
Cruciferous vegetables alone do not cause thyroid problems or lead to thyroid cancer in people without thyroid disease. Though unsubstantiated reports may suggest otherwise, there is no scientific evidence to support this claim. There is evidence to suggest that cruciferous vegetables may have adverse effects on people already suffering from thyroid dysfunction or iodine deficiency.
Cruciferous vegetables such as broccoli, cauliflower and cabbage contain goitrogens which, when consumed, may result in the condition known as goiter or an enlarged thyroid gland. When this condition persists, goitrogens block the absorption of iodine, which is essential to healthy thyroid function. If an individual takes medication to treat a thyroid disease such as goiter, eating cruciferous vegetables may also block the body's ability to absorb these medicines or supplements.
One study of a particularly high rate of thyroid cancer in New Caledonia concluded that there was a relationship between consuming high levels of cruciferous vegetables and the development of thyroid cancer in people with low iodine intake or iodine deficiency.
However, cruciferous vegetables may not be completely off limits to people with thyroid problems. Cooking cruciferous vegetables breaks down many of the enzymes that may contribute to thyroid problems and small amounts of cruciferous vegetables have not been proven to worsen the effects of thyroid disease.
Patients suffering from hyperthyroidism, hypothyroidism, goiter, thyroid cancer or other thyroid problems should always consult a doctor before drastically altering their diet or taking supplements to treat their condition.