There is a growing body of evidence that diet can affect thyroid function. Eating certain foods may actually alter the function of your thyroid, although the jury is out on how significant the effects of those foods are. If you have impaired thyroid function, such as hypothyroidism or Hashimoto's thyroiditis, certain foods--called goitrogens--are more likely to have an impact on your thyroid health than they will with people who have a healthy thyroid.
Goitrogenic Foods
Many foods that are part of your everyday diet are considered to be goitrogens. According to MedicineNet, a goitrogenic food is one that "can affect thyroid function by inhibiting the synthesis of thyroid hormones." This inhibition of thyroid hormones can lead to thyroid enlargement and sluggish thyroid function.
Marcelle Pick, an OB/GYN nurse practitioner at Women to Women lists several goitrogenic foods that potentially affect thyroid function, including gluten, soy, and cruciferous vegetables such as cabbage, Brussels sprouts and mustard. Other foods that are potentially goitrogenic include pine nuts, spinach and strawberries.
Eating Foods that Contain Goitrogens
According to Pick, eating goitrogen-containing foods in moderation most likely won't cause hypothyroid disease, although it may have an affect on the absorption of thyroid medications like synthroid and Armour thyroid. Eating large amounts of goitrogenic foods such as soy, however, may negatively affect thyroid function, according to noted thyroid expert and author Mary Shomon. Thyroid problems resulting from intake of soy may begin in infancy with the use soy formula; and Shomon says that research shows that no amount of soy is safe for infants, and only 30 mg of soy isoflavones per day are considered safe for adults.
Minimizing the Effects of Goitrogens
The goitrogenic effects of foods can be minimized using certain preparation and serving techniques. According to Pick, cooking and fermenting foods will minimize the impact of goitrogens on thyroid function. So will pairing goitrogenic foods with foods that are rich in iodine or taking iodine supplements. This means that fermented soy foods such as miso may confer all of the reputed the health benefits of soy while minimizing any negative impact soy could have on your thyroid.
The Benefits of Iodine
Iodine plays an important role in maintaining thyroid function. Not only can it block the effects from eating goitrogenic foods, but your thyroid needs iodine in order to produce its two main hormones, thyroxine and triodothyronine. If there is one nutrient that you need in your diet to maintain your thyroid health, it is iodine. So essential is iodine, that many table salts are iodized in order to supply the body with this nutrient. Other foods that contain iodine include yogurt, eggs and sea vegetables.
The Bottom Line
The foods you eat may, indeed, have an effect on your thyroid function, particularly if you are taking thyroid medications. In most cases, if you are eating goitrogenic foods in moderate amounts, the effects on your thyroid will most likely be negligible; however, if you are eating large amounts of goitrogenic foods, you may want to have a little iodine to counteract any impact those foods will have on your thyroid. If in doubt about any specific foods, contact your health care provider or endocrinologist for more information.
