Thyroid goitrogenic foods
Goitrogens are substances that disrupt the production of thyroid hormones by interfering with iodine uptake in the thyroid gland. This triggers the pituitary to release thyroid-stimulating hormone (TSH), which then promotes the growth of thyroid tissue, eventually leading to goiter. Goiter will eventually adversely affect thyroid function.
Goiter will eventually adversely affect thyroid function.
Foods which have been demonstrated to have goitrogenic effects include Soy, Cassava (when crushed and not detoxified by soaking,) vegetables in the genus Brassica such as broccoli and cabbage), and other cruciferous vegetables.
List of Goitrogenic Foods
- Soy foods including tofu, edamame, soy milk, soy beans
- Cruciferous vegetables unless cooked well, i.e. kale, cabbage, cauliflower, broccoli, spinach, etc.
- Certain fruits such as pears, peaches and strawberries, and some vegetables such as sweet potato
- Some nuts and seeds such as pine nuts, peanuts, millet
Goitrogen intake seems to be problematic only for those who are deficient in iodine according to recent studies, so maintaining an adequate, but not excessive, intake of iodine is crucial. Also, cooking goitrogens thoroughly seems to inactivate the goitrogenic offenders. In addition, the balance of iodine to selenium is crucial. Adequate selenium needs to be present with adequate iodine for the thyroid to function optimally.
Other Offending Food Frequently Classified with Goitrogens
Gluten containing foods such as beer, wheat, pasta, noodles, bread are often avoided in hypothyroidism since 80% of hypothyroid cases are autoimmune based and gluten intolerance is an autoimmune disorder characteristic of celiac disease. If a patient has one auto- immune disorder the chances of another coexisting disorder such as gluten intolerance has been shown to be high.
People with hypothyroidism have plenty of options for a healthy diet. They can eat eggs, meats, fish, most fruit and vegetables, gluten-free grains and seeds, dairy and non-caffeinated beverages.
Goitrins and thiocyanates are released from certain plant-based foods when they are sliced or chewed in their raw state. Flavonoids in foods can be transformed into goitrogens and should be considered in the overall diet.
Sources of Flavonoids
Berries, red wine, soy, and teas are strong sources of flavonoids. Flavonoids are converted into goitrogenic substances by gut bacteria.
A Word About Soy
Soy may not affect the thyroid gland of those patients with adequate iodine intake but they may affect the absorption of the medication and for regular consumers of soy a dosage increase in thyroid medication may be in order.
There is also some concern that consuming isoflavones, the active ingredients in soy, may trigger a biotransformation from subclinical to overt hypothyroidism in patients with insufficient or borderline iodine intake. Research regarding this is ongoing and controversial.
A good hypothyroid diet will avoid uncooked goitrogens, limit overconsumption of soy, opt for beverages other than tea, limit an overabundance of flavonoids and will take into account the possibility of gluten intolerance by having a test for celiac disease done to further individualize the diet for optimum thyroid health.