Goitrogens are substances that suppress the function of the thyroid gland by interfering with iodine uptake.

Certain foods have been identified as goitrogenic. These foods include:

• Soybeans, Pine nuts, Peanuts, Millet, Strawberries, Peaches, Spinach, Bamboo shoots, Radishes, Horseradish, Vegetables in the genus Brassica including: Bok choy, Broccoli, Broccolini, Brussels sprouts, Cabbage, Canola, Cauliflower, Chinese cabbage, Collard greens, Kale, Kohlrabi, Mustard greens, Rapini, Rutabagas, Tatsoi, and Turnips

Some foods and drinks have an opposite effect on the thyroid gland--that is, they stimulate thyroid function rather than suppressing it; examples being avocado, coconut, and saturated fat.

References

Takizawa T, Imai T, Ueda M, Onodera H, Hirose M (2006). "Comparison of enhancing effects of different goitrogen treatments in combination with beta-estradiol-3-benzoate for establishing a rat two-stage thyroid carcinogenesis model to detect modifying effects of estrogenic compounds". Cancer Sci. 97 (1): 25–31. doi:10.1111/j.1349-7006.2005.00132.x. PMID 16367917.