Goitrogens

Goitrogens are substances that interfere with the production of thyroid hormones by disrupting the thyroid’s uptake of iodine, its hormone synthesis, or release of hormones. This can lead to enlargement of the thyroid gland, or goiter, particularly when iodine intake is insufficient.

Sources of goitrogens include certain plant compounds in cruciferous vegetables such as broccoli, cabbage, kale, cauliflower, and Brussels sprouts, which contain glucosinolates that can be metabolized to thiocyanates that inhibit iodine utilization. Other plant sources include cassava, which contains cyanogenic glycosides that can form goitrogenic compounds when not properly processed or cooked. Some evidence also links goitrogenic effects to certain compounds found in soy and other legumes, especially in the context of low iodine intake. Cooking and processing can reduce goitrogenic activity in many foods.

Clinical significance varies with iodine status. In people with adequate iodine intake, typical dietary amounts of goitrogenic foods are unlikely to cause thyroid dysfunction. In iodine-deficient individuals or those with preexisting thyroid disease, goitrogens may contribute to hypothyroidism or more pronounced goiter, particularly if consumption is high and iodine supply remains limited. Management focuses on ensuring sufficient iodine intake, balanced diet, and, if thyroid dysfunction is present, medical evaluation and appropriate treatment. For most people, moderate consumption of cruciferous vegetables and other goitrogen-containing foods is considered safe and beneficial due to their nutrient content, with goitrogen exposure generally not a major concern when dietary iodine is adequate.