There are some foods that are considered "goitrogenic." They can promote goiters and
result in hypothyroidism by reducing the amount of iodine in the body that is available to
help synthesize T4 and T3. But they seem to only present a problem when eaten raw and
in large quantities. Some of the more common goitrogens are raw cruciferous vegetables
such as broccoli, cauliflower, brussels sprouts and cabbage, and kale, turnips, soy and others.
Soy products can be a problem but only if eaten in excess. I have read that 1 to 2 servings of
soy a day should not cause thyroid problems.