Soy, peanuts and cruciferous vegetables.
Goitrogenic substances, which cause enlargement of the thyroid gland, have been found in legumes such as soybean and groundnut. They have been reported to inhibit the synthesis and secretion of the thyroid hormones. Since thyroid hormones play an important part in the control of body metabolism their deficiency results in reduced growth and reproductive performance (Olomu, 1995). Goitrogenic effect have been effectively counteracted by iodine supplementation rather heat treatment (Liener, 1975).