Certain foods contain goitrogens. Foods with goitrogens are “supposed” to slow the thyroid down and “possibly” cause a goiter. Soy is one of the foods that contain goitrogens. The potentially goitrogenic substances in soy are flavanoids.
It is my understanding that one must be at the same time iodine deficient for the soy to affect thyroid function. One would also have to eat impossibly large volumes of goitrogenic containing foods (it would be a mainstay of a diet) for such a food to have an effect.
The problem of soy was first discovered with babies who drank soy milk and because they had no source of iodine their thyroid function was affected. The problem was solved by putting iodine into their formula.
A doctor brought to my attention some time ago that there were certain studies which were done with individuals taking daily for two weeks two soy bean drinks. When the serum flavanoids were tested the concentrations were 4 to 30-fold lower than the levels required to inhibit the thyroid by 50%.
I would like to know about more studies on this subject. Maybe they will come up with results that prove what I said to the contrary. Check with your doctor to see what he has to say too.
In the meantime I would say a small amount of food with soy along with a normal amount of iodine in your diet you should be ok.
Ellen
