I had been treated for hypothyroidism for ten years and only had minor hypo symptoms. In June I increased my soy product intake and my symptoms became severely worse. My GP increased my Synthroid but I still felt terrible. I went on an elimination diet, but I really thought my vitamins/supplements were the problem. Gradually I started to bring everything back and I began to slowly feel better. I was really confused as to the cause and then I read a similar post about soy products and I realized that the only thing I had not returned to was the soy products. I canít say with certainty that soy aggravated my thyroid problems, it could have been the low Synthroid dosage, but soy sure looks suspicious. Anyway, I have stopped all the soy products and continue to feel better.
I suggest stopping the soy products for two weeks, or a month and see how you feel. That will be tough on a vegetarian, but rice and beans arenít so bad.