natural treatment for thyroid goiter

I was diagnosed with multinodular thyroid goiter one year ago. I have them on both sides of my thyroid and my thyroid function is fine so far. I have read that some foods mainly soy are goitrogens. I have started avoiding soy products. Can you explain what role a goitrogen plays in nodule formation? Does increasing iodine intake or anything else prevent or reduce goiter size?
My endocrinologist recommended that I take synthroid to "put my thyoid to sleep", thus shrinking the size. After I refused the treatment he wasn't happy with my decision. I am looking for natural way to treat my goiters without any side effects. Tweet