2. Soy
Phytoestrogens found in soy prevent the thyroid from using iodine (4).
This in turn means that important thyroid hormones aren’t secreted, which can lead to hypothyroidism.
Soy isoflavones may also increase the incidence of autoimmune thyroid disease by inducing the production of P40, a strong autoimmunogen (5).
If you’re concerned about your thyroid health make an effort to avoid unfermented soy products, since they contain anti-nutrients that can cause digestive stress and malnutrition.