Cadmium appears to be the largest single contributor to autoimmune thyroid disease. It is a very powerful and toxic metal which seems to be placed at the very center of the thyroid story. I think you'll find this file very interesting.
Not only does cadmium appear to play a very pivotal role in thyroid disease, it is a very unique mineral. It is extremely toxic and has toxic biological effects at concentrations smaller than almost any commonly found mineral.
Despite this great toxicity, there is some evidence that cadmium is an essential nutrient with biological function. We will be exploring this dichotomy of cadmium.
One of the greatest effects of cadmium is that it depletes selenium in the body because selenium is essential for cadmium removal. Selenium atoms combine with cadmium atoms and are escorted out of the body via the bile system. When selenium is depleted by cadmium, there is less selenium to form the deiodinase enzymes which convert T4 to T3, resulting in low T3 and hypothyroidism. Also there is less selenium to form glutathione peroxidase, one of the body's prime antioxidants. This results in greater levels of reactive oxygen species and hydrogen peroxide, which lead to an increased production of thyroid hormone and damage to the thyroid gland.