Iodine is an essential trace mineral found in various forms in nature and is necessary for human growth and development. Dietary sources of iodine include seafood, seaweeds including wakame and nori, navy beans, potatoes, and iodized salt. Approximately 15 to 20 mg of iodine is concentrated in the thyroid gland in a healthy human body. Iodine is necessary for the synthesis of thyroid hormones, as it is one of the most important components of the hormones thyroxine (T4) and tri-iodothyronine (T3). T3 is the most active thyroid hormone and binds to receptors in the liver and brain to regulate gene expression. In addition to supporting thyroid hormone production, research shows iodine acts as an antioxidant, supporting a healthy thyroid gland and protecting a variety of tissues, including mammary tissue, the eyes and gastrointestinal lining. In other tissues, such as the mammary glands, the protective role of iodine is connected to its antioxidant function. Iodide can act as an electron donor in the presence of hydrogen peroxide and peroxidase, thereby decreasing damage by free oxygen radicals. In research studies, serum concentrations of iodine as low as 15 micromolar have demonstrated comparable antioxidant activity to vitamin C.
Selenium is a trace mineral required to produce several important compounds, including enzymes involved in antioxidant mechanisms and thyroid hormone metabolism. Selenium intake depends largely on soil conditions in the region where food is grown or raised. Food sources of selenium include Brazil nuts, eggs, peas, poultry and meats. SelenoExcell® is a bioavailable, organic selenium supplement that is closest to forms found in nature. Under-functioning of the thyroid has been found to be common in regions where selenium deficiency rates are high. Selenium is crucial in supporting thyroid health, as it is a required cofactor for three key enzymes involved in the production of thyroid hormones, the iodothyronine deiodinases. Iodothyronine deiodinases catalyze the release of iodine from T4 to T3, allowing for increased production of the more metabolically active thyroid hormone T3. Low plasma selenium concentrations have been found to be associated with impaired conversion of T4 to T3.