Selenium†

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.6 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 (Figure 1). Low plasma selenium concentrations have been found to be associated with impaired conversion of T4 to T3.7

The thyroid gland is a highly metabolically active tissue in which oxidative processes are indispensable for thyroid hormone synthesis. This is namely because that the thyroid naturally produces large amounts of hydrogen peroxide (H2O2). Hydrogen peroxide is a necessary substrate for thyroid peroxidase (TPO), an enzyme expressed mainly in the thyroid, which plays a major role in thyroid hormone synthesis (Figure 1).

Under healthy physiological conditions, a balance between the generation and detoxification of free radicals is maintained.