Selenium Interactions

Iodine is the raw material for thyroid hormones T4 and T3, but selenium is required to build the deiodinase enzymes that convert inactive T4 into active T3 in peripheral tissues. Selenium also powers glutathione peroxidase, which protects thyroid follicular cells from the oxidative damage of iodine handling.

NAC supplies cysteine for glutathione synthesis while selenium is the obligate cofactor in glutathione peroxidase enzymes, which use glutathione to neutralize peroxides. Without adequate selenium, the glutathione that NAC helps produce cannot be fully utilized in peroxide detoxification.

Vitamin E and selenium work as complementary antioxidants. Selenium is the cofactor for glutathione peroxidase, which clears lipid peroxides, sparing vitamin E. Vitamin E in turn prevents lipid peroxidation, reducing demand on the selenium-dependent enzyme.