Abstract
Selenium (Se) is an essential trace element of fundamental importance for human health. Se is incorporated into selenoproteins (SPs) which are endowed with pleiotropic effects including antioxidant and anti-inflammatory effects and active production of thyroid hormones. It has also been suggested that Se plays a crucial role in the pathogenesis of various human diseases. The therapeutic effects of supplementation with Se have already been described in various thyroid diseases. However, there are still conflicting results regarding the optimal dose of Se to administer and the duration of treatment, efficacy, and safety. The highly beneficial effects of supplementation with Se have been observed in subjects with thyroid disease in the hyperthyroid phase. In line with these observations, clinical studies have shown that in patients with Basedow's disease (BD) and autoimmune thyroiditis (AT), treatment with a combination of antithyroid drugs and Se restores the euthyroid state faster than administration of antithyroid drugs alone. However, the efficacy of this therapeutic approach remains to be better evaluated.