Selenium and Graves’ Disease

Selenium, a trace element present in specific selenoproteins, is essential for thyroid hormone metabolism. Selenium is also an antioxidant with immunosuppressive properties and may help in managing thyroid autoimmune diseases, including Graves’ (GD) hyperthyroidism and Graves’ ophthalmopathy (GO). There were 320 clinical studies related to selenium and thyroid published in English and French between January 1, 2000, and June 1, 2023. Our focus was to identify studies reporting levels of serum selenium in patients with GD and studies that assessed the effect of selenium supplementation on outcomes of GD hyperthyroidism and GO. We also reviewed 20 systematic reviews and meta-analyses of randomized controlled trials that reported selenium levels in GD and the effects of supplementation on GD and GO outcomes. Our review showed that patients with GD had serum selenium levels lower than those of various control patients. In the short-term, a selenium supplement to antithyroid drugs showed benefit for GD hyperthyroidism in most studies, but long-term benefits and positive effects on remission rate were unclear. Some studies did not show benefit. The benefits may depend on baseline selenium deficiency. Two randomized controlled trials showed positive effects of supplementation for mild GO; however, studies about moderate and severe GO are still needed. There is evidence for benefit with short-term selenium supplementation for GD hyperthyroidism, but controlled studies are needed to assess long-term benefits, and benefits in selenium-sufficient areas.