The Role of Selenium in Thyroid Autoimmunity: A Review

Autoimmune thyroid diseases, including Graves’ disease and Hashimoto’s thyroiditis, are the most common autoimmune conditions in humans. There is significant morbidity associated with thyroid autoimmunity, and typically ongoing management is required to control disease presentation and reduce sequelae. Thyroid tissues contain the highest concentration of selenium in the body, owing to selenium’s crucial role in glutathione peroxidases, thioredoxin reductases, and iodothryonine deiodinases. Selenium deficiency is associated with sub-optimal thyroid function, and has been shown to be a risk factor for both Hashimoto’s thyroiditis and Graves’ disease. As a therapeutic intervention, selenium has been shown in a number of studies to reduce thyroid antibodies, although there remains limited information regarding its impact on clinical outcomes. In Graves’ disease, and specifically in Graves’ ophthalmopathy, selenium appears to play a beneficial role in altering disease progression and improving ophthalmic symptoms. The various functions of selenium in thyroid autoimmunity are reviewed.