Selenium and thyroid function

Abstract

Selenium is an essential trace element embedded in several proteins. Most of the known selenoproteins are found in the thyroid gland and this is the organ with the highest amount of selenium per gram of tissue. Selenium levels in the body depend on the characteristics of the population and its diet, geographic area, and soil composition. In the thyroid, selenium is required for protection from oxidative damage and for the metabolism of thyroid hormones. The literature suggests that selenium intake is associated with autoimmune thyroid disorders and selenium supplementation in those patients is associated with a reduction in antithyroid antibody levels, improved thyroid ultrasound features, and improved quality of life. Selenium supplementation in Graves’ ophthalmopathy is associated with an improved quality of life, less eye involvement, and delayed orbitopathy progression. Supplementation with the organic form is more effective, and benefits in immunological mechanisms have been observed in patients with autoimmune thyroiditis.