SELENIUM AND AUTOIMMUNE THYROIDITIS

Selenium (Se) is an essential trace element of pivotal importance to human health. Se is incorporated into selenoproteins (SePs) which have pleiotropic effects, including antioxidant and anti-inflammatory effects, and in the production of active thyroid hormone. These findings may explain the relationship between Se deficiency and pathogenesis of various human diseases including thyroid disorder. In line with these observations, the therapeutic effectiveness of Se supplementation has already been reported in patients with various thyroid diseases. However, there are still controversial data about the optimal dose of Se to be administered, as well as the duration and efficacy of treatment and safety of this trace element. It is currently recommended to administer Se supplements following the assessment of any deficiency status of this element and, after that, its association with chronic autoimmune thyroid disease has been proven. Consistent with these observations, several clinical studies have highlighted the fact that Se supplementation in patients with chronic autoimmune thyroid disease was associated with a reduction of thyroid autoantibodies, and with an improvement of the thyroid-associated ophthalmopathy. The beneficial effects of Se supplementation have been reported in subjects with thyroid disease during the hyperthyroid phase. The restoration of euthyroidism is a major goal in the management of thyrotoxicosis of Graves’ disease. In line with these observations, clinical studies have shown that, in patients with Graves' disease and autoimmune thyroiditis, treatment with a combination of antithyroid drugs and Se restore the euthyroid status faster than the administration of anti-thyroid drugs alone. The review shows that the treatment of an autoimmune thyroid disease with Se may bring about beneficial effects.