Selenium supplements: is it advisable to use them in treatment of pathology of the thyroid gland?

Abstract

The article is a review of the literature in Scopus, Web of Science, MedLine and The Cochrane Library and is devoted to the analysis of the evidence base of the use of selenium supplements for the treatment of thyroid pathology. Despite the variety of thyroid pathology: changes in size and structure, hypo- and hyperfunction, autoimmune, oncopathology, there are not so many drugs used in its medical treatment. Drugs that are justified for various thyroid pathologies include iodine, levothyroxine and, to some extent, triiodothyronine, thyrostatics (methimazole, carbimazole, propylthiouracil), radioactive iodine and glucocorticoids, such as beta-blockers. Acute thyroiditis requires the appointment of antibacterial therapy, and oncopathology — specific chemotherapeutic agents, the effectiveness of which, unfortunately, is not high, and the frequency of appointment is significant. Along with these drugs, selenium drugs have become unprecedented in the last decade in thyroid pathology as a component of possible pathogenetic therapy. These drugs are prescribed to patients with diametrically opposed functional state of the thyroid gland, autoimmune patho­logy, nodules. It appears that thyroid carcinogenesis remains the only pathology where the use of selenium drugs is not recommen­ded, although there are studies that indicate a link between thyroid cancer and selenium deficiency. The results of clinical studies and meta-analyzes are provided through the prism of a survey of Italian and European endocrinologists on the appointment of selenium drugs for the treatment of relevant thyroid pathology. The lack of evidence base for the use of selenium in most types of pathology of the thyroid gland: autoimmune thyroiditis, overt and subclini­cal hypothyroidism, Graves’ disease. According to most studies, the supplementation of selenium to therapy increases its plasma level, affects the activity of selenoproteins and level of antithyroid antibodies, but in no way affects the main clinical parameters such as thyroid hormones, levothyroxine dose, clinical symptoms. In ge­neral, the use of selenium in thyroid pathology cannot be considered appropriate, except for a mild form of Graves’ orbitopathy. Signi­ficant differences in the data of clinical trials and recommendations of thyroid societies with a real frequency of selenium administration by practitioner for the treatment and prevention of thyroid pathology are indicated.