Controversies about selenium supplementation

Abstract

Introduction. Selenium (Se) is a trace element found mainly in meat, seafood, nuts and grains. Se is found in selenoproteins such as selenocystein or selenomethionin. A well balanced diet provides enough Se. Many regulatory and metabolic enzymes contain Se as their component, which is why Se supplementation is used in the treatment as well as prevention of multiple disorders. Se may, however, be toxic if overdosed. Aim. The aim of this review is to summarize the data about functions of Se in human body and to discuss its use in treatment and prevention of diseases. Materials and methods. The search was conducted using the PubMed and Google Scholar databases in March and April 2020. The key words used were: ‘selenium’, ‘cardiovascular disease’, ‘selenium supplementation’, ‘Keshan disease’, ‘source of selenium’. A total of 68 articles were analysed. Results. The first cases of chronic Se deficiency cases were documented 85 years ago in China. The patients with cardiomyopathy, extensive fibrosis and degenerative changes in the heart were diagnosed with Keshan disease. Human selenoproteonome consists of at least 25 selenoproteins. Se plays a role in immunity and metabolism via its role in functioning of numerous enzymes: glutathione peroxidase, thioredoxine and methionine sulfoxide reductase, methionine-sulfoxide reductase B1. Se plays a role in glucose homeostasis, Alzheimer’s disease, thyroid disorders, infectious, inflammatory diseases, vascular diseases and fertility. Conclusion. Se deficiency increases the risk of Keshan disease, but there is not enough evidence to recommend its supplementation for prevention of cardiovascular disease. However, Se status is important part of health assessment. Se supplementation should not exceed the dose of 55μg/day.