Project Abstract

Abstract
Selenium is an essential trace element required for various physiological functions in the human body. Both deficiency and toxicity of selenium can have detrimental effects on human health. This research aims to explore the effects of selenium toxicity and deficiency on humans by reviewing current literature on the topic. Selenium deficiency is associated with various health problems, including Keshan disease, Kashin-Beck disease, and thyroid dysfunction. Keshan disease is a potentially fatal condition characterized by cardiomyopathy, while Kashin-Beck disease affects bone development and growth. Selenium is also crucial for thyroid function, and deficiency can lead to thyroid disorders such as hypothyroidism. On the other hand, selenium toxicity can occur from excessive supplementation or environmental exposure. Acute selenium toxicity can result in symptoms such as gastrointestinal disturbances, hair loss, and neurological issues. Chronic selenium toxicity is rare but can lead to selenosis, a condition characterized by a garlic-like odor in the breath, hair loss, and skin lesions. The mechanisms underlying the effects of selenium toxicity and deficiency involve its role in antioxidant defense, selenoprotein synthesis, and gene expression regulation. Selenium functions as a cofactor for various antioxidant enzymes, such as glutathione peroxidases, which protect cells from oxidative damage. Selenoproteins are involved in thyroid hormone metabolism, immune function, and DNA synthesis. Disruption of these pathways due to selenium imbalance can lead to cellular damage and dysfunction. The impact of selenium toxicity and deficiency on human health underscores the importance of maintaining optimal selenium levels through a balanced diet. Foods rich in selenium include Brazil nuts, seafood, organ meats, and whole grains. However, the selenium content in plant-based foods can vary depending on soil selenium levels, making supplementation necessary in some cases. In conclusion, selenium plays a critical role in human health, and both deficiency and toxicity can have serious consequences. Further research is needed to understand the mechanisms of selenium toxicity and deficiency better and develop strategies for preventing adverse health effects. Public health interventions focusing on selenium monitoring and supplementation may help mitigate the risks associated with selenium imbalance in the population.

Project Overview

INTRODUCTION

1.1.          BACKGROUND INFORMATION

Selenium (Se) is an essential trace element having biological functions of utmost importance for human health. Different from the other (semi) metals, it is incorporated into proteins by a co-translational mechanism as part of the amino acid selenocysteine (SeCys), the 21st amino acid used for protein synthesis in humans, whereas only a few of them have been functionally characterized. Most Se-proteins participate in antioxidant defence and redox state regulation, particularly the families of more specific essential roles, such as iodothyronine deiodinases (DIOs) which are involved in thyroid hormones metabolism, GPx4 which is essential for spermatogenesis, and selenophospathe synthetases 2 (SPS2) participating in Se-protein biosynthesis.

Other Se-proteins may be involved in important biological processes, but their exact mechanism of action is still yet to be fully understood. Despite the scarce knowledge of the precise biochemical functions, a very large number of studies have been carried out in the last two decades showing that insufficient Se levels, and particularly Se-proteins, are associated with several human diseases including cancer, diabetes, cardiovascular and immune system disorders. In most cases, the link lies in the contrast to the oxidative stress that may be booth causing or caused by the disease. In this context, it is important to decipher whether and adequate Se status may contrast the risk factors for health disorders, or Se supplementation may improve the therapy when Se metabolism is altered.

Despite many studies that have suggested a beneficial effect from Se supplementation to general health protection, most of them have remarked that it is limited to general health protection, most of them have remarked that it is limited to the initially inadequate Se status. Conversely, care should be taken when using supplements because excessive Se intake leads to toxic effects, and recent studies have shown that even sub-toxic doses may be negatively impacting, for example by increasing the risk of type 2 diabetes.