Project Abstract

Abstract
Selenium is an essential trace element that plays a critical role in human health. Both selenium toxicity and deficiency can have significant impacts on human well-being. This research project aims to investigate the effects of selenium toxicity and deficiency on humans, focusing on various physiological aspects and potential health outcomes. Selenium toxicity can occur when the intake of selenium exceeds the tolerable upper intake level. This can lead to selenosis, characterized by symptoms such as hair loss, nail brittleness, gastrointestinal disturbances, and neurological abnormalities. Chronic selenium toxicity has been associated with more severe effects, including skin lesions, respiratory distress, and even death in extreme cases. Understanding the mechanisms underlying selenium toxicity is crucial for developing strategies to prevent and manage this condition. Conversely, selenium deficiency is a widespread issue in many parts of the world, particularly in regions where the soil is low in selenium content. Inadequate selenium intake can result in various health problems, including weakened immune function, increased risk of cardiovascular diseases, and impaired thyroid function. Selenium deficiency has also been linked to cognitive decline and certain types of cancer. Addressing selenium deficiency is essential for promoting overall health and well-being in populations at risk. This research project will explore the intricate relationship between selenium levels and human health outcomes. By analyzing the physiological effects of both selenium toxicity and deficiency, this study aims to provide valuable insights into the mechanisms through which selenium influences various biological processes. Furthermore, the project will investigate potential interventions to mitigate the adverse effects of selenium toxicity and deficiency, such as targeted supplementation strategies and dietary modifications. Overall, this research project seeks to enhance our understanding of the complex role of selenium in human health and disease. By elucidating the effects of selenium toxicity and deficiency on different physiological systems, this study aims to contribute to the development of evidence-based recommendations for selenium intake levels. Ultimately, the findings from this research project may have implications for public health policies and interventions aimed at improving selenium status and reducing the burden of selenium-related health issues in human populations.

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.