Effects of selenium toxicity and deficiency on humans

Thesis Abstract

Abstract
Selenium is an essential trace element for human health, playing a crucial role in antioxidant defense systems and thyroid hormone metabolism. Both selenium deficiency and toxicity can have significant impacts on human health. Selenium deficiency is a global issue, with certain regions being particularly at risk due to low selenium levels in the soil. This deficiency can lead to conditions such as Keshan disease and Kashin-Beck disease, which affect the heart and joints, respectively. In contrast, selenium toxicity can occur from excessive supplementation or environmental exposure, leading to selenosis, which manifests with symptoms such as hair loss, gastrointestinal disturbances, and neurological issues. The effects of selenium deficiency on humans are well-documented and include increased risk of cardiovascular disease, impaired immune function, and cognitive decline. Selenium deficiency has also been linked to male infertility and certain types of cancer. On the other hand, selenium toxicity is less common but can result in serious health consequences. Acute selenium toxicity can cause symptoms such as garlic breath odor, nausea, and neurological abnormalities, while chronic exposure may lead to more severe effects on the liver, kidneys, and nervous system. Understanding the mechanisms underlying selenium toxicity and deficiency is crucial for developing strategies to prevent and treat these conditions. Selenium acts as a double-edged sword, with optimal levels being essential for health, but both excess and deficiency posing risks. The bioavailability of selenium in the diet is influenced by various factors, including soil content, food sources, and genetic variations in selenoproteins. Selenium supplementation is recommended in regions where deficiency is prevalent, but care must be taken to avoid excessive intake. Research on selenium continues to uncover new insights into its role in human health and disease. Recent studies have explored the potential benefits of selenium in cancer prevention, cardiovascular health, and immune function. However, more research is needed to fully understand the optimal selenium status for different populations and to establish safe intake levels. By considering both the risks and benefits of selenium, healthcare professionals can help individuals achieve a balanced selenium status to promote overall health and well-being.