Effects of selenium toxicity and deficiency on humans

Thesis Abstract

Abstract
Selenium is a trace element that is essential for human health, playing a critical role in various physiological processes such as antioxidant defense, thyroid hormone metabolism, and immune function. Both selenium deficiency and toxicity can have significant effects on human health. Selenium deficiency is associated with conditions such as Keshan disease, Kashin-Beck disease, and myxedematous endemic cretinism, which can manifest as cardiomyopathy, osteoarthritis, and cognitive impairment, respectively. In contrast, selenium toxicity can result in selenosis, a condition characterized by hair and nail loss, skin lesions, gastrointestinal disturbances, and neurological abnormalities. The effects of selenium toxicity and deficiency on humans are complex and multifaceted. Selenium deficiency can impair the body's antioxidant defense mechanisms, leading to increased susceptibility to oxidative stress and potentially contributing to the development of chronic diseases such as cancer, cardiovascular disease, and neurodegenerative disorders. Additionally, selenium deficiency has been linked to compromised immune function, thyroid dysfunction, and male infertility. On the other hand, selenium toxicity can occur when the intake of selenium surpasses the body's capacity to metabolize and excrete it. Chronic exposure to high levels of selenium can lead to the accumulation of selenium in tissues, resulting in oxidative damage and disruption of cellular functions. Selenium toxicity has been associated with adverse effects on the skin, hair, nails, nervous system, and gastrointestinal tract. Furthermore, excessive selenium intake has been implicated in the development of diabetes, cardiovascular disease, and other health conditions. The impact of selenium toxicity and deficiency on human health underscores the importance of maintaining optimal selenium status through a balanced diet and, if necessary, supplementation. Strategies to prevent selenium deficiency include consuming selenium-rich foods such as Brazil nuts, seafood, eggs, and organ meats. However, care must be taken to avoid excessive selenium intake, as the tolerable upper intake level for selenium has been established to prevent toxicity. In conclusion, selenium is a vital micronutrient with diverse roles in human physiology, and both deficiency and toxicity can have profound effects on health. Understanding the mechanisms underlying the effects of selenium imbalance is crucial for developing strategies to optimize selenium status and mitigate the risks associated with inadequate or excessive selenium intake.