Selenium is a trace mineral essential for life, primarily functioning as a key component of selenoproteins, which are powerful antioxidant enzymes like glutathione peroxidase that protect cells from oxidative damage. It is vital for thyroid health, as selenoproteins are required to activate thyroid hormones (converting T4 to T3), making it crucial for regulating metabolism, energy and growth. Selenium deficiency, while geographically dependent, can lead to serious health issues including Keshan disease (a cardiomyopathy), a weakened immune system, cognitive decline, and thyroid dysfunction that mimics hypothyroidism. Food sources like Brazil nuts, seafood, organ meats, and eggs provide selenium, but the content varies depending on…