Evidence check: Selen in the context of Langlebigkeit

Selenium is an essential trace element that acts as a cofactor for selenoproteins (e.g., glutathione peroxidases) with antioxidant and anti-inflammatory functions. Observational studies suggest that adequate selenium status is associated with lower all-cause mortality and reduced risk of age-related diseases such as cardiovascular disease, certain cancers, and cognitive decline. However, randomized controlled trials (RCTs) have not consistently shown benefits of selenium supplementation in well-nourished populations. High intake (> 400 µg/day) can cause selenosis (hair loss, nail brittleness, gastrointestinal upset). Some evidence even links selenium supplementation to increased diabetes risk in individuals with already high baseline levels. For longevity, maintaining a balanced selenium status through diet (Brazil nuts, fish, eggs) is more evidence-based than indiscriminate supplementation. Consumer tests like MyBody-X can measure blood selenium, but results should be interpreted by a healthcare professional considering overall nutrition and health status. Evidence: human-moderate (observational) / mechanistic. Caveat: No strong RCT evidence for longevity benefit in healthy individuals.