What role does Selen play in allergy?

Selenium is an essential trace element that supports antioxidant defense and immune regulation via selenoproteins like glutathione peroxidases. In allergy research, observational studies suggest low selenium status may be linked to increased inflammation and allergic conditions such as asthma. However, the evidence is weak and inconsistent. Randomized controlled trials (RCTs) do not demonstrate a clear benefit of selenium supplementation for allergy prevention or treatment. Furthermore, large trials (SELECT, Cochrane) indicate increased risks of diabetes and mortality with high-dose selenium. The general RDA is 55–70 µg/day; the tolerable upper intake level is 300–400 µg/day. A genetic variant in GPX1 (rs1050450) may slightly increase selenium needs, but this does not justify supplementation without medical advice. For allergy sufferers, adequate selenium from food sources (e.g., Brazil nuts, fish, eggs) is reasonable, but high-dose supplements are not recommended. The overall evidence is mixed (mechanistic/observational).