Selenium Status and Immune Function

A small double-blind, placebo-controlled trial published in the American Journal of Clinical Nutrition (2004; 80:154–162) evaluated how selenium supplementation affects immune markers. Sixty-six adults with low baseline serum selenium were randomized to receive:

  • Placebo

  • 50 mcg/day of selenium

  • 100 mcg/day of selenium

After supplementation, serum selenium levels rose in both selenium groups. Researchers also documented improved cellular immune responses, including:

  • Increased production of interferon-gamma and other cytokines

  • Increased numbers of T-helper cells (a key category of lymphocytes)

  • Enhanced ability to control viral replication

The viral findings are especially interesting in light of earlier research published in FASEB Journal (June 8, 2001), showing that harmless viruses can mutate into more virulent forms when their host is deficient in selenium or vitamin E. Adequate antioxidant status appears to help maintain viral stability and support normal immune defense.