Evidence Level
Moderate
Yeast beta-glucans have a well-characterized mechanism of action through Dectin-1 and CR3 receptor binding on innate immune cells. Auinger et al. (2013) conducted a rigorous double-blind RCT showing significant reductions in cold episodes and sick days. The concept of "trained innate immunity" — where beta-glucan exposure epigenetically programs monocytes and macrophages for enhanced future responses — was described by Netea et al. (2011) and has transformed understanding of innate immune memory. Wellmune, the branded yeast beta-glucan ingredient, has been tested in over 10 clinical studies across different populations including marathon runners, stressed adults, and children, consistently showing immune benefits.