Effects of orally administered yeast‐derived beta‐glucans: A review

Yeast‐derived beta‐glucans ( Y ‐ BG ) are considered immunomodulatory compounds suggested to enhance the defense against infections and exert anticarcinogenic effects. Specific preparations have received G enerally R ecognized as S afe status and acceptance as novel food ingredients by E uropean F ood S afety A uthority. In human trials, orally administered Y ‐ BG significantly reduced the incidence of upper respiratory tract infections in individuals susceptible to upper respiratory tract infections, whereas significant differences were not seen in healthy individuals. Increased salivary I g A in healthy individuals, increased IL ‐10 levels in obese subjects, beneficial changes in immunological parameters in allergic patients, and activated monocytes in cancer patients have been reported following Y ‐ BG intake. The studies were conducted with different doses (7.5–1500 mg/day), using different preparations that vary in their primary structure, molecular weight, and solubility. In animal models, oral Y ‐ BG have reduced the incidence of bacterial infections and levels of stress‐induced cytokines and enhanced antineoplastic effects of cytotoxic agents. Protective effects toward drug intoxication and ischemia/reperfusion injury have also been reported. In conclusion, additional studies following good clinical practice principles are needed in which well‐defined Y ‐ BG preparations are used and immune markers and disease endpoints are assessed. Since optimal dosing may depend on preparation characteristics, dose‐response curves might be assessed to find the optimal dose for a specific preparation.