Background: The prevention of influenza virus infection is a critical public health challenge.Thus new, safe, and effective strategies are needed to reduce the risk of infection. Maitake mushrooms (Grifola frondosa) are popular in Asia for their flavor and immune-stimulating properties. In this study, we examined whether the dietary consumption of Maitake was effective in boosting the potency of influenza virus vaccination.
Methods: We set up a double-blind, placebo-controlled clinical trial (n=50 subjects for Maitake consumption; n=50 for placebo) and analyzed hemagglutination inhibition (HI) antibody titers in response to trivalent influenza vaccine (type A H1N1, H3N2, and type B BX-51B) for a 12-week period of daily Maitake intake (6.825g), beginning 4 weeks before and continuing 8 weeks after vaccination. We also evaluated the efficacy of Maitake for suppression of common cold symptoms by questionnaire.
Results: We found that continuous Maitake intake raised HI titers against influenza type A virus H1N1 and type B virus, and significantly increased the seroconversion rate for older adults (>60 years of age). Additionally, severe cold symptoms including rhinorrhea and headache were significantly improved by Maitake intake.
Conclusion: In this clinical trial, we demonstrated that Maitake intake enhanced antibody production in response to influenza vaccination while simultaneously suppressing multiple common cold symptoms. The current results suggest that Maitake may activate both innate and adaptive immune responses for the prevention of virus infection. In conclusion, we expect that Maitake intake potentiates host defense systems and has a protective effect against influenza virus and other pathogenic viruses and bacteria.