Effects of Active Hexose Correlated Compound on the Seasonal Variations of Immune Competence in Healthy Subjects 

This 2014 study was a 4-week, randomized, double-blind, parallel-group, and placebo-controlled study. It evaluated AHCC intake on immune competence in healthy individuals. The results show a significant increase in NK cell activity, while the placebo group showed a remarkable decline in NK cell activity.  

References:

Matsui, Y., Uhara, J., Satoi, S., Kaibori, M., Yamada, H., Kitade, H., Imamura, A., Takai, S., Kawaguchi, Y., Kwon, A. H., & Kamiyama, Y. (2002). Improved prognosis of postoperative hepatocellular carcinoma patients when treated with functional foods: a prospective cohort study. Journal of hepatology, 37(1), 78–86. https://doi.org/10.1016/s0168-8278(02)00091-0