A landmark study conducted in Japan explored the antitumor potential of common edible mushrooms, such as Shiitake (Lentinus edodes) and Maitake (Grifola frondosa), when administered orally to tumor-bearing mice. By supplementing standard feed with 10–30% powdered fruiting bodies, researchers observed significant reductions in tumor growth—up to 58.3% with Shiitake and 43.3% with Maitake in mice with Sarcoma-180. This demonstrates that the mushrooms’ effects are not limited to injectable extracts but can be effective through daily diet.
Notably, the study found that timing and composition of mushroom feed played key roles. When administered simultaneously with tumor implantation, suppression reached up to 72.4%. Further experiments confirmed that both polysaccharides (like β-glucans) and lipids present in the mushrooms contributed to the observed tumor inhibition. Once both components were removed, the suppressive effect disappeared entirely—highlighting the synergistic nature of whole mushroom compounds in supporting immune responses and slowing tumor development.
Beyond Shiitake and Maitake, other mushrooms such as Tremella fuciformis, Enokitake, and Hiratake also demonstrated antitumor effects—some reaching over 80% tumor growth inhibition. This study supports the idea that regular consumption of functional mushrooms may help activate immune cells like macrophages and T-cells, potentially playing a role in natural cancer prevention strategies.