Grifola frondosa is a species of mushroom usually referred to as maitake in Japan, where it’s indigenous. The mushroom is one of many recognized medicinal mushrooms in Japan and China, but a majority of Western scientists and doctors believe its health benefits are largely folklore. However, scientific investigation during the last decade in Asia has shown that maitake mushrooms contain many nutrients beneficial for health.
Grifola frondosa has been used in Japan and other Asia countries as a food source and medicine for a few thousand years. It was commonly referred to as the dancing mushroom in earlier times because people danced for joy when they found some in the wild — the mushrooms were known to be strongly medicinal, so they were quite valuable.
RESEARCH: In 2009, a phase I/II human trial, conducted by Memorial Sloan–Kettering Cancer Center, showed Maitake could stimulate the immune systems of breast cancer patients26. Small experiments with human cancer patients, have shown Maitake can stimulate immune system cells, like NK cells27. In vitro research has also shown Maitake can stimulate immune system cells28. An in vivo experiment showed that Maitake could stimulate both the innate immune system and adaptive immune system29.
In vitro research has shown Maitake can induce apoptosis in cancer cell lines (human prostatic cancer cells, Hep 3B cells, SGC-7901 cells, murine skin carcinoma cells) as well as inhibit the growth of various types of cancer cells (canine cancer cells, bladder cancer cells). Small studies with human cancer patients, revealed a portion of the Maitake mushroom, known as the “Maitake D-fraction”, possess anti-cancer activity. In vitro research demonstrated the mushroom has potential anti-metastatic properties30-35. In 1997, the U.S. Food and Drug Administration (FDA) approved an Investigational New Drug Application for a portion of the mushroom.
Research has shown Maitake has a hypoglycemic effect, and may be beneficial for the management of diabetes36,37. The reason Maitake lowers blood sugar is due to the fact the mushroom naturally contains an alpha glucosidase inhibitor38.
Maitake contains antioxidants and may partially inhibit the enzyme cyclooxygenase39. An experiment showed that an extract of Maitake inhibited angiogenesis via inhibition of the vascular endothelial growth factor (VEGF)40.