Shiitake (Lentinula edodes)

Lentinula edodes (Shiitake) is an edible mushroom indigenous to East Asian that has been used for culinary and medicinal purposes for hundreds of years. Shiitake is now a popular mushroom worldwide but is still most commonly found in Asian supermarkets. They can be eaten fresh, dried, or taken as a supplement. (1) China was first to begin cultivating Shiitake about 1,200 years ago. It is found growing wild in the mountainous regions of China, Japan, Indonesia, and Taiwan. The mushrooms are naturally grown on fallen and decaying trees but can also be grown on an artificial substrate. In Japan and China the chemicals found in Shiitake have been analyzed for medicinal properties. Extracts have been used in treating cancer, and claims have been made that they reduce cholesterol, enhance sexual drive, improve longevity, kill viruses, and improve circulation. (2) Shiitake mushrooms are low in calories and contain many vitamins, such as vitamin B and D2, minerals, and other health-promoting compounds. The amount of bioactive ingredients in Shiitake mushrooms can vary based on how and where they were grown, stored, and prepared.

Anti-Cancer Properties: The several polysaccharides found in Shiitake may also have anti-cancer effects. The polysaccharide credited for the anti-cancer effects in Shiitake mushrooms is lentanin. Lentanin helps fight tumors and inhibits the growth of some cancer cells. In China, an injectable form Lentanin is used alongside other cancer treatments to enhance the cancer treatments effectiveness as well as boost the immune function and quality of life for someone being treated for cancer. (7) Clinical trials with 2 2 mg/week Lentanin alongside chemotherapy showed a significant advantage over chemotherapy alone in terms of survival rates of patients with gastric cancer. (10)

Heart Health: There are several compounds found in Shiitake mushrooms that may lower cholesterol and promote overall heart health. Shiitake contains Eritadenine, a compound that inhibits an enzyme involved in producing cholesterol, Sterols, molecules that block cholesterol absorption in the gut, and Beta Glucans, a fiber that can lower cholesterol. Consumption of Shiitake can help lower cholesterol levels which lowers risk of heart disease and high blood pressure by reducing fat deposits in blood vessels. (4) A study performed on lab rats that were fed a high-fat diet demonstrated that those given Shiitake developed less fat in their livers, less plaque on their artery walls, and lower cholesterol levels than those that didn’t eat any mushrooms. (3) Another study showed the ingestion of dried Shiitake (9 g/day) decreased serum cholesterol 7-10% in patients suffering from hypercholesterolemia. (11)

Immune Health: Shiitake mushrooms contain several polysaccharides such as lentinans and other beta glucans that may boost the immune system, protect against cell damage, and boost white blood cell production to fight off microbes (a bacterium causing disease or fermentation). A study done on 52 healthy adults from ages 21-41 concluded that patients that consumed Shiitake twice daily for a month showed improved immune health and reduced inflammation. (5) Additionally, an inevitable factor that contributes to a weakened immune system is age. Shiitake supplementation has been shown to reverse age-related decline in immune function. (6)

Clinical Summary:

Main Applications: Cancer, cholesterol control

Key Component: Polysaccharides and eritadenine

Dosage: 2-6 g/day polysaccharide extract for immune support. 9 g/day dried fruit body for cholesterol support.

Side Effects: Some cases of dermatitis from eating or handling the raw mushroom, but no such reports from supplementation. Ingestion of Shiitake powder over a long period of time may cause digestive problems. (4)