Shiitake's therapeutic uses
Shiitake mushrooms, native to East Asia, have a long history of use in traditional medicine, particularly in Japan and China, where they are recognized for their potential health benefits. These mushrooms are believed to possess various therapeutic properties, including cancer prevention, immune support, and cardiovascular health enhancement. The primary bioactive compound in shiitake, lentinan, has garnered attention for its possible immune-stimulating and anticancer effects, particularly in conjunction with chemotherapy for certain cancers. Additionally, some studies suggest that shiitake may help lower cholesterol and blood pressure, contributing to cardiovascular well-being.
Shiitake mushrooms are commonly consumed in food or taken as an extract, with recommended dosages varying from 1 to 3 grams three times daily. While they are generally regarded as safe when consumed as food, concentrated extracts may pose safety concerns, especially for vulnerable populations such as pregnant women or those with severe health conditions. Despite their popularity and nutritional value, the clinical evidence supporting many of shiitake's proposed health benefits remains limited and largely inconclusive. As such, while shiitake may contribute to a healthy diet, its effectiveness in treating or preventing specific ailments is not firmly established.
Shiitake's therapeutic uses
DEFINITION: Natural plant product used to treat specific health conditions.
PRINCIPAL PROPOSED USES: Cancer prevention, cancer treatment support, genital warts, immune support, cardiovascular health, anti-inflammatory, liver health, anti-aging
Overview
The shiitake mushroom is native to Japan, China, and other East Asian countries. It grows naturally on fallen trees in forests, hence the common name black forest mushroom. Deliberate cultivation of shiitakes for both food and medicine is of ancient origin.
During the Ming Dynasty (1368-1644), shiitake developed a reputation as a tonic, a substance said to increase energy, prevent disease, aid recovery from illness, and slow bodily deterioration caused by aging. It was also used more specifically to treat respiratory illnesses, liver diseases, and intestinal infestation with worms. The soft fleshy cap (fruiting body) is the part used medicinally.
Therapeutic Dosages
When taken orally, shiitake mushrooms are most commonly used in the form of an extract: Lentinus edodes mycelium extract (LEM). The typical dose of LEM is 1 to 3 grams three times daily. Purified lentinan (a constituent of shiitake) is suitable for intravenous use and is licensed as a pharmaceutical in Japan; it is not available in the United States.
Therapeutic Uses
Few proposed uses of shiitake mushroom or shiitake mushroom extracts are supported by reliable scientific evidence. The investigation of shiitake focuses primarily on the potential immune-stimulating and anticancer effects of some of its constituents, most prominently lentinan, a polysaccharide substance in the beta-glucan family. Limited evidence from case reports and highly preliminary human studies hints that the use of intravenously injected, purified lentinan might enhance the effectiveness of chemotherapy for stomach cancer, pancreatic cancer, and ovarian cancer. Lentinan products designed for oral use should not be injected.
One study found hints that oral lentinan might reduce recurrence rates of genital warts following laser surgery. Some studies suggest shiitake mushrooms may promote cardiovascular health by lowering cholesterol and blood pressure. In a 2021 double-blind, placebo-controlled study, participants taking shiitake mushroom bars saw a reduction in triglycerides compared to the placebo group. The antioxidant properties found in shiitake mushrooms may also provide protection from cellular damage that can lead to premature aging. Extremely weak evidence hints that lentinan might have immune-stimulating and liver-protective effects. In an animal study, lentinan reduced the risk of colon cancer in mice with ulcerative colitis. Another study failed to find oral shiitake extract helpful for the treatment of prostate cancer. Though the shiitake mushroom is a healthy food packed with vitamins and nutrients which aid in a healthy lifestyle, the ability of the mushroom and its extracts to heal ailments and cure diseases is unproven.
Safety Issues
As a widely eaten food, shiitake mushroom is believed to be fairly safe. As with any food, allergic reactions can occur.
The safety of concentrated shiitake extracts, however, is less clear. Safety in pregnant or nursing women, young children, and people with severe liver or kidney disease has not been evaluated.
Bibliography
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DeVere White, R. W., et al. "Effects of a Mushroom Mycelium Extract on the Treatment of Prostate Cancer." Urology, vol. 60, 2002, pp. 640-644.
Kupfahl, C., G. Geginat, and H. Hof. "Lentinan Has a Stimulatory Effect on Innate and Adaptive Immunity Against Murine Listeria monocytogenes Infection." International Immunopharmacology, vol. 6, 2006, pp. 686-696.
"Lentinan." Memorial Sloan Kettering Cancer Center, 20 Oct. 2023, www.mskcc.org/cancer-care/integrative-medicine/herbs/lentinan. Accessed 16 Sept. 2024.
"7 Health Benefits of Mushrooms." UCLA Health, 24 Jan. 2022, www.uclahealth.org/news/article/7-health-benefits-of-mushrooms. Accessed 16 Sept. 2024.
"Shiitake Mushroom." Memorial Sloan Kettering Cancer Center, 14 Feb. 2023, www.mskcc.org/cancer-care/integrative-medicine/herbs/shiitake-mushroom. Accessed 16 Sept. 2024.
Stamets, Paul, et al. Fantastic Fungi: How Mushrooms Can Heal, Shift Consciousness, & Save the Planet. Earth Aware, 2019.