Medicinal mushrooms have been used in Asia for centuries mainly to treat infections and more recently, pulmonary disease and cancer. Various types of medicinal mushrooms have been approved complements to standard cancer therapy in Japan and China for the past 30 years. Adverse effects seem minimal and while the benefits of medicinal mushrooms seem promising, a clear understanding of which mushroom or which mushroom extract will benefit which patient and how is still lacking.1
Part of the challenge in studying mushrooms is that there are 1000s of species and more than 100 species of medicinal mushrooms currently being used in Asia. Commonly used species include Ganoderma lucidum (reishi), Trametes versiclor or Coriolus versicolor (turkey tail), Lentinus edodes (shitake) and Grifola frondosa (maitake). 1
Many studies seem to agree that mushrooms may exert their positive effects by enhancing or stimulating our own immune system. In the case of cancer, the immune system can be stimulated to destroy cancer cells. Researchers believe this effect is caused by the presence of high-molecular-weight polysaccharides in the mushrooms. These polysaccharides can be extracted and sold in capsule form but extraction method, agricultural practices and concentration are not necessarily regulated.1,2
Studies in humans have shown positive effects for those with various types of cancer. These effects include reducing tumor size, reducing the side effects of chemotherapy and radiation therapy and extending survival time. However, results are not universal. For example, turkey tail seems to help those with gastric, colorectal and esophageal cancers. However, for those with leukemia, breast or hepatocellular cancers, results were inconclusive. 1
Of course, studies in veterinary medicine are sparse. One study, published in 2007, looked at using maitake mushroom as a treatment for dogs with high-grade lymphoma. Fifteen family dogs took part in the study and unfortunately no objective responses were seen in any of these dogs. Two of the dogs developed spontaneous bleeding (hyphema, hematuria, petechia) that could not be explained with routine laboratory testing (platelet count, prothrombin time, activated partial thromboplastin time, fibrinogen concentration and measurement of fibrin degradation products). It is unclear as to what caused the bleeding – maitake mushroom extract, lymphoma or something else.3
Another study, published in 2012, looked at using turkey tail mushroom as a treatment for 15 dogs with splenic hemangiosarcoma who have already undergone surgery. It is unclear if the diagnosis was confirmed by more than one pathologist. This is important since hemangiosarcoma can sometimes be misdiagnosed. That study concluded those dogs who received high concentrations of turkey tail survived longer than those who received smaller concentrations. No adverse events were appreciated in any of the dogs. This is a promising result in a small number of patients. This study was funded by Chinese Medicine Holdings, LTD.4
- Memorial Sloan Kettering Cancer Center (April 12, 2019). Coriolus Versicolor. Retrieved from https://www.mskcc.org/cancer-care/integrative-medicine/herbs/coriolus-versicolor.
- National Cancer Institute. (January 17, 2019). “Medicinal Mushrooms (PDQ®)–Patient Version was originally published by the National Cancer Institute.” Retrieved from https://www.cancer.gov/about-cancer/treatment/cam/patient/mushrooms-pdq.
- C. Griessmayr, M., et al. Mushroom-Derived Maitake PETfraction as Single Agent for the Treatment of Lymphoma in Dogs. J Vet Intern Med 2007;21:1409-1412.
- Brown, C. and Reetz, J. Single Agent Polysaccharopeptide Delays Metastases and Improves Survival in Naturally Occurring Hemangiosarcoma. Evid Based Complement Alternat Med. 2012;2012: 384301.