Several observational and small clinical studies indicate the potential of extracts from Turkey Tail/Yun Zhi/Coriolus versicolor mushrooms to improve the immune system and/or survival in patients with cancers such as breast, colorectal, gastric and lung cancers and reduce the risk of cancers such as prostate cancer, and Reishi/Ganoderma lucidum mushrooms to improve the host immune functions in cancer patients and reduce the risk of cancers such as colorectal cancers. However, these mushroom extracts cannot be used as first line cancer treatment, but only as an adjuvant alongside standard of care treatments after studying their interactions with specific chemotherapies. Studies also found that while increasing doses of Maitake mushroom extracts increased some immunologic parameters in cancer patients, it depressed others.
Medicinal Mushrooms for Cancer
Medicinal mushrooms have been used in different parts of the world, especially in Asia, for the treatment of various diseases. The popularity of medicinal mushrooms as an alternative medicine or an adjuvant therapy has been also increasing in cancer patients since many years. In fact, in China and Japan, medicinal mushrooms are approved as an adjuvant alongside their standard of care chemotherapy for cancer patients for more than 3 decades.
More than 100 types of mushrooms are being used for treating various diseases including cancer in Asia. The bioactive compounds present in each type of medicinal mushrooms are different and hence have diverse bioactivities. Some of the common examples of mushrooms which are popular for its association with cancer treatments are Agaricus blazei, Cordyceps sinensis, Grifola frondosa/Maitake, Ganoderma lucidum/Reishi, and Turkey Tail.
But do we have studies suggesting that including these mushrooms as part of the cancer patients’ diet may improve cancer outcomes or help lower cancer risk? Can we use these mushrooms as first line treatment for cancers?
Let us find out from some of the clinical and observational studies associated with some of these mushrooms, especially Turkey Tail/Yun Zhi/Coriolus versicolor Mushrooms, Reishi/Ganoderma lucidum Mushrooms and Maitake/Grifola frondosa mushrooms.
Mushroom consumption and Prostate Cancer
Study in Japanese Population
In a recent study published in 2020, the researchers from the Tohoku University School of Public Health and Tohoku University Graduate School of Agricultural Science in Japan and Pennsylvania State University and Beckman Research Institute of the City of Hope in the US evaluated the relationship between mushroom consumption and incident prostate cancer. They used dietary data from the Miyagi Cohort Study in 1990 and the Ohsaki Cohort Study in 1994, which involved 36,499 men who were aged between 40-79 years. During a follow-up period of 13.2 years, a total of 1204 cases of prostate cancer were reported. (Shu Zhang et al, Int J Cancer., 2020)
The study found that compared to the participants who consumed mushroom less than one servings per week, those who consumed mushroom frequently were associated with a decreased risk of prostate cancer. The risk reduction was approximately 8% for those who consumed 1-2 servings per week and 17% for those who consumed ≥3 servings per week. The study also highlighted that this association was more predominant in middle-aged and elderly Japanese men.
Based on these findings, the researchers concluded that regular intake of mushrooms might help in reducing the risk of prostate cancer.
Impact of White Button Mushroom (WBM) Powder Intake on serum Prostate Specific Antigen levels
Researchers from the City of Hope National Medical Center and Beckman Research Institute of the City of Hope in California carried out a study to evaluate the effects of white button mushroom powder on serum Prostate Specific Antigen levels. The study included a total of 36 patients with continuously rising PSA levels. (Przemyslaw Twardowski, et al, Cancer. 2015 Sep)
The study found that after 3 months of white button mushroom powder intake, PSA levels reduced in 13 out of 36 patients. The overall PSA response rate was 11% with no dose limiting toxicities post using white button mushroom powder. In two of the patients who received 8 and 14 gm/day of white button mushroom powder, complete response related to PSA was observed, with the PSA declined to undetectable levels for 49 and 30 months and in two other patients who received 8 and 12 gm/day, a partial response was observed.
Mushroom Consumption and Risk of Total and Site-Specific Cancers in U.S. population
In a study published in 2019, the researchers from Harvard T.H. Chan School of Public Health, Brigham and Women’s Hospital and Harvard Medical School in Boston and Dongguk University in South Korea evaluated the association of mushroom consumption with total and various site-specific cancer risks. For the analysis, they used data from 68,327 women from the Nurses’ Health Study (1986–2012) and 44,664 men from Health Professionals Follow-up Study (1986–2012) who were free from cancer during recruitment. During a mean follow up of 26 years, a total of 22469 cancer cases were reported. (Dong Hoon Lee et al, Cancer Prev Res (Phila)., 2019)
The study found no association between mushroom consumption and risk of 16 site-specific cancers in the U.S. women and men. The researchers suggested more prospective cohort/population-based studies to evaluate the association of mushroom intake with specific types of cancers in different racial/ethnic groups.
Turkey Tail/Yun Zhi/Coriolus versicolor Mushrooms
Turkey tail/Coriolus versicolor mushrooms grow on dead logs. Their medicinal extracts are produced from the mycelium and fruiting body of the mushroom and are used in cancer patients for improving their immune system. The key ingredients are beta-Sitosterol, Ergosterol and polysaccharopeptides which include Polysaccharide krestin (PSK) and Polysaccharide peptide (PSP) obtained from the mycelium of CM-101 and COV-1 strains of the fungus, respectively.
Impact of Turkey Tail/Yun Zhi/Coriolus versicolor Mushroom Consumption in Cancer
Hong Kong Study
Researchers from the Chinese University of Hong Kong, and Prince of Wales Hospital in Hong Kong did a meta-analysis to analyze the efficacy of Turkey Tail/Yun Zhi/Coriolus versicolor mushroom consumption on the survival of cancer patients from 13 clinical trials obtained from computerized database and manual search. (Wong L Y Eliza et al, Recent Pat Inflamm Allergy Drug Discov., 2012)
The study found that patients who used Turkey Tail mushroom along with their conventional cancer treatment had a significant improvement in survival, with a 9% absolute reduction in 5-year mortality, compared with those who only took the conventional anti-cancer treatment. The findings were evident in patients with breast cancer, gastric cancer, or colorectal cancer treated with chemotherapy, but not in esophageal and nasopharyngeal cancers.
This study however could not confirm which specific anti-cancer treatment may maximize the benefit from Turkey Tail/Yun Zhi/Coriolus versicolor mushroom.
Impact of Turkey Tail Mushroom Consumption in Breast Cancer Patients
In a study done by the researchers from the University of Minnesota in the U.S., they conducted a small phase 1 clinical study in 11 breast cancer patients who completed radiation therapy to determine the maximum tolerated dose of Turkey Tail Mushroom extract preparation when taken daily in divided doses for 6 weeks. 9 out of 11 breast cancer patients who received either 3 g, 6 g, or 9 g Turkey Tail Mushroom extract preparation completed the study. (Carolyn J Torkelson et al, ISRN Oncol., 2012)
The study found that up to 9 grams/day of a Turkey Tail Mushroom extract preparation was safe and tolerable in these breast cancer patients when given post their conventional cancer treatment. They also found that the mushroom extract preparation may improve the immune status in immunocompromised breast cancer patients following standard primary oncologic treatment. However, more well designed large scale clinical studies are required to establish these findings.
Impact of Turkey Tail Mushroom Ingredient /Polysaccharide krestin (PSK) in Colorectal Cancer Patients
A study conducted by the Fukseikai Hospital in Japan, the researchers compared the 10-year overall survival in colorectal cancer patients who underwent surgery, between those patients who received group oral fluoropyrimidines alone and those who received oral fluoropyrimidines in conjunction with Polysaccharide kureha/Polysaccharide krestin (PSK), a key active ingredient of Turkey Tail mushroom, for 24 months. They found that the 10-year survival rates for patients who received PSK along with their treatment was 31.3% higher than those who received the treatment alone. In colorectal cases with high grade lymphatic and venous invasion (cancer penetrating beyond the bowel wall), the improvement in overall survival was 54.7% which was even more significant. (Toshimi Sakai et al, Cancer Biother Radiopharm., 2008)
Another study done by the researchers from Gunma University, in Japan also found similar benefits of protein-bound polysaccharide K when taken along with cancer treatment tegafur in patients with stage II or III colorectal cancer. (Susumu Ohwada et al, Oncol Rep., 2006)
Impact of Turkey Tail Mushroom Ingredient Polysaccharide krestin (PSK) in Gastric Cancer Patients
A meta-analysis done by the researchers of the University Graduate School of Medicine evaluated the effect of immunochemotherapy on survival in 8009 gastric cancer patients who underwent surgery, from 8 randomized controlled trials. In this study they compared the results of chemotherapy and immunotherapy using the Turkey Tail Mushroom Ingredient – Polysaccharide krestin (PSK)- as an immunopotentiator. (Koji Oba et al, Cancer Immunol Immunother., 2007)
The findings from the meta-analysis suggested that adjuvant immunochemotherapy along with Polysaccharide krestin (PSK), the key active ingredient of Turkey Tail mushroom, may improve the survival of gastric cancer patients who underwent surgery.
Impact of Turkey Tail Mushroom Ingredient Polysaccharide krestin (PSK) in Lung Cancer Patients
Researchers from the Canadian College of Naturopathic Medicine and Ottawa Hospital Research Institute in Canada did a systematic review of Polysaccharide krestin (PSK), the key active ingredient of Turkey Tail mushroom, for the treatment of lung cancer. A total of 31 reports from 28 studies (6 randomized and 5 non-randomized controlled trials and 17 preclinical studies) were used for the analysis which was obtained through literature search in PubMed, EMBASE, CINAHL, the Cochrane Library, AltHealth Watch, and the Library of Science and Technology till August 2014. (Heidi Fritz et al, Integr Cancer Ther., 2015)
The study found improvement in median survival and 1-, 2-, and 5-year survival in nonrandomized controlled trial with PSK use. The study also found benefits in immune parameters and hematological/blood function, performance status and body weight, tumor-related symptoms such as fatigue and anorexia, as well as survival in randomized controlled trials.
The researchers concluded that Polysaccharide krestin (PSK), the key active ingredient of Turkey Tail mushroom, may improve host immune function (enhanced natural killer (NK) cell activity), reduce tumor-associated symptoms, and extend survival in lung cancer patients. However, larger well defined clinical trials are needed to establish these findings.
Reishi/Ganoderma lucidum Mushrooms
Reishi/Ganoderma lucidum mushrooms grow on trees and are used in cancer patients, especially in China and Japan, to strengthen the immune system. Some of the key active ingredients of Reishi mushrooms are Ergosterol Peroxide, Ganoderic acid, GPL, Linoleic acid, Oleic acid and Palmitic acid
Impact of Reishi/Ganoderma lucidum Mushroom Consumption in Cancer
Meta-analysis by Researchers from University of Sydney
Researchers from the University of Sydney in Australia did a systematic review to evaluate the clinical effects of Reishi/Ganoderma lucidum mushroom consumption on long-term survival, tumour response, host immune functions and quality of life in cancer patients, as well as adverse events associated with its use. For the analysis, data from 5 randomised controlled trials was obtained through literature search in Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, NIH, AMED, CBM, CNKI, CMCC and VIP Information/ Chinese Scientific Journals Database in October 2011. (Xingzhong Jin et al, Cochrane Database Syst Rev., 2012)
The analysis found that patients who received Reishi/Ganoderma lucidum mushroom extract alongside their chemo/radiotherapy were more likely to respond positively compared to chemo/radiotherapy alone. However, treatment with Reishi/Ganoderma lucidum mushroom extract alone did not have the same benefit as seen in combined therapy. Four of the studies also found that patients who received Reishi/Ganoderma lucidum mushroom extract alongside their treatment had relatively improved quality of life as compared to those who received only their cancer treatment.
The researchers concluded that Reishi/Ganoderma lucidum mushroom extract cannot be used as a first-line treatment for cancer. However, Reishi/Ganoderma lucidum mushroom extract may be administered as an adjuvant therapy alongside conventional treatment due to its potential of enhancing tumour response and stimulating immunity.
Impact of Reishi/Ganoderma lucidum mushroom extract in Patients with Colorectal Adenomas
Hiroshima University Hospital in Japan conducted a clinical trial on 96 patients with colorectal adenomas (precancerous lesions of the large bowel/precursor to colorectal cancer) to evaluate the impact of supplementing 1.5 g/day Reishi/Ganoderma lucidum mushroom extract for 12 months on the risk of developing colorectal cancers. 102 patients with colorectal adenomas were not supplemented with the Reishi/Ganoderma lucidum mushroom extract and were considered as control for the study.
The study found that while the number and size of adenomas were increased in the control group, these were found to be decreased in the colorectal adenoma patients who received Reishi/Ganoderma lucidum mushroom extract.
Based on the findings from the study, the researchers concluded that Reishi/Ganoderma lucidum mushroom extract may suppress the development of colorectal adenomas.
Impact of Ganoderma Lucidum polysaccharides in Patients with Lung Cancer
Researchers from the Massey University conducted a clinical study on 36 patients with advanced lung cancer to evaluate the impact of supplementing 5.4 g/day Ganoderma Lucidum polysaccharides for 12 weeks. The results from the study found that only a subgroup of these cancer patients responded to Ganoderma Lucidum polysaccharides in combination with chemotherapy/radiotherapy and showed certain improvements on host immune functions.
The researchers also suggested that large well defined studies are needed to explore the efficacy and safety of Ganoderma Lucidum polysaccharides when used alone or in combination with chemotherapy/radiotherapy in lung cancer patients. (Yihuai Gao et al, J Med Food., Summer 2005)
Impact of Ganoderma Lucidum polysaccharides in Patients with Advanced Stage Cancers
A previous study done by the same researchers from Massey University in New Zealand had evaluated the effect of using 1800 mg Ganoderma Lucidum polysaccharides thrice a day for 12 weeks on the immune function of 34 advanced-stage cancer patients. (Yihuai Gao et al, Immunol Invest., 2003)
The study found that Ganoderma Lucidum polysaccharides enhanced the immune responses in patients with advanced-stage cancer as measured by cytokine levels (increase in serum levels of IL-2, IL-6, and IFN-gamma; and decrease in IL-1 and tumor necrosis factor (TNF-alpha) levels), lymphocyte (cancer-fighting immune cell) counts and increased natural killer cell activity. However, they suggested more studies to evaluate safety and toxicity of Ganoderma Lucidum polysaccharides before recommending its use in cancer patients.
Maitake/Grifola frondosa Mushrooms
Maitake/Grifola frondosa Mushrooms grow in clusters at the base of trees, particularly oaks. Some of the key active compounds of maitake mushrooms are polysaccharides, ergosterol, magnesium, potassium and phosphorus and vitamins B1 and B2. Maitake mushrooms are used to fight tumors, stimulate the immune system, and lower blood sugar and lipid levels.
Impact of Maitake mushroom extract Use in Cancer
Impact of Maitake mushroom extract use in Cancer Patients with Myelodysplastic Syndromes
A phase II clinical study done by the researchers of the Integrative Medicine Service, Memorial Sloan Kettering Cancer Center in the US evaluated the effects of supplementing Maitake mushroom extract (3 mg/kg) for 12 weeks on innate immune function in 18 Myelodysplastic Syndromes ( MDS) patients. The study found that Maitake mushroom extract was well tolerated in these cancer patients and also increased basal neutrophil and monocyte function in vitro, suggesting the immunomodulatory potential of Maitake mushroom extract in MDS. (Kathleen M Wesa et al, Cancer Immunol Immunother., 2015)
Impact of Maitake Mushroom Polysaccharide in Breast Cancer patients
In a phase I/II clinical trial done by the researchers of the Integrative Medicine Service, Memorial Sloan Kettering Cancer Center in the US, they evaluated the immunological effects of Maitake Mushroom Polysaccharide in 34 postmenopausal breast cancer patients who were free of disease after initial treatment. The patients received 0.1, 0.5, 1.5, 3, or 5 mg/kg of oral maitake mushroom extract twice daily for 3 weeks. (Gary Deng et al, J Cancer Res Clin Oncol., 2009)
The study found that the oral administration of maitake mushroom polysaccharide extract was associated with both immunologically stimulatory and inhibitory effects in peripheral blood. While increasing doses of Maitake mushroom extracts increased some immunologic parameters, it depressed others. Hence, the researchers highlighted that Cancer patients should be warned of the fact that Maitake mushroom extracts have complex effects which may depress as well as enhance immune function at different concentrations.
Different studies suggest that mushrooms like Turkey Tail mushrooms may have the potential to improve the immune system and/or survival in patients with cancers such as breast, colorectal, gastric and lung cancers and reduce the risk of cancers such as prostate cancer, and Reishi/Ganoderma lucidum mushrooms may have the potential to improve the host immune functions in certain cancer patients and reduce the risk of cancers such as colorectal cancers. However, these mushroom extracts cannot be used as first line cancer treatment, but only as an adjuvant alongside chemotherapy and radiotherapy after studying their interactions with these standard of care chemotherapies. Also, while increasing doses of Maitake mushroom extracts increased some immunologic parameters in cancer patients, it depressed others. More well-designed larger clinical trials are required to evaluate the efficacy and safety/toxicity of all these medicinal mushrooms when used with specific chemotherapies and other cancer treatments.
Cancer patients often have to deal with different chemotherapy side effects which affect their quality of life and look out for alternative therapies for cancer. Taking the right nutrition and supplements based on scientific considerations (avoiding guesswork and random selection) is the best natural remedy for cancer and treatment related side-effects.