Turkey tail mushroom (Trametes versicolor) is a type of mushroom that is being studied for its immunostimulant and anti-tumor properties.
This medicinal mushroom has a broad spectrum of physiological activities and has been recognized and used for thousands of years in traditional medicine, especially throughout Asia (1). Turkey tail mushroom is rich in the polysaccharide, polysaccharide K (PSK) and polysaccharide-peptide (PSP), which possess powerful immune-boosting properties.
When used as an adjuvant cancer therapy, PSK appears to improve survival rates in patients with certain types of cancer, such as gastric, colorectal and esophageal cancer (2).
Turkey tail mushroom has powerful immune-boosting properties. In a clinical study published in International Immunonopharmacology, researchers investigated if regular consumption of turkey tail and Danshen capsules (a Traditional Chinese Medicine used for circulatory and heart health) could improve cellular immunity in healthy subjects.
It was concluded that in 100 healthy participants, regular use of both supplements could be beneficial for immunological functions by potential enhancement of cell-mediated immunity.
There was no evidence of adverse effects (3).
Turkey tail mushroom may boost immunity in people with certain cancers. Cancer treatments can weaken the immune system, leaving the body vulnerable to infection and the ability to fight foreign substances and disease.
According to the authors of a study published in The American Journal of Chinese Medicine, the combination of turkey tail and Danshen capsules can be beneficial for promoting immunological function in post-treatment of breast cancer patients.
Eighty-two patients with breast cancer took part in the study and were recruited to take turkey tail (50 mg/kg body weight, 100% polysaccharide-peptide) and Danshen (20 mg/kg body weight) capsules every day for a total of 6 months (4).
Turkey tail may have anti-tumor effects. Researchers set out to evaluate the effects of 28-day use of polysaccharide-peptide extracted from turkey tail in patients who had completed conventional treatment for advanced non-small cell lung cancer.
Thirty-four patients participated in the study, and treatment appears to be associated with slower deterioration in patients with this type of lung cancer.
In another study, scientists investigated the benefits of oral polysaccharide K with tegafur/uracil (chemotherapy drug combination) as an adjuvant therapy in stage II and III colorectal cancer.
The treatment period lasted 2 years and the following promising results were noted: the 5-year survival was 81.8 percent in the polysaccharide K group and 72.1 percent in the control group.
In stage III patients, disease-free and overall survivals in patients receiving polysaccharide K were increased significantly: 60 percent and 74.6 percent in the polysaccharide K group as compared with 32.1 percent and 46.4 percent in the controls (5).
In a study of patients who had undergone surgery for colorectal cancer, polysaccharide K was found to be useful as a maintenance therapy. The rate of patients in remission was significantly higher in the treatment group than in the placebo group. The survival rate of patients was also significantly higher than in the control group (6).
While the results of these studies are hopeful, studies on hepatocellular carcinoma and leukemia produced mixed results. Further studies are needed.
Turkey tail may provide gut protection. Certain bacteria in the gut can prevent and treat many common diseases. About 100 trillion bacteria, both good and bad, live inside the digestive system. Within those trillions of gut bacteria are about 1,000 different species, represented by some 5,000 distinct bacterial strains. Everyone’s gut microbiota is unique, but there are certain combinations and collections of bacteria that are found in healthy individuals (7).
The microbial flora of the intestines plays a critical role in maintaining intestinal health and in the development of a wide variety of disorders such as antibiotic associated diarrhea and inflammatory bowel disease.
Prebiotics are foods that act as food for human microflora. Prebiotics are used with the intention of improving the balance of these microorganisms (8). Turkey tail has been speculated to have prebiotic activity and was put to the test in a 2014 study.
In that study, researchers compared the effects of polysaccharide-peptide extracted from turkey tail, to those of the antibiotic, amoxicillin, on the human gut microbiome.
It was concluded that amoxicillin alters the microbiome and recovery from this disruption can take several weeks. Polysaccharide-peptide acts as a prebiotic to modulate human intestinal microbiome composition (9).
An in vitro study found that turkey tail extract modified gut bacteria composition by increasing populations of beneficial bacteria like Bifidobacterium and Lactobacillus while reducing potentially harmful bacteria, such as Clostridium and Staphylococcus.
Turkey tail may protect against several common strains of bacteria. Several in vivo animal studies show the antimicrobial activity of turkey tail mushroom extracts against prevalent pathogens, such as E. coli, P. aeruginosa, S. aureus, Candida albicans, Klebsiella pneumoniae, L. monocytogenes and Streptococcus pneumoniae.
Methanol extracts provide the strongest inhibitory activity. Polysaccharide K and various polysaccharide–peptide complexes as well as terpenoids and polyphenols are considered to be mainly responsible for these effects (10).
Adverse reactions to turkey tail are rare and short-term use has been shown to be well-tolerated in studies performed so far.
According to Memorial Sloan Kettering Cancer Center, passage of dark colored stools, darkening of fingernails, and low-grade hematological and gastrointestinal toxicities have been reported when used in conjunction with chemotherapy agents (11).
Nausea, vomiting and loss of appetite have also been reported, but it is unclear if such effects are caused by turkey tail mushroom or by the chemotherapy treatment.
Further studies are needed before recommending the proper dosage, especially when used in combination with chemotherapy. As with other supplements, consult with a physician before use.
Turkey tail mushroom is a medicinal mushroom with a broad spectrum of physiological activities that has been used for thousands of years in traditional medicine. It contains antioxidants and several compounds, namely polysaccharide K (PSK) and polysaccharide-peptide (PSP) which give it is immune boosting property, especially in those fighting cancers. It also has anti-tumor activity.
Turkey tail may also help improve gut bacteria balance and aid in the fight against several common strains of bacteria.
It appears to be mostly well-tolerated in studies; there have been some reports of dark colored stools, darkening of fingernails, nausea, vomiting and loss of appetite.