Turkey Tail

Natural History

(Ecology, where and how it grows)

Occurring in tropical, subtropical, and temperate zones, Trametes versicolor aka Turkey Tail mushroom is a species commonly found throughout the United States and North America, as well as Asia and Europe. 

A polypore fungi, the T. versicolor propagates via wind-blown haploid spores. When such spores land in a beneficial environment, i.e. one containing another fungi germling, the two will fuse their hyphae and mix their cell contents in a stage of the life cycle called plasmogamy, after which each of the cells within “the original germlings should now contain two different nuclei that are unfused… The fungus stays in this dikaryotic state for most of its life.” [4] 

T. versicolor is a polypore, a member of the Polyporaceae which counts more than 100 genera in its family. Most Polyporaceae members have vertical pores on the underside of their caps, ranging vastly in size, from 10 per millimeter to 2 millimeter per pore! Polypores typically have hard exteriors and an atypical “non-mushroom” shape. Their growth on wood, as wood decomposers, helps to distinguish them from other fungi. 

Turkey Tail fungi are commonly found on fallen trees and tree stumps, and serve the role of breaking down wood and “recycling the nutrients and minerals” in the wood and releasing them into the soil over time, sometimes many hundreds of years. T. versicolor causes a white rot on wood, as the fungus decays the lignin and leaves the cellulose behind. [33]

Ethnomycology

(The Cultural and Sociological Impact of this Species)

The benefits of Turkey Tail have been known in Asia for thousands of years. It is included in the Chinese Compendium of Materia Medica by Li Shizhena, a book published more than 3000 years ago, which refers to the fungi as a folk medicine with a long history of use. [35] In traditional Chinese medicine (TCM), they believe that the mushroom helps fight infection and supports immune system function. During the 15th century, the Chinese drank Turkey-Tail-infused tea which was thought to help strengthen their bones and tendons.

Quick Facts

View Verdant Leaf’s Turkey Tail mushroom products for the whole family.

Health Benefits

Gut Health

The naturally-occurring prebiotics PSK and PSP in Turkey Tail support digestion and help your gut biome thrive. Found in the fruiting body of Trametes versicolor, polysaccharide Krestin (PSK) is a prebiotic, a peptide, polysaccharide, and a protein complex. Found in the mycelium, polysaccharopeptide, aka polysaccharide peptide (PSP), is also a prebiotic, a peptide, and polysaccharide. The chemical structures of PSP and PSK are similar; the most notable differences being hamnose and arabinose in PSP and fucose in PSK (more on that in the Cancer section below).

For optimal health, our microbiome needs both prebiotics and probiotics. In order for the gut to function well, it needs an array of healthy bacterial enzymes to properly digest foods. These specific strains of healthy bacteria, i.e. live organisms (lactobacillus acidophilus, bifidobacterium, saccharomyces, streptococcus, enterococcus, escherichia, and bacillus), are commonly referred to as probiotics. Probiotics are added and replenished through eating an array of healthy foods, especially fermented products (yogurt, kombucha, kimchi, sauerkraut, etc.). 

Prebiotics, on the other hand, are not live organisms, but as The Mayo Clinic explains, are “specialized fibers” which “act like fertilizers that stimulate the growth of healthy bacteria in the gut.” Prebiotics are needed to support and maintain the gut’s colonies of probiotics. [26]

In a research support study published in 2013, Turkey Tail was shown to increase two strains of healthy bacteria, namely bifidobacterium and lactobacillus, and reduce the well-known pathogens clostridium and staphylococcus. [40]

In 2014, a randomized clinical trial on the effects of PSP versus the effects of amoxicillin on the gut microbiome was conducted. Twenty-four healthy volunteers were randomized to receive PSP, amoxicillin, or no treatment (as the control group). Among the twenty-two who successfully completed the protocol, PSP was shown to lead to “clear and consistent microbiome changes consistent with its activity as a prebiotic.” While the “antibiotic amoxicillin alters the microbiome” and “caused substantial microbiome changes, most notably an increase in Escherichia/Shigella” … PSP from Turkey Tail “acts as a prebiotic to modulate human intestinal microbiome composition.” [27]

While the above research is considerable, we are by no means anywhere near the end. In fact, we’ve only just started learning the specifics of why Turkey Tail supports gut health. In July 2022, Nature published an expanded reference map of the human gut microbiome which revealed literally hundreds of previously unknown species. Science is currently at the frontier of fully understanding the gut and its significant role in overall health and wellbeing. [19] 

Supports Organ Function

Among other things, Turkey Tail is an anti-genotoxin that has been shown to improve organ function by helping to repair cellular damage. A 2015 study found concentrations of Turkey Tail were “able to stimulate” a “genoprotective response of cells contributing to enhanced immune function, toxin removal, and strengthening,” and thereby serve as a “strong antigenotoxic” agent.

Genotoxicity is the destruction of the “integrity of the genetic material of the cells (DNA, RNA).” Genotoxins are “chemical agents that can cause chromosomal damage.” If present in reproductive cells, such damage can potentially cause a deleterious germline mutation, meaning the offspring could suffer from a heritable disease or birth defect. In somatic cells (non-reproductive cells) genotoxicity “may result in somatic mutation, which may lead to malignant transformation (cancer).” [17]

Immunity

Along with Turkey Tail’s support to facilitate bacteria balance in the gut, which contains 70–80% of the human body’s immune cells, it further supports the immune system in diverse ways.

Turkey Tail’s polysaccharides-Krestin (PSK) and polysaccharide peptide (PSP) are powerful metabolites known for their ability to boost the immune system and reduce inflammation. They have also been shown to activate immune system cells like dendritic cells, that “link innate and adaptive immunity” and play a critical role in “the induction of protective immune responses against pathogens.” [21]

Furthermore, both PSK and PSP are “biological response modifiers (BRMs).” Also known as immunomodulators, they “target the disease-causing mechanism” and are often used in the treatment of “autoimmune diseases as first-line medications or after the failure of conventional agents.” [31]

PSK has been shown to suppress inflammatory responses by protecting against harmful bacteria through boosting macrophages, the immune cells that surround and kill microorganisms, remove dead cells, and stimulate the action of other immune system cells. [25]

Over the past four decades, PSP has also been shown to possess immunomodulatory and anti-tumor mechanisms. Immunomodulators are substances that stimulate or suppress the immune system and may help the body fight cancer, infection, or other diseases. [6]

While clinical studies support PSP being a potential immunotherapeutic (immunomodulator), further analysis of the complicated chemical and multiple pharmacological properties of PSP need to be further evaluated.

Cancer

The exact agents within PSP that are responsible for the beneficial effects it supports are still being studied. In China and Japan, it has been used as an adjuvant therapy in the treatment of several kinds of cancer, especially those of the stomach, colon, and rectum. Over the past decade, immunotherapy in cancer care has been gaining momentum in the United States. 

As stated in the section on Immunity, PSP has also been shown to possess immunomodulatory and anti-tumor mechanisms. Immunomodulators are substances that stimulate (or suppress) the immune system and may help the body fight cancer, infection, or other diseases.

Specifically, polysaccharopeptide (PDP) “increases the expression of cytokines and chemokines (tumor necrosis factor-α TNF-α), interleukins (IL-1β and IL-6),” prostaglandin E, and histamine, and enhances “dendritic and T-cell infiltration into tumors,” as well as alleviates the adverse effects associated with chemotherapy. [6]

Published in the Journal of Clinical Oncology in 2010, twenty one patients with stage III gastric cancer participated in a randomized controlled trial. Post operation, participants received the common chemotherapy drug combination tegafur/uracil (UFT) and isolated PSK, or only tegafur/uracil without PSK. In the group that received PSK, the 3-year overall survival was 62.2%, and 12.5% in the control group. 

Prior to operation, among patients “there were no significant differences in the proportions of Th1 cells, Th2 cells, Th1/Th2 ratio, CD56(+) T cells, CD57(+) T cells, NK cells, and CD4(+)CD25(+) T cells” between the two randomized and controlled groups. 

Post operation, the group that received PSK, saw a significant decrease in CD57(+) T cells. High CD57(+) has been recognized as an indicator of poor prognosis in patients with advanced gastric cancer. 

It was noted that in the “group treated with PSK + UFT” the 3-year survival of CD57-high patients was as great as that of CD57-low patients. The trial concluded that “PSK improves overall survival of stage III gastric cancer patients partly by inhibiting CD57(+) T cells.” [1]

In another randomized controlled trial that was later published in the journal Oncology, twenty patients with “curatively resected stage III gastric cancer” were assigned to receive “adjuvant therapy with the second-generation dihydropyrimidine dehydrogenase-inhibitory oral fluoropyrimidine” alone or in conjunction with PSK. 

Five weeks after receiving adjuvant therapy, T-cell apoptosis (cell death) was significantly higher in those who did not receive PSK. The study participants who received PSK showed significantly less apoptosis, demonstrating that PSK could “partially prevent the T-cell apoptosis” induced by the chemotherapy. [18]

The Department of Surgical Oncology, Kanazawa Medical University in Ishikawa, Japan, conducted a retrospective study on the survival rates of patients over 70 years of age, treated with UFT alone, or UFT plus PSK. They found the relapse-free survival rate of the “UFT-only group (control)” to be 47.8%, whereas the UFT plus PSK group “relapse-free survival rates were 76.2%.” The overall survival rate was “52.8% in the control group” which did not receive PSK, and “80.8% in the PSK group.” [37]

Oxidative Stress & Chronic Inflammation

Oxidative stress is “a phenomenon caused by an imbalance between production and accumulation of reactive oxygen species (ROS) in cells and tissues” and the ability to detoxify the system of these reactive products. As oxygen-containing molecules with one or more than one unpaired electron, aka “free radicals,” easily bind with other molecules in the human body, oxidation takes place. “Oxidation” is the term used to describe the series of chemical reactions that occur as free radicals react with other molecules in the body. [30]

Inflammation is a natural process of the immune system. When we sprain a wrist or ankle, or bump our head, “acute inflammation” takes place thereby delivering white blood cells to the site of injury to begin the healing process.

Due to diet, environmental factors, chemical exposure, medications, and other factors, chronic inflammation is the result of the body’s immune system continuously releasing white blood cells and thereby “attacking” what it perceives as a threat or “foreign adversaries.” [36] Chronic inflammation may be highly persistent and “continue to simmer under the surface” for many years. Oxidative stress and the resulting chronic inflammation is strongly correlated with the onset of various diseases and health conditions including obesity, diabetes, cardiovascular disease, chronic obstructive pulmonary disease, chronic kidney disease, hypertension, and cancer. [20]

Trametes versicolor is very high in antioxidants: chemicals that neutralize free radicals and thus prevent them from causing damage. [3] A study conducted in 2017 found nearly three dozen different antioxidants in T. versicolor, including an array of polyphenols and flavonoids (quercetin, baicalein, daidzein, amentoflavone, catechin, apigenin). [17] Furthermore, flavonoid antioxidants have been shown to support immune system health by stimulating the release of protective compounds. [28]

Turkey Tail for Pets & Animals

In a study conducted by two faculty members of the University of Pennsylvania School of Veterinary Medicine, Dorothy Cimino Brown, DVM, MSCE, professor and chair of the Department of Clinical Studies, and Jennifer Reetz, attending radiologist of the Department of Clinical Studies, PSP derived from Trametes versicolor aka Turkey Tail mushroom was shown to lengthen the survival time of dogs with naturally occurring hemangiosarcoma. 

Fifteen dogs diagnosed with hemangiosarcoma participated in the trial. Via a computer-generated randomization sequence, they were divided into three groups: one group treated with a low dose PSP of 25 mg/kg/day. The second group was treated with the medium dose PSP of 50 mg/kg/day. The third group was treated with a high dose of PSP of 100 mg/kg/day. Compounds were generated at an off-site pharmacy.

“The median time to development or progression of abdominal metastases was significantly delayed in dogs receiving 100 mg/kg/day” of PSP. Furthermore, there appeared to be a positive correlation between an increase in dose of PSP and survival time. “The median survival time increased as dose of PSP increased and high dose PSP provided the longest median survival times reported to date.” Dogs in both of “the two highest dose groups had median survival times longer than the longest median survival time reported in the literature to date.” Prior to this study, the longest median survival time was 86 days. In this study, dogs in the medium dose group had a median survival time of 117 days, while dogs receiving 100 mg/kg/day had a median survival time of 199 days. [5]

medicinal compounds

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