The most abundant forest medicine
Trametes versicolor, also known as Coriolus versicolor, Turkey Tail, Yun-Zhi (in Chinese) and Karawaratake (in Japanese).
Turkey Tail is a commonly found mushroom with remarkable medicinal properties, especially with regards to cancer treatment. Paul Stamets, a publicly known mycologist, frequently shares his story of how Turkey Tail extracts in combination with chemotherapy, may have saved his mother’s life.
In June 2009 his mother, then 83 years old, was diagnosed with advanced, metastatic inflammatory breast cancer. After diagnosis she began chemotherapy with Taxol and Herceptin and was also put on a trial to take Turkey Tail mushrooms alongside these too. The Turkey Tail capsules consist of activated, freeze-dried, organic mushroom mycelium, containing polysaccharides (beta-glucans, arabinoxylane, glucose, xylose, galactose, mannose, glycoproteins, ergosterols, triterpenoids, and other myconutrients).
The chemotherapy regimen was completed by his mother in December of 2009, and at that time she continued Herceptin maintenance therapy every 3 weeks. She also continued to take 4 g daily of turkey tail mushrooms and added a combination mushroom formula consisting of 17 species of activated, freeze-dried, organic mushroom mycelium, containing polysaccharides (beta-glucans, arabinoxylane, glucose, xylose, galactose, cordycepic acid, glycoproteins, ergosterols, triterpenoids, and other myconutrients).
This is a story with a happy ending. At the time of writing this, his mother continues to live an active life and is disease-free. Stamets believes his mother’s recovery is down to the immune modulation activity of the turkey tail mushrooms. This characteristic of Turkey Tail he believes enhances the ability of the patient's immune system to discover the tumour, thereby increasing the effectiveness of certain chemotherapy.
Description
T.versicolor are non-edible, but safe to consume, bracket fungi with a history of use in Asia as a nonspecific immune modulator. They are called bracket fungi because they form thin structures in concentric circles and grow almost everywhere trees are found. Their colourful concentric circular rings look like the fan of a turkey’s tail feathers, hence their name. They are small, growing up to four inches wide and can be found on dead logs, stumps, tree trunks and branches through the wooded temperate zones of Asia, Europe and North America.
They are thin and hard, with a texture described as tough and leathery. Interestingly, this mushroom belongs to the Polyporaceae family, meaning that it has pores on the underside of the mushroom instead of gills.
The Turkey Tail fungus is often listed as being one of the most common fungi in North American woods. But if you are interested in foraging for Turkey Tail mushrooms be aware that there are other species that look similar to it and thus use caution. Below, the first image is a zoomed-in image of the underside of Trametes versicolor. The keen-eyed amongst you will notice that it looks like the underside of a Birch Polypore with its multiple small pores. These pores are in fact a way to tell the difference between Trametes versicolor and Stereum ostrea, the False Turkey Tail fungus. The second image is that of Turkey Tail mushrooms from above.
Immunomodulating chemicals - PSK and PSP
Traditionally, our ancestors boiled mushrooms in water to make soothing tea. Boiling helps kill contaminants, softens the flesh, and extracts rich soluble polysaccharides locked within the fungi. In Trametes versicolor’s case, boiling would release two well studied and therapeutic polysaccharides; polysaccharide peptide (PSP) and polysaccharide K (PSK).
PSK
PSK has been used in Japanese medicine since the 1980s for treating several types of cancer and it is recognized as the best-selling anti-cancer drug in Japan as a complement to surgery, chemotherapy and radiotherapy.
PSK, also known as Krestin, is highly bioactive and can be found in the bone marrow, salivary gland, brain, liver, spleen, and pancreas in mice and rabbits within 24 hours of administration. Once absorbed by the body, PSK induces immunomodulation, increasing certain inflammatory molecules like TNF-α, IFN-γ, IL-2, IL-12 and IL-8.
The increase in IL-8 and IL-12 concentration after PSK induction confirms the effect on certain white cells such as lymphocytes, monocytes and macrophages circulating in the blood. The immunomodulatory effect of PSK is associated with the IL-12-dependent increase in the CD4+ Th1 cell response to tumour cells.
PSK also stimulates a form of T cell called Tγδ lymphocytes, which are a small but significant population of T cells in the antitumor immune response. The higher the percentage of Tγδ cells the better the prognosis, as these T cells infiltrate and help destroy tumour cells. PSK also stimulates natural killer (NK) cells, a type of white cell part of the evolutionary older adaptive immune system. NK cells increase tumour death through antibody-dependent activation.
PSP
PSP was discovered more recently in China and it is considered as a candidate with strong potential in drug development for the treatment and prevention of human cancers because of its immunological properties as well as its ability to act selectively on cancerous cells.
PSP is structurally similar to PSK and thus shows similar immunological activity. PSP has been shown to stimulate the expression of toll-like receptor TLR4, which is an immunological protein in the innate immune system. PSP also induces immunological messengers IL-1β, IL-6, TNF-α.
Β-glucan
What PSP and PSK both share is that they both contain the common, most biologically active component – β-glucan. β-glucan activates toll-like receptors TLR and TLR4 and this, in turn, activates a series of immune cells, such as monocytes, macrophages, NK cells, dendritic cells.
β-glucans are also interesting as they are not readily digestible by the intestinal enzymes of humans. They, therefore, remain in the gut until being utilised by colonic microbiota or excreted in the stools. Some of these indigestible dietary glycans can modify the intestinal bacteria in humans and modulate the immune system. β-glucans, therefore, act as a prebiotic, enhancing the growth of beneficial microbes in the gut.
One study noted that the ingestion of PSP promoted the growth of beneficial bacteria within the gut like Bifidobacteria and Lactobacilli, whilst reducing harmful bacteria like Clostridium, Staphylococcus and Enterococcus. This may be why Turkey Tail is also known to reduce gut inflammation.
Anti-cancer properties through immunomodulation
These immunomodulatory properties of both PSK and PSP are thought to have anti-cancer effects.
Numerous in vitro studies have reported that PSP and PSK can inhibit the proliferation of leukaemia, lymphoma, hepatoma, breast, lung and prostate tumour cell lines. One meta-analysis of patients with colorectal cancer showed that the addition of PSK to adjuvant therapy improves overall survival (OS) and disease-free survival (DFS). In the studies on the Asian population, an increase in 5-year survival was observed in patients with recurrent breast cancer after adding PSK to standard oncological treatment).
Monoclonal antibodies, such as trastuzumab combined with β-glucan have been shown to induce a greater regression of breast tumours in the mouse model compared to trastuzumab alone.
Small human trials using whole mushroom extracts have been performed too. In one, researchers observed that treatment with Trametes versicolor reduced the 5-year mortality of cancer patients up to 9%, particularly in case of breast, colorectal, and gastric cancer patients undergoing chemotherapy. In another study assessing breast cancer, the administration of freeze-dried mycelial powder of Trametes versicolor to 11 female cancer patients resulted in an enhancement of lymphocyte counts and NK cell functional activity, in addition to an upsurge in CD8(+) T cells and CD19(+) B cells, but not CD4(+) T cells. In another small study, patients with advanced hepatocellular carcinoma (HCC) with a liver malfunction, treated with Coriolus versicolor, had longer median OS compared with placebo, as well as longer median progression-free survival.
Other benefits
Other than having anti-cancer, immunomodulatory, anti-inflammatory, antioxidant and antibacterial properties, Trametes versicolor has also been shown to help reduce the effects of traumatic brain injury in mice. Mice treated with Hericium erinaceus (Lion’s Mane) and Trametes versicolor were able to reduce both the neuroinflammatory and oxidative processes which naturally occur after brain damage and this, in turn, reduced the mices’ risk of developing Parkinson’s disease.
Trametes versicolor extracts have also been shown to contain compounds baicalein and quercetin. Baicalein is a flavonoid with strong anti-inflammatory properties and has been shown to induce cell cycle arrest in cancer cells, and suppress cancer cell colony formation and migration. Quercetin is known to help release interferon, an antiviral signalling molecule, and this, in turn, may help with cancer reduction. Both these compounds have also been shown to inhibit acetylcholinesterase (AChE), the enzyme responsible for breaking down the neurotransmitter acetylcholine, and thus one study noted they may help with the treatment of cognitive impairment and dementia.
How to consume?
One way to ingest this mushroom is by making tea, however, another way it may be consumed is by fermenting it and making kombucha. One team of researchers did this and noted that the Turkey Tail kombucha could be beneficial in conditions like allergic reactions, asthma and atopic dermatitis. They also note that “kombucha mushroom polysaccharide extracts could contribute to the organism’s defence potential against external pathogens such as viruses”.
Fermented Turkey Tail mushrooms may also reduce oxidative stress, hyperglycemia, and hyperlipidemia in rats with type 2 diabetes mellitus. An anti-diabetic drink of sorts.
There is a protective effect of selenium against mercury toxicity and vice versa. Turkey Tail and other mushrooms like shiitake can accumulate selenium from the environment. And thus another way to consume Turkey Tail mushrooms is to cook them in fish soup!
Final remarks
It amazes me that this common little mushroom may prove to be life-changing and life-extending for some people, like Paul Stamets’ mother, who suffer from conditions like cancer. Though more studies are needed, Turkey Tail proves once again that the forest is in fact the ultimate pharmacy.
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