by
Eric Yarnell ND, RH(AHG)
An important aspect of prostate cancer is how it tricks, manipulates, and suppresses the immune system. is is central to the development and spread of prostate cancer, yet it is almost entirely ignored in conventional practice (Provenge® is one treatment that focuses on the immune system but it is little used, and almost always too late). Part of the reason for this is a lack of useful tools in conventional practice to help the immune system. But in naturopathic medicine, there are many ways to help counter prostate cancer’s harmful immune effects, to both prevent the disease from worsening and spreading and to cause it to regress in some cases.
Medicinal mushrooms are one of the most important tools in this regard. ey can help cancel the tricks prostate cancer plays, and get the immune system back to attacking the cancer instead of helping it.
How Prostate Cancer Hacks the Immune System, and How Mushrooms Help
Prostate cancer has to trick the immune system to survive. Otherwise the constant surveillance against cells with damaged DNA would lead to their destruction. Many types of white blood cells work together to find and destroy cancer cells. So prostate cancer has to work to manipulation, distract, and confuse all sorts of processes, not just one. Mutations that help prostate cancer do this are common and crucial to the cancer’s “success.” Mushrooms (and other natural therapies we won’t have time or room to discuss here) are important to countering these processes and restoring the various components of the immune system’s ability to control and kill prostate cancer.
Most prostate tumors have a shockingly large number of white blood cells in them, but they are either inactive or are actively telling other parts of the immune system to be inactive or to go away. Prostate cancer, to stay alive, has to have multiple mechanisms to shut off immune cells that are trying to attack it. Medicinal mushrooms aim to counter those mechanisms and get the immune cells actively fighting again. As a side note, this also means that medicinal mushrooms improve the ability of the immune system to fight off other cancers (including to prevent them from developing in the first place), help to reduce the risk of getting infections, and do all this without activating autoimmune disease (indeed, they also can help these at the same time they are fighting cancer). Mushrooms are not simply immune stimulators, they are immune modulators, meaning they turn some immune functions up (like those of anti-cancer white blood cells we want) while turning others down (like suppressive white blood cells that are excessively active, but without shutting them off completely).
One of the most surprising and unusual features of severe prostate cancer is that higher levels of what are known as cytotoxic T lymphocytes invading the cancer actually seems to help it. e only other cancer like this is kidney cancer. In all other cancers, these cells actively fight against the tumor and are helpful. Clearly prostate cancer is tricking these important cells into behaving badly.
Prostate cancer also tricks macrophages, types of white blood cells that act more like foot soldiers, into their so-called M2 form (vs. M1, as you might have guessed). e M2 macrophages show down inflammation locally. While we’ve often been inflammation is bad, the reality is inflammation is the word that means our immune system is working. While it can get out of control, it is also vital for fighting cancer locally. M2 macrophages help stop that, protecting prostate cancer cells from immune attack.
M2 macrophages plus what are known as T regulator lymphocytes (or Tregs) appear to be the key cells that prostate cancer tricks into working for the cancer, shutting off other white blood cells. Medicinal mushrooms work in part by knocking out these M2 and Tregs. ere are many other documented ways they help the immune system fight cancer again, and it starts to get pretty technical. I think you get the idea at this point, so let’s just move along into discussing how to use mushrooms.
Some evidence has found that regularly eating mushrooms helps prevent prostate cancer, though other studies have not been able to confirm this. e quantity of mushrooms consumed has generally been fairly low, making it difficult to be certain. e exact kinds of mushrooms eaten were also not generally quantified, and lumping all mushrooms together is not likely telling the whole story. But for now, it is likely that regularly consuming a range of mushrooms is healthy for many reasons.
e Whacky Wonder of Medicinal Mushrooms (and How to Choose a Good Product)
Mushrooms are not like plants. ey are in their own Kingdom, known as Fungi. ey do not have photosynthesis and so have to get their energy from somewhere else. is is mostly by either breaking down dead plants, or by stealing it from live ones.
Most mushrooms have two different phases of life that are very different. e one that is most familiar to us, because they are readily visible, are known as the fruiting bodies. ese are the obvious, above-ground parts of mushrooms, usually with flashy colors and interesting structures. e fruiting bodies make spores that spread and can create new mushrooms in other locations. None of the spores of medicinal mushrooms cause allergies or other harmful reactions; in fact, some of them are medicinal (such as those of reishi).
But most of the mass of mushrooms are hidden below the ground or inside rotting tree trunks. is form we don’t usually see. It is known as the mycelium. is mesh-like network of mushrooms is gigantic, but mostly invisible. e mycelium of most medicinal mushrooms is also medicinal, though in some cases the fruiting body is better. It is critical in all cases to know which part you are getting to get the right dose or, in some cases, to make sure you have the right form. If the product you are considering buying doesn’t say, it is clearly no good.
Some products also don’t really have much or even any mycelium. Some companies grow the mycelium on rice, and then just sell you the rice, claiming that the fungal mycelium has changed the rice in way that makes it medicinal. ere is very little evidence this approach makes an effective product. You are strongly discouraged from using such products.
Mushrooms also have very tough cell walls. Our own digestive tracts and gut bacteria can have a lot of trouble breaking these down. We can help them a lot by drying, freezing, and/or cooking the mushrooms to break up the cell walls. Fresh mushrooms are also fine and have some benefit when eaten, but they truly shine when they are processed (unlike most other foods).
All fruiting body products of mushrooms should be cooked before being powdered; this is pretty much how they’ve always been prepared and what studies show to be effective. e label might say they are hot-water extracted or decocted (boiled in water). Some are also then extracted with alcohol which is also helpful. But just ground up mushroom, be it fruiting body or mycelium, is not as effective.
Harvesting your own mushrooms in the wild is not something you should undertaken lightly. ere are some mushrooms that are extremely poisonous. You have to learn how to identify those and avoid them, and it’s tricky. Most of those discussed here probably aren’t growing where you live, if you’re in North America, or else aren’t that great to eat as food, so you’re better off using supplements from reputable companies or growing your own mushrooms at home. But if you are really serious, then start taking classes to learn to identify and harvest mushrooms safely.
Shiitake is a delicious mushroom native to Eastern Asia and now cultivated all over the world. e word shiitake is Japanese and is taken from the name of a tree (called shii) that the mushroom prefers to grow on, and take, meaning mushroom. e fruiting bodies are truly one of the best-tasting you can get. ey should be cooked to avoid a rare side effect that can occur after eating raw shiitake, in which an itchy rash appears all over the body and can last for days. I have never seen a patient get this from taking shiitake supplements or eating the cooked or dried mushrooms.
Shiitake is the most researched mushroom when it comes to prostate cancer. Like all mushrooms, complex polysaccharides (huge, branching chains of sugars) in shiitake are important to how they work. ey have unusual bonds known as beta-1,3 between their sugar units (human polysaccharides don’t have these bonds) that appear to be important in how they work. One of these shiitake polysaccharides in particular, known as lentinan, has been studied extensively. ere are many studies on oral use of products that are either just lentinan (usually in what is known as a superfine, dispersed form, which is not clearly available in North America) or shiitake extracts given orally in patients with other cancers showing they prolong survival without causing any adverse effects.
One large trial in Japan found that giving lentinan as an intravenous injection at a dose of 2 mg once per week, or 4 mg every other week, significantly extended the lifespan of patients with metastatic prostate cancer by an average of 13 months compared to those who didn’t get the injections. Injectable lentinan is not widely available in the USA, but check with your local naturopathic physician to find out if they have access. ere is some evidence from test-tube studies that shiitake polysaccharides may make docetaxel work better, so it should particularly be considered in patients undergoing this kind of chemotherapy.
e mycelium of shiitake is generally ok to use as medicine, but the one study we have on it in prostate cancer patients did not find it helpful. So I use only the fruiting body, until somebody can prove the mycelium is useful.
Trametes versicolor (Turkey Tail Mushroom)
is mushrooms grows all around the northern hemisphere on dead trees. If you squint, you could kind of imaging the fruiting body looks a little bit like a turkey’s tail. It is called yun zhi (“cloud mushroom”) in Chinese. It used to be called Coriolus versicolor, but mushroom experts figured out it was more closely related to another group and renamed it Trametes. You will see it is still called coriolus by some (though this is technically wrong). It is not particularly tasty, in part because it is very tough and chewy. So it is best taken in capsules or other extracts. e fruiting body and mycelium are both effective and useful, but all the research has been on hot-water extracts, so make sure you get one of those. A typical dose is 1000 mg twice per day with food.
ere are more human studies on turkey tail mushroom for people with cancer than any other mushroom by far. However, there is little about its effect on prostate cancer. I was a small part of a big clinical trial that was planned to look at turkey tail for people with advanced prostate cancer at Bastyr University, but we lost our funding as part of what was called the budget sequester that the US government implemented in 2014. As a result, we still don’t know for certain that turkey tail is helpful for people with prostate cancer. But the studies in patients with every other kind of solid tumor are so positive, it just has to be helpful. My clinical experience (and I give this mushroom to almost every prostate cancer patient so I have a lot of experience) is that it is helpful, in terms of people living longer and better. ere are no adverse effects from this mushroom.
ere is another related mushroom that is widely called Trametes robinophila in many studies. It is a mushroom used a lot in Chinese medicine, where it is called huai er. is has been renamed Vanderbylia robiniophila by mushroom scientists. ere is a lot of evidence it is also anticancer, just not very much specific to prostate cancer. erefore I don’t generally recommend this mushroom, given the stronger evidence we have for others.
is delicious mushroom is also native all around the Northern Hemisphere. Its Japanese name literally translates as “dancing mushroom.” It is also called hen-of-the-woods by some, referring to how tasty it is. No clinical studies of maitake in prostate cancer appear to have been done, but studies in test tubes show that it has potential to kill prostate cancer cells. It has been shown to have beneficial immune effects in patients with breast cancer.
e humble button mushroom, the most common mushroom sold in grocery stores in North American and Europe, has substantial ability to improve immune function. ey can be white or brown in color. Portobello and crimini mushrooms are different versions of this same species of mushroom. e vast majority (about 95%) of these mushrooms are grown in China. It has a very close relative known as Agaricus subrufrescens, formerly Agaricus blazei (sun mushroom, himematsutake). All of these shown promise against prostate cancer in the test tube. One small study showed only that sun mushroom was safe in patients with prostate and other cancers, except for one instance of allergy, and occasional mild nausea or loose stools. It remains to be be determined if they are effective in treating or preventing prostate cancer, but there is a good chance they will.
Conclusion
ere are many other types of medicinal mushrooms that are promising for preventing and treating prostate cancer, but the four kinds discussed here are some of the most widely-used and best studied. ese mushrooms are very safe and they have no known harmful drug interactions, thus it is ok to treat yourself with them as food or supplements. But if you want the maximum benefit, you are best off consulting with an experienced clinician who can help you choose the best forms and the best doses for your specific case.
Bibliography
(is is just a taste of some of the extensive research on medicinal mushrooms for prostate cancer.)
Adams LS, Phung S, Wu X, et al. (2008) "White button mushroom (Agaricus bisporus) exhibits antiproliferative and proapoptotic properties and inhibits prostate tumor growth in athymic mice" Nutr Cancer 60(6):744–56.
Deng G, Lin H, Seidman A, et al. (2009) "A phase I/II trial of a polysaccharide extract from Grifola frondosa (maitake mushroom) in breast cancer patients: immunological effects" J Cancer Res Clin Oncol 135(9):1215–21.
deVere White RW, Hackman RM, et al. (2002) “Effects of a mushroom mycelium extract on the treatment of prostate cancer” Urology 60(4):640–4.
A study showing shiitake mycelium ineffective in prostate cancer patients.
Eliza WL, Fai CK, Chung LP (2012) “Efficacy of yun zhi (Coriolus versicolor) on survival in cancer patients: Systematic review and meta-analysis” Recent Pat Inflamm Allergy Drug Discov 6(1):78–87.
Fullerton SA, Samadi AA, Tortorelis DG, et al. (2000) “Induction of apoptosis in human prostatic cancer cells with beta-glucan (maitake mushroom polysaccharide)” Mol Urol 4(1):7–13.
Jeong SC, Koyyalamudi SR, Jeong YT, et al. (2012) "Macrophage immunomodulating and antitumor activities of polysaccharides isolated from Agaricus bisporus white button mushrooms” J Med Food 15(1):58–65.
Kwon JTW, Bryant RJ, Parkes EE (2021) “e tumor microenvironment and immune responses in prostate cancer patients” Endocr Relat Cancer 28(8):T95–T107.
Technical discussion of how prostate cancer throws off the immune system.
Full text available online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8345898/.
Oba K, Kobayashi M, Matsui T, et al. (2009) “Individual patient based meta-analysis of lentinan for unresectable/recurrent gastric cancer” Anticancer Res 29(7):2739–45.
Ohno S, Sumiyoshi Y, Hashine K, et al. (2011) "Phase I clinical study of the dietary supplement, Agaricus blazei Murill, in cancer patients in remission" Evid Based Complement Alternat Med 2011:192381.
Pan J, Yang C, Jiang Z, Huang J (2019) “Trametes robiniophila Murr: A traditional Chinese medicine with potent anti-tumor effects” Cancer Manag Res 11:1541–9. https://www.ncbi.nlm.nih.gov/pmc/ articles/PMC6389013/
Schuurman AG, Goldbohm RA, Dorant E, van den Brandt PA (1998) "Vegetable and fruit consumption and prostate cancer risk: A cohort study in e Netherlands" Cancer Epidemiol Biomarkers Prev 7(8):673–80.
Tari K, Satake I, Nakagomi K, et al. (1994) “Effect of lentinan for advanced prostate carcinoma” Hinyokika Kiyo 40(2):119-–3 [in Japanese].
Wang X, Ha D, Mori H, Chen S (2021) "White button mushroom (Agaricus bisporus) disrupts androgen receptor signaling in human prostate cancer cells and patient-derived xenograft” J Nutr Biochem 89:108580.
Yu CH, Kan SF, Shu CH, et al. (2009) “Inhibitory mechanisms of Agaricus blazei Murill on the growth of prostate cancer in vitro and in vivo” J Nutr Biochem 20(10):753–64.
Zhang S, Sugawara Y, Chen S, et al. (2020) “Mushroom consumption and incident risk of prostate cancer in Japan: A pooled analysis of the Miyagi Cohort Study and the Ohsaki Cohort Study” Int J Cancer 146(10):2712–20.
Zhang W, Tao N, Bai L (2023) “Polysaccharides from Lentinus edodes prevent acquired drug resistance to docetaxel in prostate cancer cells by decreasing the TGF-β1 secretion of cancerassociated fibroblasts” J Nat Med 77(4):817–28
Zhang YY, Campbell BK, Stylli SS, et al. (2022) “e prostate cancer immune microenvironment, biomarkers and therapeutic intervention” Uro 2(2):74–92. Another technical paper on how prostate cancer suppresses the immune system. Full text available online at https://www.mdpi.com/2673-4397/2/2/10.
Zhong L, Yan P, Lam WC, et al. (2019) “Coriolus versicolor and Ganoderma lucidum related natural products as an adjunct therapy for cancers: A systematic review and meta-analysis of randomized controlled trials” Front Pharmacol 10:703.