Mushroom’s phytochemicals, such as beta-glucan, enhance the activity of several different types of immune cells including natural killer cells, which attack and destroy virus-infected and cancerous cells.
The immune-enhancing actions of mushrooms are thought to help the body to more effectively attack microbial invaders and developing tumors.1-3 According to a study on healthy volunteers who ate white button mushrooms daily, mushrooms may also help to prevent infections by enhancing salivary immunoglobulin A production; immunoglobulins are antibodies secreted by mucosal surfaces (such as the digestive system and respiratory tract) to protect against infection.4 Similar results were found for shiitake mushrooms in healthy people: after 4 weeks of eating 5-10 g dried shiitake mushrooms daily, there was an increase in salivary immunoglobulin A.5 The immune system protects us against infection and also cancer. Many clinical trials have investigated concentrated mushroom polysaccharide extracts as an adjunct treatment for improving immune function in patients with cancer.6-9
One notable study found frequent consumption of mushrooms (10 g, or approximately one button mushroom per day) has been linked to a 64 percent decrease in the risk of breast cancer.10 A meta-analysis estimated that mushroom intake results in a 4-6 percent risk reduction per gram of mushrooms eaten per day.11 Another meta-analysis of 17 observational studies concluded that high mushroom intake was linked to 34% lower risk of any cancer and 35% lower risk of breast cancer compared to low mushroom intake.12 Mushrooms are thought to protect against breast cancer particularly because they inhibit an enzyme called aromatase, which produces estrogen. Several varieties of mushrooms, especially the commonly eaten white button and portobello mushrooms, have strong anti-aromatase activity.13
Consumption of mushrooms does not only protect against breast cancer. Some mushrooms contain specialized lectins (such as ABL in common white, cremini, and portobello mushrooms) that recognize cancer cells, and prevent the cells from growing and dividing.14,15 Mushroom beta-glucans interact with immune cells, promoting an anti-tumor immune response.1,2 In addition, white, cremini, portobello, oyster, maitake, and reishi mushrooms each contain bioactive compounds with the potential for anti-cancer activity. These mushroom phytochemicals have anti-angiogenic, anti-proliferative, and other anti-cancer effects, which have been studied in relation to stomach, colorectal, breast, and prostate cancers.16-25
Mushrooms are the richest dietary source of the specialized antioxidant ergothioneine; all mushrooms contain some ergothioneine, but oyster mushrooms contain the most. Other significant dietary sources of ergothioneine include oat bran, black turtle beans, and red kidney beans.26-28 Many human cells have a transporter protein whose main known function is to bring ergothioneine into the cell.29
Studies on dietary factors and cognitive health in older adults, particularly in Asia, have found that greater mushroom consumption or ergothioneine levels in the blood were associated with better brain health.30-32
Ergothioneine is found in almost all human cell and tissue types and tends to accumulate in tissues exposed to high levels of oxidative stress.27,28 The brain is one of those tissues; there are high levels of oxidation products because of its high metabolic activity, and the mitochondria in particular is the site of highest oxidative stress. Mitochondrial DNA does not have the same robust protection and repair mechanisms as regular DNA, so mitochondrial DNA is more susceptible to oxidative damage. Oxidative damage to mitochondria is thought to be a major contributor to neurodegenerative diseases, such as Alzheimer’s Disease and Parkinson’s Disease.27 Ergothioneine’s protection of the mitochondria may protect the brain from oxidative damage, helping to prevent neurodegenerative diseases.
Mushrooms should only be eaten cooked. Several raw culinary mushrooms contain small amounts of a potentially carcinogenic substance called agaritine, and cooking mushrooms significantly reduces agaritine content.33-35 Mushrooms add unique flavors and textures to vegetable dishes, and are delicious paired with fresh herbs. Combining mushrooms with the onion family, green and cruciferous vegetables, and beans, creates delicious, healthful, and powerfully protective meals.
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Akramiene D, Kondrotas A, Didziapetriene J, Kevelaitis E. Effects of beta-glucans on the immune system. Medicina (Kaunas) 2007, 43:597-606.
Jeong SC, Koyyalamudi SR, Pang G. Dietary intake of Agaricus bisporus white button mushroom accelerates salivary immunoglobulin A secretion in healthy volunteers. Nutrition 2012, 28:527-531.
Dai X, Stanilka JM, Rowe CA, Esteves EA, Nieves C, Jr., Spaiser SJ, Christman MC, Langkamp-Henken B, Percival SS. Consuming Lentinula edodes (Shiitake) Mushrooms Daily Improves Human Immunity: A Randomized Dietary Intervention in Healthy Young Adults. J Am Coll Nutr 2015, 34:478-487.
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Jin X, Ruiz Beguerie J, Sze DM, Chan GC. Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database Syst Rev 2016, 4:CD007731.
Zhang Y, Zhang M, Jiang Y, Li X, He Y, Zeng P, Guo Z, Chang Y, Luo H, Liu Y, et al. Lentinan as an immunotherapeutic for treating lung cancer: a review of 12 years clinical studies in China. J Cancer Res Clin Oncol 2018, 144:2177-2186.
Ina K, Kataoka T, Ando T. The use of lentinan for treating gastric cancer. Anticancer Agents Med Chem 2013, 13:681-688.
Zhang M, Huang J, Xie X, Holman CD. Dietary intakes of mushrooms and green tea combine to reduce the risk of breast cancer in Chinese women. Int J Cancer 2009, 124:1404-1408.
Li J, Zou L, Chen W, Zhu B, Shen N, Ke J, Lou J, Song R, Zhong R, Miao X. Dietary mushroom intake may reduce the risk of breast cancer: evidence from a meta-analysis of observational studies. PLoS One 2014, 9:e93437.
Ba DM, Ssentongo P, Beelman RB, et al. Higher Mushroom Consumption Is Associated with Lower Risk of Cancer: A Systematic Review and Meta-Analysis of Observational Studies. Adv Nutr 2021.
Grube BJ, Eng ET, Kao YC, Kwon A, Chen S. White button mushroom phytochemicals inhibit aromatase activity and breast cancer cell proliferation. J Nutr 2001, 131:3288-3293.
Yu L, Fernig DG, Smith JA, Milton JD, Rhodes JM. Reversible inhibition of proliferation of epithelial cell lines by Agaricus bisporus (edible mushroom) lectin. Cancer research 1993, 53:4627-4632.
Carrizo ME, Capaldi S, Perduca M, Irazoqui FJ, Nores GA, Monaco HL. The antineoplastic lectin of the common edible mushroom (Agaricus bisporus) has two binding sites, each specific for a different configuration at a single epimeric hydroxyl. The Journal of biological chemistry 2005, 280:10614-10623.
Hara M, Hanaoka T, Kobayashi M, Otani T, Adachi HY, Montani A, Natsukawa S, Shaura K, Koizumi Y, Kasuga Y, et al. Cruciferous vegetables, mushrooms, and gastrointestinal cancer risks in a multicenter, hospital-based case-control study in Japan. Nutr Cancer 2003, 46:138-147.
Zhang CX, Ho SC, Chen YM, Fu JH, Cheng SZ, Lin FY. Greater vegetable and fruit intake is associated with a lower risk of breast cancer among Chinese women. Int J Cancer 2009, 125:181-188.
Martin KR, Brophy SK. Commonly consumed and specialty dietary mushrooms reduce cellular proliferation in MCF-7 human breast cancer cells. Experimental Biology and Medicine 2010, 235:1306-1314.
Fang N, Li Q, Yu S, Zhang J, He L, Ronis MJ, Badger TM. Inhibition of growth and induction of apoptosis in human cancer cell lines by an ethyl acetate fraction from shiitake mushrooms. Journal of alternative and complementary medicine 2006, 12:125-132.
Ng ML, Yap AT. Inhibition of human colon carcinoma development by lentinan from shiitake mushrooms (Lentinus edodes). Journal of alternative and complementary medicine 2002, 8:581-589.
Adams LS, Phung S, Wu X, Ki L, Chen S. White button mushroom (Agaricus bisporus) exhibits antiproliferative and proapoptotic properties and inhibits prostate tumor growth in athymic mice. Nutrition and Cancer 2008, 60:744-756.
Lakshmi B, Ajith TA, Sheena N, Gunapalan N, Janardhanan KK. Antiperoxidative, anti-inflammatory, and antimutagenic activities of ethanol extract of the mycelium of Ganoderma lucidum occurring in South India. Teratogenesis, carcinogenesis, and mutagenesis 2003, Suppl 1:85-97.
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Zhang S, Tomata Y, Sugiyama K, Sugawara Y, Tsuji I. Mushroom Consumption and Incident Dementia in Elderly Japanese: The Ohsaki Cohort 2006 Study. J Am Geriatr Soc 2017, 65:1462-1469.
Feng L, Cheah IK, Ng MM, Li J, Chan SM, Lim SL, Mahendran R, Kua EH, Halliwell B. The Association between Mushroom Consumption and Mild Cognitive Impairment: A Community-Based Cross-Sectional Study in Singapore. J Alzheimers Dis 2019, 68:197-203.
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