Written by Martin Powell
Medicinal mushrooms represent a fascinating and hitherto neglected category of nature’s pharmacopoeia. Neither plants nor animals but sharing characteristics of both mushrooms have much to offer for a number of disease categories including:
- Cancer
- Auto-immune conditions
- Neurodegenerative conditions
- Chronic viral infections
Medicinal mushrooms and their actions
Key to their ability to assist with many of these areas is the immune-modulating activity of the beta-glucans, proteoglycans and related polysaccharides which are important structural components of the mushroom cell wall.
Receptors with specific binding sites for such polysaccharides are found on many of the cells that make up the immune system and they have also been shown to have a prebiotic effect on the gut flora, promoting the growth of beneficial bacteria, enhancing intestinal barrier integrity, increasing levels of short-chain fatty acids and enzyme activity.
Given their positive immunological and prebiotic activity it is perhaps not surprising that increased mushroom consumption has been correlated with reduction in the risk of developing cancer in a number of large-scale epidemiological studies including three looking specifically at breast cancer risk and one at prostate cancer with regular mushroom consumption linked to a lower cancer risk in all cases, especially in older age groups.
As if that was not enough reason to reconsider mushrooms as an important food category for health maintenance, especially as we get older, mushrooms also produce an array of secondary metabolites with diverse health benefits.
Of these one of the most common is lovastatin, which like most other such secondary metabolites is produced by mushrooms and other fungi for its anti-microbial properties, in this case its anti-fungal action.
Other such compounds include:
- Triterpenes from several species including Reishi with actions including anti-inflammatory, sedative, anti-allergic, anti-hypertensive
- Diterpenes including erinacines and hericenones from Hericium species with NGF-promoting properties
- Nuceoside-derivatives such as Cordycepin with anti-viral, anti-inflammatory properties in Cordyceps species
- Ergothioneine, an antioxidant amino acid found in porcini and oyster mushrooms with anti-ageing properties
- Cordycepin and Long-Covid: Cordycepin (3’-deoxyadenosine) one of the key active molecules found in Cordyceps species, especially Cordyceps militaris is a close relative of Didanosine (2’,3’-dideoxyadenosine – used as part of HAART treatment for HIV/AIDS under the brand name Videx) and like Didanosine exhibits strong anti-viral activity. In addition it is a potent anti-inflammatory and contributes to Cordyceps’ traditional therapeutic use to increase energy and support the Lungs and Kidneys, including promoting steroid hormone production. With recent studies also pointing to protective properties for both cordycepin and Cordyceps militaris against lung injury from acute inflammation it is rapidly emerging as a promising candidate to help address the symptoms associated with Long Covid.
Mushrooms are also the only non-animal food to contain significant quantities of vitamin D with ergosterol in the cell wall converted to vitamin D2 on UV-exposure.
Traditional views on mushrooms as medicine
While awareness of mushrooms’ health benefits is relatively recent in countries such as the UK and USA, in others, especially in East Asia it has long been part of herbal traditions with the earliest Chinese materia medica, the Shen Nong Ben Cao, dating to around 200AD, including several still in use today:
• Ling Zhi (Ganoderma lucidum – Reishi)
• Fu Ling (Poria cocos)
• Zhu Ling (Polyporus umbellatus)
All of these are classified in the ‘Superior’ category of herbs, herbs which are considered safe to take for long periods of time without side effects and of which it is said that prolonged use will ‘lighten the body and confer longevity’. Indeed, G. lucidum has long been thought to be the plant Chi mentioned in a number of Taoist texts as a plant that brings happiness and immortality, although it is now believed that Chi and its classical categorisation according to six colours actually refers to a number of different species.
Over time the incorporation of mushrooms into the materia medica expanded so that in Li Shi Zhen’s authoritative work, the Ben Cao Gang Mu (1578), 21 mushrooms are listed as having medicinal properties and the reverence with which medicinal mushrooms, especially Reishi are held in Chinese culture is attested to by their extensive depiction in paintings, carvings and embroidery.
A modern perspective on medicinal mushrooms
In the last few years awareness of mushrooms’ health benefits and the commercial possibilities they offer has seen interest in them take off in Europe and North America with a proliferation of new mushroom-based products and extended coverage in mainstream media such as the BBC and National Geographic magazine.
Unfortunately, even more so than with other herbs this increased interest has been accompanied by a proliferation of conflicting and competing claims and together with an opaque supply chain has resulted in a confusing landscape for those wishing to explore this area.
In order to address the need for education around medicinal mushrooms Mycology Press recently launched The Mushroom magazine and is currently setting up the Medicinal Mushroom Information Centre.
References
Mycotherapy of cancer: an update on cytotoxic and antitumor activities of mushrooms, bioactive principles and molecular mechanisms of their action.
Popović V et al. Curr Top Med Chem. 2013;13(21):2791-806.
A Critical Review on Health Promoting Benefits of Edible Mushrooms through Gut Microbiota.
Jayachandran M, Xiao J, Xu B. Int J Mol Sci. 2017 Sep 8;18(9):1934.
A Review of Mushrooms as a Potential Source of Dietary Vitamin D. Cardwell G, Bornman JF, James AP, Black LJ. Nutrients. 2018 Oct 13;10(10):1498.
Cordycepin: a bioactive metabolite of Cordyceps militaris and polyadenylation inhibitor with therapeutic potential against COVID-19.
Akalesh Kumar Verma. J Biomol Struct Dyn. 2020 Nov 23;1-8.
