Let me introduce you to one of the most revered of all medicinal mushrooms: Reishi! Reishi is the most popular common name used today, being the Japanese pronunciation of the traditional Chinese term líng-zhī, which is a difficult term to translate. Líng means something like spiritual, miraculous, sacred, or divine. Zhī has no equivalent in the West and refers to a variety of what are described as "supermundane substances": excrescences. You might think of these like the modern idea of superfoods but with a mystical quality, as they are thought to be substances that bestow immortality. So Reishi has diverse translations like “plant of immortality”, “herb of spiritual potency”, or simply “spirit fungus”.
Documented use goes back over 2,000 years in ancient China, however there are many medicinal species within Ganoderma, and positive identification from ancient description is rarely obvious. Traditional texts refer to multiple types of Reishi, differentiated by colour (i.e. red reishi, purple reishi, and more besides). Red Reishi has a non-edible, hard and bitter tasting polypore fruit body that extends like a shiny fan from a stalk-like structure. It is currently filed taxonomically as G. lucidum, (lucidum in Latin means bright and shiny), however historically many Ganoderma spp. have been lumped together under this name. Read more on this in the final section of this blog post.
Traditional Chinese Medicine lists Reishi as a tonic and Qi restorative that promotes general health, long life, and youthfulness. It is utilised to strengthen the heart, and treat palpitation, shortness of breath, asthma, cough, dizziness, and insomnia, as well as to ease the mind . As we are about to discover, Reishi does indeed appear to have a soothing effect upon the nervous, cardiovascular, and immune systems.
Reishi has particularly broad medicinal potential which makes sense as we uncover the vast collection of bioactive constituents it contains. Aside from an array of fungal polysaccharides with their various immunoregulatory actions, Reishi also contains many triterpenoids and related chemicals. More than one hundred triterpenoids have been reported from Reishi, however the content is mostly represented by ganoderic acids (A & B) and lucidenic acids . The triterpenoid content is known to vary between parts of the fungus , and it loses its chemical diversity in cultivated and commercial samples compared to wild specimens .
A general review from this year summarises the main biological effects of Reishi as :
Immunomodulatory & anti-inflammatory
Anti-cancer (including cytotoxic, antimetastatic, and other immunoregulatory activities), with value as adjuvant to conventional cancer therapy
Antioxidant and organoprotective, with particular affinity for liver and brain
Anti-diabetic, anti-hypertensive, anti-obesity
As with all fungi, the polysaccharides from Reishi appear to offer extensive immunological effects, promoting the innate, humoral and cellular aspects of immunity. We see significant enhancement of immune function in healthy animals, as well as its restoration to health in models of aging and stress, or with immunosuppressive drug use. Reishi seems to benefit autoimmune disorders and can assist with depressing the allergic response as well. The preclinical research for Reishi’s immune mechanisms is extensive but, surprisingly, clinical trials are still lacking .
Reishi has stirred interest as an antitumor agent thanks to its powerful immunological effects. There have been clinical trials where we see positive results with Reishi as an adjuvant to chemo- or radiotherapy. Observations include reduced suppression of blood cells (stem cell protective), attenuation of gastrointestinal side effects (eg. anorexia, nausea, diarrhoea), enhanced immunological defences against infection and cancer, and improved physical fitness and quality of life. Furthermore, there is in vitro evidence that Reishi triterpenoids and/or other non-polysaccharide components have a direct cytotoxic effect on tumour cells. Even though so much immunological research in fungi is focused on the polysaccharides, here is an example of why we want a whole ‘Galenical’ extract to capture the full spectrum of activity .
An interesting randomized, double-blind, placebo-controlled trial enrolled 167 asymptomatic 3-5 year-old children to study the effect of 350 mg Reishi β-glucans (from fermented mycelium) on various immune system parameters. Yoghurt enriched with the β-glucans was taken daily for five days (Monday to Friday) each week, for 12 weeks (placebo unenriched plain yoghurt). There was a significant increase in peripheral blood lymphocytes, CD3+, CD4+, CD8+ T cells. These cells are critical in the defense against infectious threats in asymptomatic children of this age group .
One of the other fundamental mechanisms behind much of what Reishi does for us is based on it dampening states of oxidative stress which lead to chronic inflammation and tissue damage. In the cardiovascular arena, we have single-blinded trial evidence of antioxidant-based protective mechanisms in a population at high risk of atherosclerosis or with stable angina . Three months’ intake of a specific polysaccharide peptide component from Reishi delivered significant anti-atherosclerotic protection with improved measures of oxidative stress. In a double-blind study, people with hypertension and/or hypercholesterolaemia experienced anti-diabetic effects and improved markers associated with dyslipidaemia . Such metabolic-regulatory behaviour often goes hand-in-hand with antioxidant and hepatoprotective actions.
Indeed, Reishi is understood to have a particular affinity for liver health, with supportive pre-clinical data tracing back to Chinese animal studies in 1974! Today we have elucidated a variety of mechanisms at play that contribute to Reishi’s hepatoprotective effect in different liver disease states (from hepatocellular carcinoma to non-alcoholic and alcoholic fatty liver, and more) . In a primarily healthy, middle aged cohort with mild liver dysfunction, six months of Reishi intake resulted in significant improvements to antioxidant protection as measured with liver and antioxidant markers. Ultrasonic examination of these people found that fatty liver status had been reduced to normal healthy tissue .
In the nervous system, we also see Reishi shine. The Chinese tradition has utilized Reishi as a sedative for insomnia and anxiety. Researchers have suggested the involvement of multiple targets toward this effect, including immune cytokines, as well as the benzodiazepine receptor and inhibition of GABA reuptake. Mice demonstrate reduced sleep latency and prolonged sleep duration (without affecting REM sleep) with Reishi. This contrasts with benzodiazepines which reduce REM and deep sleep [11,12]. The antioxidant capacity of Reishi contributes to broad neuroprotective effects. These appear to be effective in neurodegenerative diseases and brain injury, including for Alzheimer’s and Parkinson’s diseases, spinal cord injury, stroke, epilepsy, and depression. [11,13,14].
Women with fibromyalgia experienced significantly improved aerobic endurance, flexibility and velocity with 6 g of Reishi daily for 6 weeks. This was compared with Carob (renowned antioxidant herb/food) which had no significant effects, indicating other mechanisms working here . Could one of those mechanisms be to do with hormonal modulation? Testosterone and progesterone dysregulation has been linked to fibromyalgia, particularly the occurrence of pain . It would be interesting if the women in the previous study were also reporting on their fibromyalgia-related pain. We have evidence of one constituent, ganoderol B, interacting with the androgen receptor and exhibiting 5α-reductase inhibitory activity. This androgen-modulation could support the health of the prostate, and potentially offer some protection against prostate cancer and benign prostate hyperplasia . So it is not surprising that in a study of men with lower urinary tract symptoms (LUTS), 6 mg of an ethanolic extract of Reishi significantly improves the International Prostate Symptom Score results, indicating better prostate health [18,19].
Safety, Quality and Dosing
With the taxonomy of the Ganoderma genus in flux, there can be confusion with accurate identification. G. lucidum is considered the standard medicinal species today and has received the most attention for research.
As is my general rule for medicinal fungi, I recommend utilizing the fruit body over the mycelium for the best results with Reishi (at least until more research is available supporting this non-traditional use of mycelium). Another of the fungal parts that is starting to appear on the market is the spores, especially for Reishi. Being the reproductive cells, they are considered by some to hold a more potent, condensed essence of Reishi medicine. With comparatively scant research on the biological activity of the spores and their safety, I suggest being cautious with their application for now.
As Reishi is non-edible, it is best taken as a decoction or dry extract. Traditionally hot water was used as the solvent however combining ethanol and water allows for a more complete ‘full-spectrum’ extraction and is my preference.
Reishi has an excellent safety profile, with only a very rare incidence of allergy possible (probably no more than any other fungal species). Caution is also advised if using Reishi with concomitant anticoagulant or antiplatelet medication [13,20]. I recommend Reishi dry fruit body taken at 2-6 g daily (divided into two even doses is best).
If you would like a more in-depth and clinically-focussed take on this excellent medicinal fungus, see my Reishi Monograph [COMING SOON!].
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