What is Reishi Mushroom?
Almost no medicinal mushroom holds equal or greater prestige than the legendary Reishi Mushroom. It’s an emblematic species in the world of herbal medicine and has a growing body of scientific evidence backing its use.
In Chinese Folklore it is known as Lingzhi (the name Reishi actually originates from Japan) and has been used for centuries, mystified as “The Mushroom of Immortality”. While this title is a tad glorified, there’s likely a good basis for this esteem. After all, it’s best known to help prevent/regulate many different illnesses and diseases that could shorten one’s life.
This includes supporting immune function and improving health conditions such as diabetes, heart disease, and cancers. Other potential uses include helping against depression/anxiety, improving sleep, and generally helping your body respond to stress.
Scientific evidence and deep tradition both support the use of these mushrooms, but keeping a holistic understanding of our health are important. Medicines like Reishi should be employed with healthy lifestyles and diets for effective treatments of any illness.
Taxonomic Clarification Of Reishi Mushrooms
Many of us learned Ganoderma lucidum as the scientific name for the powerful Reishi mushroom. You may have seen the name on commercial products, in scientific articles, and even told it by many well-informed mushroom enthusiasts. Long story short, this name has often been misapplied to a diverse set of closely related species. While they may look the same to the untrained eye, they actually have been shown to have unique medicinal properties. This includes the misapplication of the name Ganoderma lucidum to the Asian varieties used in Traditional Chinese Medicine.
Ganoderma lucidum explained
Ganoderma lucidum is a mushroom originally described in Europe in 1881. It is a relative to the traditional Lingzhi mushrooms used in China. Due to the cryptic nature of these species, the name Ganoderma lucidum has been misapplied to not only the “Lingzhi” mushroom but to countless other similar-looking species.
Unfortunately for many researchers, foragers, medicine makers, and unaware mushroom enthusiasts, this causes confusion. Considering this is of particular importance because different species have distinct chemical profiles and medicinal properties. The local “Reishi” you’ve been harvesting in your backwoods, or purchasing in tinctures, may not have the same effects claimed in Traditional Chinese Medicine or that have been backed by science!
If it wasn’t confusing enough, researchers are still in “heated debate” on the name to use for the traditionally cultivated Lingzhi mushroom. The names proposed for the traditional Lingzhi mushroom are either G. lingzhi or G. sichuanense (Yao 2020, Dai 2018), although many individuals continue using G. lucidum despite the distinctions made by taxonomic experts.
In most cases, research conducted in China and Asia likely used raw materials of the true “Lingzhi” variety of Ganoderma. Outside of these regions scientists may have used the European, Ganoderma lucidum or another close relative. Unfortunately, these taxonomic distinctions really cause some issues when it comes to understanding the distinct medicinal properties between species.
While these mushrooms may have unique chemical profiles, they are closely related. All of these mushrooms belong to the Subgenus Ganoderma within the genus Ganoderma. They are also commonly referred to as the “Ganoderma lucidum complex” or “Laccate Ganoderma”. Since this is an area of developing research we will be using the name “Reishi ” ambiguously when referring to this group of species.
While this information may seem shocking to some, this is very common in the taxonomy of mushroom-forming fungi. The European names of countless species have been misapplied across the world to their closely related counterparts due to the similarities in morphology and lack of research.
Selected Species In The Ganoderma lucidum complex
- Ganoderma tsugae
- Ganoderma sessile
- Ganoderma curtisii
- Ganoderma oregonense
- Ganoderma lucidum
- Ganoderma polychromum
- Ganoderma zonatum
- Ganoderma resinaceum
- Ganoderma tropicum
Natural History and Ecology of Reishi
Reishi mushrooms are a type of polypore or “shelf fungus” that grow from tree trunks and branches of hardwood trees. In some cases, some varieties of Reishi will occur on softwoods. While they often just rot dead wood and may occur on living trees with little problems, they are also often considered pathogenic and may harm trees. Large trees infected with Reishi near homes should be inspected by an arborist and considered for removal.
Ecologically, these mushrooms play important roles in the nutrient cycling process. This process involves the decomposition of complex organic materials such as wood, into simpler plant-available compounds. Through this process, soils become enriched with nutrients and organic matter, a central part of ecological succession.
Aside from its role in nutrient cycling, Reishi mycelium and fruiting bodies are also important food/habitats for many species. Certain forms of insect detritivores consume mycelium and are regularly observed from trunks rotting with Ganoderma. Some insects also use the Ganoderma fruiting bodies as food or habitat for breeding.
Reishi mycelium can live for years within a decomposing tree trunk but the fruiting bodies are short-lived. In temperate climates, they may have very pronounced seasons in which they fruit while in tropical climates they occur year-round. The fruiting bodies may only last 1-2 months before they begin to turn soft and decompose. This is in contrast to more distant relatives within the genus such as the “Artist Conk” or Ganoderma applanatum, these form long-lived fruiting bodies that grow for years.
What Do Reishi Mushrooms Look Like?
They are usually red to brown and may be coated with their dusty brown spores. Brushing away this dust from its upper surface will reveal a unique and shiny surface, for which it’s given the common name “Varnished Conk”. The term “Laccate Ganoderma” is also commonly referenced in literature to refer to the ambiguous group of varnished conks.
Its shape can greatly vary on variety/environment but they are usually fan-shaped and can be as small as 5 cm or as large as 100 cm! Certain environmental conditions and genetic varieties will produce long stems.
The underside of the mushrooms is white when mature and eventually begins turning brown with age. Immature specimens have a white outer margin which is where new growth is occurring. Once this white outer margin is gone, the mushroom is mature, and the best point to harvest!
Where Do Reishi Mushrooms Grow?
Reishi mushrooms occur around the world in both temperate and tropical climates. Their distribution is largely limited to forested ecosystems with medium to large trees. If you have forests near you, there is likely at least one variety of Reishi found there!
The traditional Lingzhi variety is only thought to occur in China and Eastern Asia. Genetic analysis of a wide variety of specimens suggests that the true European Ganoderma lucidum only occurs in Europe and small parts of Asia, although it may have escaped from cultivation in other parts of the world.
Medicinal Properties Of Reishi
The acclaimed medicinal properties of Reishi mushrooms are vast. They’re most known for their ability to improve immune function and for their use in cancer treatments. They also have strong anti-inflammatory effects, are high in antioxidants, and could help with various chronic diseases. This includes high blood pressure, heart disease, diabetes, and even emotional disorders.
Lastly, Reishi is revered as one of the most treasured adaptogenic herbs. Adaptogens are herbs that work to help regulate and manage various forms of stress in the body, including physical, emotional, and environmental stresses. They do this by helping regulate and balance your body’s natural stress response system.
Yet, as is the case with many traditional medicines, there is only limited scientific research showing the effectiveness of all the claims. While some studies have had mixed results, there is in general a promising outlook on some of the claims made about Reishi mushrooms.
Lastly, the research on Reishi mushrooms is a bit confusing simply due to taxonomic errors made in the literature. These errors continue to be made in contemporary literature and are a major source of uncertainty in these studies. While we can assume that most studies done in China and East Asia were done with the Traditional Lingzhi varieties (even if the name Ganoderma lucidum is used), the source mushrooms used in many European and North American studies remain ambiguous unless otherwise mentioned.
Active Compounds In Reishi Mushrooms
The mushrooms and mycelium of Reishi mushrooms are known to contain about 400 different bioactive compounds that include polysaccharides, triterpenoids, nucleotides, sterols, steroids, fatty acids, proteins, and other trace elements (Zeng, 2018). Amongst these, unique polysaccharides and triterpenoids from Reishi have been shown to be the most biologically active.
Polysaccharides are one of the major components of Reishi mushrooms and form a large part of the fungal biomass. Over 200 different polysaccharides have been isolated from the mushrooms and mycelium, with many new novel ones still being discovered. In particular, a special type of polysaccharide known as beta-glucans has been shown to be the most promising in terms of medicinal properties.
Beta-glucans are found in all fungi as they form a major component of the cellular structures. These same types of polysaccharides are the main active ingredients in many medicinal mushrooms, albeit each species contains different forms of beta-glucans. In particular, these compounds have been shown to have antioxidant, antitumor, immuno-regulatory, anticancer, and hypoglycaemic activities.
Triterpenes are the water-insoluble part of the mushrooms and possess many unique properties. Most notably they are known to help with various forms of cancer. Triterpenes are considered particularly bitter, which may be a good indicator of the triterpene content of a fruiting body.
Research Highlights
Improving Immune Function
- Researchers in Colombia performed a double-blinded, placebo-controlled clinical study to observe the immunomodulatory activity of children aged 3 to 5. It showed that β-glucans from G. lucidum increase the frequency of immune system cells in the peripheral blood. These are cells important for defense against infectious threats in asymptomatic children. (Urrego, 2018)
- Reishi may help modulate white blood cells under conditions of intense physical activity and hypoxia. (Zhang, 2009)
Helping In Cancer Treatment
- Reishi may help patients with colorectal cancer by increasing the number of white blood cells. (Chen, 2006)
- Both water-soluble and water-insoluble components of Reishi mushrooms have been shown to help inhibit and regulate the growth of cancer cells from various cell lines in culture. (Chung, 2001)
- Various triterpenes from Ganoderma were shown to have cytotoxic effects on Meth-A and LLC tumor cell lines. (Min, 2000)
- Two species of Ganoderma, G. sinense and G. lucidum, were shown to have antitumoral proliferation effects. While their biochemical composition greatly differs they both were effective via the apoptosis pathway and the cell cycle arrest effect. (Liu, 2009)
- Extracts from Reishi mushroom spores were shown to induce apoptosis of breast cancer cells in vitro and in vivo. They did this by activating caspase-3 and caspase-9 proteases. (Jiao, 2020)
- Water-soluble polysaccharides isolated from Ganoderma sp. were shown to inhibit tumor growth and prolong survival of mice with lung cancer. (Hsu, 2020)
Could Help With Depression
- Ethanol extracts of Reishi mushrooms showed antidepressant-like activity in Mice. (Muhammad, 2017)
- Water-soluble extracts o