What are medicinal mushrooms (or “healing mushrooms”)?

Medicinal mushrooms are those types of mushrooms that are believed to have medicinal properties and that have been well researched scientifically. Of the approximately 1.5 million species of mushrooms that we know of, there are about a dozen mushrooms that currently fall into this category.

In traditional Chinese medicine (TCM), medicinal mushrooms have been used for over 5000 years. But even in conventional medicine in Japan and China, some medicinal mushrooms have been an integral part of treatment for almost 40 years, especially in cancer therapy.

What substances are contained in medicinal mushrooms?

All medicinal mushrooms contain numerous trace elements, minerals (e.g. potassium, which lowers blood pressure) and fiber (especially beta-glucans).

Beta-glucans are responsible for the positive effect on the immune system (see the following section), but also have an antibacterial effect, are antioxidant in many parts of the body and can close holes like “glue”, which is relevant, for example, in the context of leaky gut or other diseases of the gastrointestinal tract, and which will be discussed in more detail below.

Also of great importance are the triterpenes, the essential oils of medicinal mushrooms. Reishi probably contains the highest proportion of triterpenes, although they are found in all medicinal mushrooms. These are messenger and defense substances in the mushrooms that have an antioxidant, anti-inflammatory and immune-boosting effect in the human organism.

Other ingredients include statins, which inhibit excessive cholesterol formation, and glycoproteins and lectins, which are among the most powerful immunomodulators found in nature.

Medicinal mushrooms as immunomodulating adaptogens

Fungi have always had the same enemies as humans.

What we know as a mushroom is the so-called fruiting body. The actual tree is under the ground - the so-called mycelium. The mycelium has a huge surface area, sometimes only one cell layer thick, and thus has a very large area of ​​attack against pathogens. Therefore, mushrooms have developed strong defense mechanisms over the course of evolution. When we eat mushrooms, these substances can have the same effect in the body as in the mushroom.

Mushrooms can bring our immune system back to its biological optimum, restore balance and thus have an immune-modulating effect. Medicinal mushrooms are therefore also known as adaptogens: that is, they do exactly what the body lacks: restore basic immunity when the immune system is weakened. In the case of allergic reactions, autoimmune diseases, etc., they reduce the immune reaction.

How can this adaptogenic effect of medicinal mushrooms be explained biochemically?

All mushrooms contain branched fiber, the so-called beta-glucans. These are high-molecular polysaccharides where the body does not know exactly whether it is food or a pathogen, so our body puts the immune system "on standby" and makes it competent. In other words, medicinal mushrooms train the immune system: not too weak, but also not so strong that it overreacts in the form of autoimmune reactions or severe inflammation. This small stress stimulus, which leads to the body being stronger than before, is called "hormesis" and means nothing other than the hypothesis formulated by Paracelsus that small doses of pathogenic substances can have a positive effect on our body.

The positive effect of beta-glucans on the immune system has now been proven by numerous studies.See also https://pubmed.ncbi.nlm.nih.gov/33322069/ “β-glucans also have immune-modulating effects, leading to their investigation as adjuvant agents for cancers (solid and hematological malignancies), for immune-mediated conditions (eg, allergic rhinitis, respiratory infections), and to enhance wound healing. The therapeutic potential of β-glucans is evidenced by the fact that two glucan isolates were licensed as drugs in Japan as immune-adjuvant therapy for cancer in 1980.”

Furthermore, this study from 2017, for example, shows the positive influence of beta-glucans on upper respiratory tract diseases in older people: https://pubmed.ncbi.nlm.nih.gov/28606567/

Specifically, the immune system is stimulated via so-called "Toll-like receptors" (TLR), of which TLR-2 is particularly relevant for the beta-glucans from fungi. TLRs are part of our innate immune system and serve to recognize pathogen structures (structures that occur on or in pathogens) so that the body can distinguish between endogenous and foreign substances. If such structures are recognized, the TLRs control the activation and modulation of the antigen-specific (so-called "acquired") immune system.

This function of medicinal mushrooms has also been proven by scientific studies. For example, people who regularly take medicinal mushrooms have a higher number of leukocytes and these are also highly differentiated (see e.g. https://pubmed.ncbi.nlm.nih.gov/25866155/). After taking a handful of shiitake mushrooms daily for four weeks, a doubling of NK cells (natural killer cells) or 60% more T cells could be demonstrated.

Myelodysplastic syndrome (MDS), which is a series of diseases of the bone marrow in which too few functional blood cells are produced,  There are promising studies – including on the immunomodulatory effect of Maitake: https://pubmed.ncbi.nlm.nih.gov/25351719/ “Maitake was well tolerated. “Enhanced in vitro neutrophil and monocyte function following treatment demonstrate that Maitake has beneficial immunomodulatory potential in MDS.”

There are also numerous studies on the immune-modulating properties of Agaricus blazei. A very recent in vivo study on humans, for example, suggests an improvement in liver values ​​in hepatitis B patients: https://pubmed.ncbi.nlm.nih.gov/18370584/ “The mushroom Agaricus blazei Murill extract normalizes liver function in patients with chronic hepatitis B.”

There are also numerous studies on beta-glucans from yeast, especially for virus defense: The mucous membranes and the immune system around the mucous membranes are particularly active thanks to the beta-glucans and can fight off viruses well.

Medicinal mushrooms for gastrointestinal diseases

In order to understand the effect of medicinal mushrooms on the gastrointestinal tract, let’s first take a closer look at it:

Toxins and pathogens always first come into contact with the epithelium, ie the top layer of the mucous membrane tissue. The epithelium in the gastrointestinal tract is very thin, especially in the small intestine. It has to keep pathogens out, but at the same time absorb micronutrients and is therefore a very sensitive system that can easily become unbalanced.

The epithelium in the gastrointestinal tract is covered with a layer of mucus, the so-called mucus layer, which on the one hand represents a mechanical barrier, but also contains certain substances (antibodies, defensins, immune proteins) that are intended to prevent infection of the epithelium.

Let's start our journey through the gastrointestinal tract at the top of the esophagus. Inflammation of the esophagus that affects the epithelium usually comes from the stomach.It should be noted that heartburn can be caused by either an over- or under-acidic stomach: If the stomach is over-acidic, it wants to get rid of the excess acid. If the stomach is under-acidic (often occurs in people with autoimmune diseases), the effect is as follows: the stomach acid protects us from pathogens. A lack of stomach acid means that there are about 1000 times as many bacteria in the stomach, which ferment food components, among other things, creating gases that rise from the gastric juice into the lower esophagus, burst and cause heartburn.

If we travel from the esophagus through the gastrointestinal tract into the stomach, we have to talk about a small bacterium that about every second person has (as a small child, you often get it from your parents or even a cat): Helicobacter pylori. If the immune system is intact, this bacterium usually does not cause any major problems. But if the immune system is weakened or if the stomach is over- or under-acidic, it nests in the mucous membrane of the stomach and irritates it (gastritis = inflammation of the stomach lining). It drills through our mucus layer like a corkscrew into the stomach lining and creates holes in the stomach wall. It encapsulates itself in a shell of urea and thus protects itself from stomach acid, but also from the immune system and antibiotics.

If stomach acid drips through these holes onto the underlying tissue layer, it can cause serious ulcers and even stomach cancer. After all, stomach acid is about as acidic as a car battery!

Which medicinal mushrooms should be used for diseases of the stomach and esophagus?

Reishi and Hericium in combination are the first choice for diseases of the stomach and esophagus:

Reishi increases the production of antibacterial substances in the mucus layer of the esophagus and stomach, especially soluble IgA (immunoglobulin that is present in mucous membranes and protects the epithelium from pathogens) and defensins. See also: https://pubmed.ncbi.nlm.nih.gov/16798741/ “Reishi polysaccharides induce immunoglobulin production through the TLR4/TLR2-mediated induction of transcription factor Blimp-1”

Hericium has a number of specific triterpenes that can thicken the mucus layer again by increasing the production of mucins (the structural, protective component of mucus) and carbohydrate structures and thus stimulating the intestinal epithelium to grow (therefore also important for leaky gut) = “patches the hole”. See also: https://pubmed.ncbi.nlm.nih.gov/29455967/ “Gastroprotective activity of polysaccharide from Hericium erinaceus against ethanol-induced gastric mucosal lesion and pylorus ligation-induced gastric ulcer, and its antioxidant activities”

Hericium can also selectively kill the Helicobacter bacteria without affecting other "good" bacteria. Hericum also inhibits the attachment of Helicobacter to the stomach wall. See also: https://pubmed.ncbi.nlm.nih.gov/30806251/ “In Vitro and In Vivo Inhibition of Helicobacter pylori by Ethanolic Extracts of Lion's Mane Medicinal Mushroom, Hericium erinaceus (Agaricomycetes)”

The stomach is followed by the small intestine. It is 6-7 meters long, very thin (thinner than a hair) and, when unfolded, is as large as half a football field. This large surface area is necessary to absorb nutrients, but - precisely because it is so thin - represents a large area of ​​attack for pathogens.

A typical disease of the small intestine that medicinal mushrooms can help with is the so-called “leaky gut.” These are microscopic holes in the intestine.Small intestine cells only have an average lifespan of about five days, as they are constantly exposed to toxins, pathogens, etc., so they have to regenerate quite frequently. Some substances even reduce the lifespan to just about two days. If, for example, the micronutrients required for the regeneration of small intestine cells are missing and substances such as gluten break the connection between the cells, then undigested food proteins or toxins can enter the body through these microscopic holes, which promotes various chronic diseases, such as autoimmune diseases, diabetes, allergic diseases, high blood pressure. Autoimmune diseases in particular are very often associated with leaky gut.

Analogous to the process of the gastric mucosa already described, Hericium can also accelerate the regeneration processes in cases of leaky gut by stimulating the growth of the intestinal epithelium. However, in cases of leaky gut, it takes significantly longer than in the stomach, at around 6-8 months, until the mucosa is "patched" and regenerated.

It is always important not to rely solely on the mushrooms, but to always keep an eye on all micronutrients: If, for example, the intestinal cells lack building materials and growth factors due to vitamin D deficiency, the diet or lifestyle should be changed or, in this case, vitamin D should be supplemented and gluten, for example, should be eliminated from the diet.

Another typical small intestine disease is fungal infection by Candida albicans, which can cause flatulence, abdominal pain or diarrhea. Colonization of the small intestine by bacteria or Candida is usually associated with colon dysbiosis, ie an imbalance in the intestinal flora, or with hypoacidity in the stomach, so that pathogens reach the small intestine via the stomach.

In these cases, shiitake is the first choice because it is a natural antibiotic and can effectively remove pathogens from the small intestine. As a result, many people experience a detoxification reaction when taking shiitake in large quantities or as a concentrated extract, which is often misinterpreted as intolerance.

For the antimicrobial effect of shiitake, see also https://pubmed.ncbi.nlm.nih.gov/15773410/ “The juice of this mushroom at a concentration of 5% from the volume of the nutrient medium was found to produce a pronounced antimicrobial effect with respect to C. albicans, S. aureus, E. faecalis, E. coli O-114 and to stimulate the growth of E. coli M-17. Bifidobacteria and lactobacteria exhibited resistance to the action of L. edodes juice.”

Let's move on to the end of the gastrointestinal tract, the large intestine. This is not as long as the small intestine, but very wide. There are a few trillion microorganisms in the intestinal flora that live in harmony with one another. If the immune system no longer properly monitors what is happening in the large intestine (disturbed communication with the intestinal flora), or if one type of microorganism becomes dominant and displaces others, an imbalance occurs.

The intestinal flora can then be brought back into balance with medicinal mushroom extracts. Hericium and Reishi are also the first choice for the large intestine, because there too the mucus layer and the epithelium must be constantly regenerated and the immune system must be properly trained. It is also known that the polysaccharides of the mushrooms can bring the intestinal flora back into balance - see for example:

https://pubmed.ncbi.nlm.nih.gov/32693144/ “Moreover, mushroom polysaccharides also act as prebiotics and modulate the composition of gut microflora; and thus, can reduce insulin resistance. The present review discusses the pathophysiology of diabetes and, elaborates some potential mushroom species that are known to have antihyperglycemic activities.Different mushroom polysaccharides modulating the composition of gut microflora in diabetic animal models have also been discussed.”

https://pubmed.ncbi.nlm.nih.gov/33322069/ “β-glucans have metabolic and gastrointestinal effects, modulating the gut microbiome, altering lipid and glucose metabolism, reducing cholesterol, leading to their investigation as potential therapies for metabolic syndrome, obesity and diet regulation, gastrointestinal conditions such as irritable bowel, and to reduce cardiovascular and diabetes risk.”

https://pubmed.ncbi.nlm.nih.gov/28885559/ “Mushrooms act as a prebiotics to stimulate the growth of gut microbiota, conferring health benefits to the host. In the present review, we have summarized the beneficial activities of various mushrooms on gut microbiota via the inhibition of exogenous pathogens and, thus, improving the host health.”

Furthermore, there are specific studies on Reishi and Maitake that have shown that they can regenerate the intestinal flora (including in type 2 diabetes) in animal models:

Reishi:

https://pubmed.ncbi.nlm.nih.gov/26102296/ “Our results indicate that G. lucidum and its high weight polysaccharides may be used as prebiotic agents to prevent gut dysbiosis and obesity-related metabolic disorders in obese individuals.”

https://pubmed.ncbi.nlm.nih.gov/31712153/ “Intake of Ganoderma lucidum polysaccharides reverses the disturbed gut microbiota and metabolism in type 2 diabetic rats”

https://pubmed.ncbi.nlm.nih.gov/30826407/ “Hypoglycemic activity and gut microbiota regulation of a novel polysaccharide from Grifola frondosa in type 2 diabetic mice”

When the intestinal flora works with us and not against us, it also produces substances that are needed elsewhere in the body. For example, almost all happiness hormones are located in the intestine (99.9% of our total serotonin content), and the large intestine is connected to the vagus nerve connected to the brain. Vitamins and short-chain fatty acids are also synthesized in the intestine.

This connection could also explain the positive effects of Hericium on depressive moods or sleep quality:

https://pubmed.ncbi.nlm.nih.gov/20834180/ “we investigated the clinical effects of H. erinaceus on menopause, depression, sleep quality and indefinite complaints, using the Kupperman Menopausal Index (KMI), the Center for Epidemiologic Studies Depression Scale (CES-D), the Pittsburgh Sleep Quality Index (PSQI ), and the Indefinite Complaints Index (ICI). Thirty females were randomly assigned to either the H. erinaceus (HE) group or the placebo group and took HE cookies or placebo cookies for 4 weeks. Each of the CES-D and the ICI score after the HE intake was significantly lower than that before. In two terms of the ICI, "insentive" and "palpitation", each of the mean score of the HE group was significantly lower than the placebo group. “Concentration”, “irritating” and “anxious” tended to be lower than the placebo group.”

Initial studies also suggest a positive influence on neurodegenerative diseases and improvement of cognitive abilities through Hericium, for example. https://pubmed.ncbi.nlm.nih.gov/31413233/ “In this study, we tested a randomized, double-blind, placebo-controlled parallel-group comparative study to evaluate the improvement of the cognitive functions by taking supplements containing fruiting body of H. erinaceus for 12 weeks. […] showed that oral intake of H. erinaceus significantly improved cognitive functions and prevented from the deterioration.”

Medicinal Mushrooms in Accompanying Cancer Therapy

Only about 5% of all cancers have clear genetic causes (source: https://www.aerzteblatt.de/archiv/61809/Erbliche-Krebserkrankungen ).The rest is due to lifestyle factors such as stress, lack of micronutrients, environmental toxins such as heavy metals or electromagnetic radiation, obesity, chronic infections such as Ebstein-Barr virus or Lyme disease, alcohol, etc.

This is also proven by migration studies, for example, of residents of a small town in Nigeria, where around 70% fewer cases of cancer occur than in our western, "modern" societies. It should be noted that the medical care in this small town is so good that it can be ruled out that these are simply undetected diseases. If these Nigerians then migrate to the USA, they suddenly have the same cancer risk as the American average. There are comparable studies with the same result, for example, for Japanese who migrate to Hawaii (https://pubmed.ncbi.nlm.nih.gov/1287741/ ).

How does a healthy cell become a cancer cell?

In order to turn a healthy cell into a cancer cell, various stages must be passed through - and medicinal mushrooms can intervene effectively at each of these stages:

DNA damage, for example caused by infections, inflammation, toxins, radiation, etc., must first trigger certain mutations that prevent the cell from activating the suicide program, known as apoptosis. As the process progresses, the cell's metabolism is then changed and switches to anaerobic lactic acid metabolism. The cancer cell begins to grow uncontrollably. Normally, the body has built-in "brakes" for this uncontrolled growth, but these brakes are also bypassed. At this point, a small, degenerated tumor cell is present, about 1 mm in size. Almost everyone has these so-called microtumors within them from a certain age. And the point at which this microtumor turns into a malignant cancerous tumor is a process called angiogenesis: the tumor sends out messenger substances and encourages the body to form blood vessels from pre-existing blood vessels in order to supply it with oxygen and nutrients. The tumor can then continue to grow and form metastases via the blood in the body.

Every day, around 20 tumor cells develop in the body, but they are usually recognized and eliminated by our immune system. An intact, strong immune system is therefore a crucial factor in cancer prevention.

How can medicinal mushrooms help in prevention and therapy?

Fungi actively protect cells from environmental toxins, viruses, radiation, etc., but also ensure that the immune system recognizes and eliminates degenerated cells more quickly. They also influence the power plants of our cells, the so-called mitochondria, and can help prevent the metabolism from going into an anaerobic state, where it only ferments and no longer produces energy properly.

The effect of medicinal mushrooms in the context of angiogenesis is crucial, as they prevent blood vessels from being recruited and the tumor from growing through the formation of certain messenger substances. Shiitake, for example, plays a relevant role here with its specific beta-glucan “lentinan”: https://pubmed.ncbi.nlm.nih.gov/30373628/ “Lentinan inhibits tumor angiogenesis via interferon γ and in a T cell independent manner”

See also https://pubmed.ncbi.nlm.nih.gov/15234192/ “Fungal polysaccharopeptide inhibits tumor angiogenesis and tumor growth in mice”

For example, a 2009 study on breast cancer risk in a rural region of China showed that women who drank an average of one cup of green tea a day and ate 4 g of dried or 40 g of fresh mushrooms a day had a 60% lower risk of breast cancer than the comparison group.See: https://pubmed.ncbi.nlm.nih.gov/19048616/ “Dietary intakes of mushrooms and green tea combine to reduce the risk of breast cancer in Chinese women”

In China and Japan, some mushrooms are already approved for conventional cancer therapy, e.g. Maitake and Shiitake extracts as an infusion.

In complementary cancer therapy, the following medicinal mushrooms are also used in the West and are also the most researched: Reishi, almond mushroom, Maitake, Coriolus and Shiitake (especially for breast and colon cancer).

Reishi, for example, can increase the response rate to chemotherapy by about 40%, according to a scientific study. See also:

https://pubmed.ncbi.nlm.nih.gov/29141563/ : “Evidence from in vitro and in vivo studies has demonstrated that GLP possesses potential anticancer activity through immunomodulatory, anti-proliferative, pro-apoptotic, anti-metastatic and anti-angiogenic effects.”

https://pubmed.ncbi.nlm.nih.gov/27045603/ "G. lucidum could be administered as an alternative adjunct to conventional treatment in consideration of its potential of enhancing tumor response and stimulating host immunity. G. lucidum was generally well tolerated by most participants with only a scattered number of minor adverse events. No major toxicity was observed across the studies.”

Thanks to their (pentacyclic) triterpenes, all of the above-mentioned mushrooms also have antitumor and chemoprotective effects and strengthen the immune system.

There are numerous studies on Shiitake and Maitake in particular on strengthening basic immune competence during chemotherapy, i.e. basic immune activity can be maintained by administering the medicinal mushrooms mentioned. Example: Maitake: https://pubmed.ncbi.nlm.nih.gov/14977447/ “Maitake D-Fraction prevented metastatic progression, lessened the expression of tumor markers, and increased NK cell activity in all patients examined. Thus maitake D-Fraction appears to repress cancer progression and primarily exerts its effect through stimulation of NK activity.”

There are also reviews on almond mushroom (Agaricus blazei) and Maitake that show that chemotherapy-related side effects could be reduced by 70-80%, so that the quality of life was somewhat maintained.

The butterfly mushroom (Coriolus) contains two glycoproteins (proteins with sugar content), namely PSP and PSK. Studies have shown that the survival rate increases significantly (up to 40%) when this fungus is given in parallel with chemotherapy (https://pubmed.ncbi.nlm.nih.gov/32466253/ ).

A very recent review from 2020 focusing on Reishi and Coriolus also shows their positive effects in the context of accompanying cancer therapy: https://pubmed.ncbi.nlm.nih.gov/33685191/

Conclusion

In conclusion, it should be noted that scientific studies in the western world have already confirmed many of the positive effects attributed to medicinal mushrooms - some on humans, many so far only on animals. Due to these promising results, the number of studies has increased dramatically in the last three years, so it can be assumed that the importance and use of medicinal mushrooms will also increase significantly in the west in a few years.

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