HERBS THAT BOOST IMMUNE FUNCTION
4. MEDICINAL MUSHROOMS*
Medicinal mushrooms like shiitake, reishi, oyster, maitake and chaga mushrooms can boost health when cooked and eaten, or when taken as a supplement.
Although we may not think of mushrooms as herbs, many of the world’s more than 38,000 species of mushrooms have medicinal uses. In his book Medicinal Mushrooms (Botanica Press, 1996), herbalist Christopher Hobbs writes that mushrooms have been valued throughout the world for thousands of years, both as food and as medicine.
Most of the knowledge about medicinal mushrooms comes from ancient Chinese medicine, where mushrooms were regarded as tonics. Tonics are considered to have non-specific beneficial effects, across several systems of the body, which do not decline over time.
Mushrooms are fungi. Fungi are a diverse group of eukaryotic single-celled or multinucleate organisms that live by decomposing and absorbing the organic material in which they grow, comprising mushrooms, molds, mildews, smuts, rusts, and yeasts.
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi (Basidiomycota, Agaricomycetes) that have a stem (stipe), a cap (pileus), and gills (lamellae) on the underside of the cap. These gills produce microscopic spores that help the fungus spread across the ground or its occupant surface. "Mushroom" describes a variety of gilled fungi, with or without stems, and the term is used even more generally, to describe both the fleshy fruiting bodies of some Ascomycota and the woody or leathery fruiting bodies of some Basidiomycota, depending upon the context of the word.
Medicinal fungi are those fungi which produce medically significant metabolites (breakdown products, generally small molecules) or can be induced to produce such metabolites using biotechnology. The range of medically active compounds that has been identified includes antibiotics, anti-cancer drugs, cholesterol inhibitors, psychotropic drugs, immuno-stimulants and even fungicides.
Although fungal products have been used in traditional and folk medicines, probably since pre-history, the ability to identify beneficial properties and then extract the active ingredient started with the discovery of penicillin by Alexander Fleming in 1928. Since that time, many additional antibiotics have been discovered and the potential for fungi to synthesise biologically active molecules useful in a wide range of clinical therapies has been extensively explored.
Medicinal mushrooms and fungi are thought to possess approximately 130 medicinal functions, including anti-tumour, immune-modulating, antioxidant, free radical scavenging, cardiovascular, anti-hypercholesterolemic, anti-viral, anti-bacterial, anti-parasitic, anti-fungal, detoxification, hepatoprotective, and anti-diabetic effects. Many mushrooms contain biologically active compounds in fruit bodies, and cultured mycelium. Numerous bioactive polysaccharides or polysaccharide–protein complexes from the medicinal mushrooms appear to enhance innate and cell-mediated immune responses, and exhibit anti-tumour activities in animals and humans.
There are many mushrooms that have medicinal properties. The following five mushrooms, commonly available, have been selected to illustrate how they boost immunity and have other significant health benefits.
- Shiitake (Lentinula Edodes)
Shiitake are edible mushrooms native to East Asia.
Basic research is on-going to show how shiitake mushrooms affect the immune system, possess antibacterial properties, reduce platelet aggregation and provide other anti-disease properties.
It is generally accepted that shiitake is a potent immune-boosting mushroom. It also has anti-tumour and anti-viral properties, and can lower blood pressure and cholesterol. Hobbs (see above) writes that shiitake is "used medically for any and all diseases involving depressed immune function, including cancer, AIDS, environmental allergies, candida infection, and frequent colds and 'flu.".
- Reishi (Ganoderma Lucidum) (Lingzhi in Chinese)
Reishi mushrooms are an immune modulator, regulating and fine-tuning the immune system.
As well as having immuno-stimulant properties, they are also known to calm anxiety, and are often used as a general tonic.
Reishi is primarily composed of complex carbohydrates called water-soluble polysaccharides, triterpeniods, proteins and amino acids. Researchers have identified that water-soluble polysaccharides are the most active element found in Reishi that have anti-tumour and blood pressure lowering effects, and well as immune-modulating effects.
Another major active ingredient found in red Reishi is triterpenes, called ganoderic acids. Preliminary studies indicated that ganoderic acids help alleviate common allergies by inhibiting histamine release, improve oxygen utilisation and improve liver function. Triterpenes are bitter in taste, and the level of the triterpene content contained can be determined by the bitterness.
- Oyster (Pleurotus Ostreatus)
Oyster mushrooms have been used for thousands of years as a culinary and medicinal ingredient. The white mushrooms resemble oysters, and can be found growing in the wild on dead trees or fallen logs. They have a rich history in traditional Chinese medicine from as early as 3,000 years ago, particularly as a tonic for the immune system, according to Christopher Hobbs. They are easy to grow at home.
They boost the immune system.
Oyster mushrooms contain ergothioneine, a unique antioxidant produced by fungi.
They also have significant antibacterial activity.
- Maitake (Grifola Frondosa)
Maitake mushrooms typically grow in clusters at the base of trees, particularly oaks. They are commonly known among English speakers as ram's head or sheep's head.
Maitake has been used in traditional Chinese and Japanese medicine to enhance the immune system. One active constituent in Maitake for enhancing the immune activity was identified in the late 1980s as a protein-bound beta-glucan compound.
Researchers have also indicated that whole maitake has the ability to regulate blood pressure, glucose, insulin, and both serum and liver lipids, such as cholesterol, triglycerides, and phospholipids.
Maitake mushrooms are rich in minerals (such as potassium, calcium, and magnesium), various vitamins (B2, D2 and niacin), fibre and amino acids.
- Chaga (Inonotus Obliquus)
Chaga grows as a parasite on birch and other trees. The sterile conk is irregularly formed, with the appearance of burnt charcoal. Unlike most mushrooms which are soft, chaga is hard, almost as hard as wood. It is unique, nothing like common mushrooms.
Chaga has high levels of special phenols which are pigment-like. These phenolic compounds are known as chromogenic complex. Chaga can be up to 30% chromogenic complex by weight. Chaga also contains superoxide dysmutase, a powerful antioxidant.
Chaga is a health food that supports the entire body, especially the immune system.
It is an adaptogen (it modifies the human body's response to stress).
There are two primary types of mushroom supplements:
- Mushroom concentrates or extracts. Most of these are so-called hot water extracts, where either the mushroom mycelia or fruit body is boiled for extended periods of time to extract the long chain polysaccharides. What you get basically is a concentrated form of these beta-glucans. But the enzymes, the proteins, the amino acids and the dietary fibre are either denatured, destroyed, or simply discarded.
- A whole-food mushroom powdered-pill product is generally a better alternative, if you are reasonably healthy and looking to maintain optimal health and help maintain the various organs in the body, especially the immune system.
Various preparations are available in capsule form: for example, Pure Reishi capsules, 500mg, “extracted from the 4 most potent strains of Reishi mushrooms” (www.iherb.com).
Mushrooms as Whole Foods
Despite the availability of mushroom supplements, the best way to boost your immune system with medicinal mushrooms is to eat them.
*Copyright 2016: The Huntly Centre.
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