For thousands of years humans have used medicinal mushrooms for their healing potential. A rich folkloric tradition has passed the knowledge of mushrooms down through the ages, particularly in Japan and China where mushrooms are supported by decades of scientific research and are imbedded in the cultural consciousness. Researchers in the U.S., however, have only recently begun to explore these fascinating organisms for their medicinal properties. As a nutritional supplement category, the future looks bright as long as clinical studies continue to yield positive results supporting the mushroom's reputation as a carrier of powerful healing constituents with the ability to improve human health.

Mushroom Primer
Although we are better informed about the plant kingdom than the fungal kingdom, from an evolutionary standpoint, fungi are actually closer relatives to humans than plants. Because we share more common genes with fungi than we do with plants, theory suggests that fungi could possibly impart greater health benefits to our body's systems. In his book, MycoMedicinals: An Informational Treatise on Mushrooms, Paul Stamets, founder and director of research, Fungi Perfecti, Olympia, WA, explained, "As fungi and animals share a more recent common ancestry than with plants, protozoans and bacteria, fungal medicines are active against many diseases that afflict humans. A peculiarity of nature is that we suffer from many of the disease organisms that afflict fungi, but in general, are not susceptible to those infecting plants. Many scientists believe this relationship occurs because we are more closely related to fungi than to any other kingdom, having shared a common ancestor more than 460 million years ago, and thus developed defenses against mutual microbial enemies."

The fungal kingdom is largely obscured from our view. What we see are mushrooms, or the "fruit" of the mycelium, which is the living body of a fungus usually hidden in a food source like wood, for example. Mushrooms grow in several different forms. Polypores, which are the oldest mushrooms, are usually found on trees in wooded areas and have small pores on their underside. The most common mushrooms are of the gilled variety, which form the well known shape of an umbrella. Some mushrooms are even parasitic in nature, growing on insects.

The variety of mushroom species discovered is vast. Researchers have identified up to 270 mushrooms with medicinal benefits, however, that may be just a small fraction of the actual mushrooms existing in the wild that have yet to be found. In terms of nutraceuticals, the mushroom category has been built upon a handful of mushrooms most commonly found in dietary supplements, including maitake (Grifola frondosa), reishi (Ganoderma lucidum), shiitake (Lentinula edodes), cordyceps (Cordyceps sinensis), turkey tail (Trametes versicolor) and lion's mane (Hericium erinaceus). Some up-and-coming mushrooms that have received a lot of attention in the research community are agaricus (Agaricus brasiliensis), oyster mushrooms (Pleurotus ostreatus) and AHCC® (Active Hexose Correlated Compound).


Culture Clash
There is a huge disparity in the perception of mushrooms between Asian cultures and ours here in the U.S. where we have developed mycophobia, or a fear of mushrooms, according to experts. On the other hand, mushrooms are so highly revered in Asian cultures that at one point in Chinese history cordyceps were considered a cultural treasure only to be eaten by the emperor.

The tradition of folklore that has been carried on through generations in Asian cultures forms a sharp contrast when compared to the empirical nature of modern medicine, which dominates Western culture. Explaining this culture gap was David Law, president, Gourmet Mushrooms, Inc., Sebastopol, CA. "Western culture, especially over the last 500 years with the advent of modern pharmacology, is evidence based. However, traditional Chinese medicine (TCM), and Eastern medicine as a whole, is based on thousands of years of folk wisdom," he said. "Modern medicine uses a single ingredient to attack a single illness whereas Eastern medicine looks at the body as a whole and approaches illness from a broad spectrum."

In Japan and China, mushrooms are used not only as natural therapeutic remedies for illness and disease, but also play a large role in the daily diet, according to Kristin Schierenbeck, M.S., C.N.S., certified nutrition specialist, Quality of Life Labs, Inc., Purchase, NY. "Although awareness of medicinal mushrooms is increasing here, the U.S. still has not accepted herbs or botanical medicine as mainstream medicine, which may be partly due to a lack of human clinical research on the subject."

Going into further detail about the connection between diet and health was Jeff Chilton, president, NAMMEX, Gibsons, British Columbia, Canada. "Eastern cultures have understood the concept of food as medicine for a long time. They look at a lot of their foods as being health promoting," he said. "That's a new concept for us over here. We've only recently begun to accept that foods, such as mushrooms, can actually be medicines as well. People are beginning to take more responsibility for their own health, so now we're looking not just at our diet, but we're looking at how we can supplement the diet with more things that are going to keep us healthy longer. As we move forward in the future I believe diets are going to be designed around this Eastern concept of food as medicine."


Immune Enhancers
The body's immune system is its main defense against pathogens such as bacteria and viruses. The active constituents-polysaccharides-found in most mushrooms are beneficial to a wide range of immune-suppressing conditions such as cancer, liver disease and diabetes.

Quality of Life Labs' Ms. Schierenbeck said the polysaccharides in mushrooms, in particular alpha and beta glucans, have an effect on white blood cells of the immune system. "The immune system is made up of several types of white blood cells and cytokines found in most tissues of the body. During an immune response, white blood cells such as lymphocytes, macrophages, helper T cells (T cells), natural killer cells (NK cells) and lymphokine activated killer cells (LAK) act to destroy invading microbes," she explained. "Cytokines, such as interferon (gamma interferon), interleukin-2 (IL-2), interleukin-12 (IL-12) and tumor necrosis factor (TNF), act to increase the activity of certain white blood cells, protecting the body against viruses and abnormal cells."

Although the polysaccharides found in mushrooms have drawn the most attention when it comes to examining the medicinal properties of mushrooms, Fungi Perfecti's Mr. Stamets says that it is not just beta glucans that stimulate an immune response. "What defines a species is its unique molecular architecture. While all mushrooms have certain compounds in common, they are never exactly the same," he explained. "The way to look at mushrooms is as little minature chemical factories that are producing an enormous assortment of novel constituents. Some constituents are common in groups of mushrooms, but so many of them are unique to the species in which they occur." Other medicinally active compounds in mushrooms are glycoproteins, ergosterols, triterpenes and antibiotics.

Going into further detail, Mr. Stamets discussed mushrooms' synergistic mode of action. "Mushrooms are immune modulators, which tend to bring the immune system back to a state of normalcy without causing over stimulation. These are natural substances that tend to be very high in their molecular weights, so they require digestion in order to be broken down," he said. "As the compounds are being digested they break apart into smaller molecular weight sub-constituents. It is that pathway of breaking down these large molecular complexes into smaller units that creates a cascade of sub-constituents that individually used in concert activate the immune system. For this reason if a consumer is seeking to fortify his or her immune system, a multiplicity of mushrooms activates far more receptor sites in the immune system."


Mushroom Trends
In terms of trends, currently the most significant is that Western medical science is looking very seriously at medicinal mushrooms for preventive as well as adjuvant therapies. Maitake and shiitake may be the most well known medicinal mushrooms with the most research, however, other mushrooms such as cordyceps, agaricus, oyster mushrooms and AHCC have received much attention over the past few years.

The reishi mushroom has been around for thousands of years and has long been venerated in Asian cultures. According to NAMMEX's Mr. Chilton, reishi is the most important of the medicinal mushrooms. "Reishi has compounds that most other mushrooms do not, including triterpenes, which are found in many longevity herbs," he said. "Western scientists are finally getting funding to do the research that they need to see exactly what the benefits are. Right now we're working with two different research groups in the U.S. that are conducting scientific studies on reishi."

Discussing the background of AHCC was Quality of Life Labs' Ms. Schierenbeck. "AHCC is a medicinal mushroom extract product containing a highly bioactive hexose molecule, derived from the combination of basidiomycetes mushrooms. This patented mushroom complex is most commonly used in patients who have immune suppressed diseases such as cancer, HIV/AIDS, diabetes and hepatitis," she said. "According to the research, AHCC enhances normal immunity by improving the function of immune system cells. It is for this reason that AHCC is used not only by chronically ill patients but also by anyone interested in optimum health and immune system support."

Furthermore, Ms. Schierenbeck said, AHCC is extracted from the hybridization of several species of mushroom mycelia, including basidiomycetes mushrooms. "There are many active ingredients found in AHCC, including oligiosaccharides from alpha and beta-glucans, and a substance unique to AHCC known as GI-saccharide," she explained. "It is the GI-saccharide that makes AHCC unique and different to any other mushroom or immune support complex. Both the oligiosacharrides and GI-saccharide have a low molecular weight, making AHCC easy to digest and more bioavailable."

In an upcoming study, the National Institutes of Health (NIH), Bethesda, MD, has provided Fungi Perfecti with funding to conduct a small clinical study using oyster mushrooms to mitigate the negative effects of protease inhibitors, which are antiviral agents used to treat AIDS patients. According to Mr. Stamets, this is the first clinical study approved by NIH on medicinal mushrooms. "The problem with protease inhibitors is that they interfere with lipid metabolism in the liver causing a hyper accumulation of LDL," he said. "Oyster mushrooms contain a natural isomer of Lovastatin®, which is an FDA-approved drug for lowering cholesterol. Oyster mushrooms also contain antiviral agents and glycoproteins, which are anti-HIV agents." In addition to the oyster mushroom study, Mr. Stamets said that the NIH has also provided funding for a much larger breast cancer study with a few hundred people using turkey tail mushrooms.

Discussing the agaricus mushroom group, Mr. Stamets said it is interesting because they contain aromatase inhibitors, which are associated with the decline in the growth rate of tumors, breast cancer in particular. "Things that inhibit aromatase are associated with a decline in tumor growth. The theorum is we all have cancer all the time, it's just that the immune system scavenges away the disease cells when your immune system is functioning properly," he said. "When we become destabled or diseased, then the immune system can't keep up. Mushrooms that contain aromatase inhibitors are looked upon favorably because they can mitigate the effect of the proliferation of these disease cells."

Cordyceps, which grow on caterpillars, represent another mushroom group that has been gaining increasing attention in the U.S. According to Brien Quirk, technical director, Draco Natural Products, San Jose, CA, studies in Japan have shown cordyceps to have a wide range of applications. "It has been documented that Chinese emperors used cordyceps for everything from rejuvination from sickness and fatigue and there have been some studies on its positive effects on erectile function," he said. "Pharmacological studies have also shown that there's an active compound in cordyceps called cordyceptic acid, which makes cordyceps an effective energy tonic."


Looking Ahead
The consensus among experts is that these are exciting times for mushrooms. Over the past decade the growing level of interest in mushrooms from the medical community as well as the increasing numbers of studies conducted on mushrooms and articles written about them have driven the market forward and will continue to do so.

According to Fungi Perfecti's Mr. Stamets, mushrooms will be used more and more as an adjuvant therapy in combination with conventional medicine. "Physician's don't have anything to give their patients for the immune system," he said. "Conventional medicine is good at surgery and bombarding the system with radiation and chemotherapy. Physicians really are in need of something to bolster the immune system and mushrooms fit that bill."

Unlike a lot of herbs, which hit peaks and valleys in the market, mushrooms have experienced slow, steady growth in a very orderly manner, said NAMMEX's Mr. Chilton. "When I first developed my company back in 1989 there was hardly any awareness of medicinal mushrooms at all. Growth in the mushroom category will depend upon the volume of information that gets out to the public and ultimately to manufacturers," he said. "We've only begun to realize the potential of medicinal mushrooms in the West. In Asia right now they've estimated medicinal mushroom products to be a $2 billion industry. The research that will be coming out in the next several years is going to do nothing but bolster this industry's reputation."

Using another example from Asia to illustrate the market potential mushrooms hold was Yori Takeda, marketing and sales manager, Atlas World USA, Inc., Redondo Beach, CA. "Over the past five to six years the benefits of agaricus mushrooms became well publicized in Japan and the market grew close to $450 million in retail sales of just agaricus," he said. "With continued research and education, the mushroom market will also witness such growth in the U.S."