Americans are certainly losing their fear of fungus. Gone are the days when the white button variety was as exotic as mushrooms got. Now a walk into nearly any natural products store will reveal an array of fresh mushroom varieties. Likewise, a mere glance at restaurant menus from coast to coast will show them dotted with exotic words like shiitake, portobello and truffle oil. However, it is the medicinal quality of mushrooms that is really putting fungus on the map.
While medicinal mushrooms have been used in China and Japan for more than 3,000 years to boost immunity and fight diseases such as cancer, only in the last decade has their power begun to be recognized in the United States. Supplements companies have responded to the call, and there is an assortment of mushroom products to help your customers lead healthier lives.
"Mushrooms are a wonderful material to support the body in doing what it is supposed to do," says David Law, chief financial officer of Gourmet Mushrooms, a cultivator of edible and medicinal mushrooms in Sebastopol, Calif. "When your body is not in sync and can't properly fight off germs, mushrooms provide information that really helps the body go back to a balanced state. They are very good immune support.'
In more scientific terms, a number of compounds in fungi have been found to stimulate the function of the immune system, inhibit tumor growth and boost intestinal flora. Particularly, mushroom substances called terpenoids help kill bacteria and viruses and exert anti-inflammatory effects, while complex chain-like sugars called polysaccharides have been shown to exert antitumor and immuno-stimulating properties. "Science is only beginning to illuminate the power of mushrooms," says Ellen Shnidman, head of scientific affairs for Maitake Products Inc., in Ridgefield Park, N.J., a maker of raw material and finished-product mushroom supplements. "Mushrooms contain some amazing health-promoting components."
The specific polysaccharide in mushrooms most noted for this immune-boosting effect is beta-glucan. Found also in oats and certain yeasts, beta-glucan works by looking an awful lot like bacteria. When ingested, the body thinks an invader has entered. In response, the immune system boosts its production and activity of various white blood cells, therefore strengthening its defenses. Beta-glucan's ability to keep the immune system strong has led to it frequently being called "the new echinacea."
Beta-glucan has also been shown to lower cholesterol by binding to it and pulling it out of the body. Results from a number of double-blind trials using various sources of beta-glucan indicate such reductions. For example, in a 1999 study published in the American Journal of Clinical Nutrition, a daily dose of 15 g of beta-glucan fiber given for eight weeks was shown to significantly lower cholesterol.
Beta-glucan and other components in mushrooms also have the ability to calm the immune system when it is overstimulated. Termed adaptogens, these substances help balance the body and give it what it needs, depending on what is going on. They boost immune function when it is low and tone it down when it is overactive, keeping the system at homeostasis.
Since each mushroom has its own slightly different form of beta-glucan and other polysaccharides, it has its own distinct protective properties. "For people who are in good health who want a bit of insurance, my suggestion is always take a blend of different mushrooms, especially those with different morphologies," says Law.
For example, reishi (Ganoderma lucidum) is a polypore, which grows on the stumps of decaying trees. Shiitake (Lentinus edodes) is a gill fungus, and cordyceps (Cordyceps sinensis) is an insect parasitic fungi that grows on the back of a caterpillar. Each mushroom develops a special morphology as an adaptation to the environment in which it grows. In its ecosystem, it has to compete with other microbes, fungi, bacteria and so forth, and in so doing, it develops a strong defense system against its surrounding dangers.
Unlike mushrooms, humans don't stay in one ecosystem. We are highly mobile, coming in contact with people from all over the world—and with the unfamiliar pathogens they carry. Supplementing with a blend of mushrooms that have built up defenses to an array of pathogens should provide broad-spectrum protection.
Maitake, shiitake and reishi
Although a dozen or so varieties of medicinal mushrooms are used regularly in Asia, only a handful currently grace American supplements store shelves. Of them, maitake (Grifola frondosa), shiitake and reishi are perhaps the biggest stars.
Also known as the "dancing mushroom," maitake mushrooms are becoming quite popular due to the recent isolation and trademark of a substance called D-fraction, which has been shown to exert anti-tumor activity and supports the immune system in general. But taking the whole mushroom has its benefits too. It appears the mushroom also contains co-factors that either enhance the absorption of D-fraction or add to its usefulness as an immune supporter.
In their book Medicinal Mushrooms: Ancient Remedies For Modern Ailments (M. Evans and Company, 2002), George M. Halpern, M.D., and Andrew H. Miller cite studies showing the polysaccharides in maitake can also help lower cholesterol, balance blood sugar and battle prostate cancer.
The shiitake mushroom is a culinary staple in many Asian cultures, and it's widely consumed here too. In Chinese medicine, shiitakes are used to boost chi, activate blood flow and fight off everything from colds to heart trouble. Shiitakes contain a well-studied chemical called lentinan, shown to boost immune function and reduce cancer tumors. In addition, shiitakes appear to help the body make interferon, a powerful anti-viral substance, as well as help battle asthma, frequent colds and flu, and an overgrowth of Candida albicans.
The reishi mushroom is also known for helping to produce interferon, thereby exerting antiviral effects in the body. Recent test-tube studies have shown reishi to be effective against influenza A, as well as heart disease, hypertension and arthritis. In Japan, reishi as a supplement is formally listed as a treatment for people with cancer. A study of 250 cancer patients by Fukumi Morishige, M.D., Ph.D., showed that reishi has great promise for managing cancer, particularly when teamed with megadoses of vitamin C daily. In addition, studies have indicated it helps protect against the effects of radiation treatment.
As science continues to accumulate data on the healing properties of mushrooms, your customers will undoubtedly be asking which ones to take. "I would look for a product produced in the United States that has an organic certification, because a lot of products coming from the Far East are tainted with heavy metals," says Law.
Mushroom products can be found in powdered, dried, liquid capsule and tablet form. "Look for products made from the fruiting body of the mushroom, because that is where the most potent compounds reside," says Shnidman. While products containing a blend of mushrooms will provide your customers with a hefty dose of general immune boosting, to treat specific conditions, suggest they consult their health-care practitioner.
The curiosity of cordyceps
In nature, cordyceps (Cordyceps sinensis) is a parasitic fungus that feeds on caterpillars. Modern cultivation methods now grow cordyceps on grain, but its healing properties are just as potent. A 2003 placebo-controlled study presented at the American Physiological Society's annual scientific conference showed cordyceps increased energy. Over a 12-week period, 131 healthy but sedentary men and women (ages 40 to 70) took 3 g of a cordyceps supplement per day or a placebo. Both groups completed a 1-mile walk before and after the study. Results showed that those who took cordyceps raised their oxygen capacity by 5.5 percent, which made the post-study walk easier and less tiring. —L.K.
Linda Knittel is a Portland, Ore.-based freelance writer.
Natural Foods Merchandiser volume XXVI/number 3/p. 102, 104