The shiitake mushroom proves looks aren’t everything: What could be scruffier or more taciturn-looking as it hunkers down on your grocer’s produce shelf? Don’t be so quick to judge, though. This mushroom-with-an-attitude is a study in contrasts: earthy but ethereal, unimpressive but magnificent. It performs in a cast of potent fungi known as the medicinal mushrooms, which number more than 200 worldwide and include others of sterling repute, such as reishi and maitake. Unlike the Asians and Europeans who have cherished these mushrooms for millennia, we in North America are just beginning to discover their merits.
Medicinal mushrooms enhance the body’s general resilience and vigor, stimulate the immune system, and confer antioxidant benefits. Since the 1960s, science has been catching up to tradition, and many clinical studies now demonstrate that these mushrooms do indeed shore up the body’s defenses against such afflictions as cancer, infection and heart disease.
• Bonus Recipe:Sautéed Shiitake and Bok Choy
Our friend the shiitake (Lentinula edodes) is one you’ve probably sampled. This mushroom’s meaty texture and rich, woodsy flavor make it a culinary favorite in any dish calling for mushrooms, and it is especially good in meatless cuisine. Originally from China, shiitakes have been cultivated in North America since at least the 1980s.
Shiitake protects against certain cancers, tumors and infections–the latter through antiviral and antibiotic actions. How shiitake executes its anticancer campaign is not fully understood, but a constituent known as lentinan appears pivotal. Widely studied, lentinan from shiitake is an approved drug in Japan, used mainly as an adjunct to conventional cancer chemotherapy. Controlled clinical trials using injected lentinan with standard chemotherapy show it is effective against stomach, colorectal and prostate cancers. In 1999, a study published in Hepatogastroenterology found that lentinan increased one-year survival of gastric-cancer patients to 49 percent compared to no increase without lentinan. And a trial conducted at the Saitama Cancer Center in Japan reported that five-year survival of patients with metastatic prostate cancer was 43 percent with lentinan treatment versus 29 percent without it.
Shiitake is especially rich in lentinan, a complex polysaccharide of the beta-D-glucan family found in sources such as oats, barley, yeast, algae, bacteria and mushrooms. Beta-D-glucans stimulate the body’s macrophages and other immune system weaponry to arrest cancer or tumor initiation, growth and spread. They also thwart bacterial, parasitic and viral pathogens, including those of AIDS and hepatitis B.
Is eating the mushroom itself as effective as taking lentinan extract? In a therapeutic sense, probably not, since levels found in whole foods typically are lower and more variable than from controlled botanical extracts. But long-term benefits can accrue by eating the mushrooms as a component of a balanced diet, especially considering that shiitakes (and other medicinal mushrooms) contain minerals, vitamins, proteins and other beneficial chemicals, including linoleic acid and ergosterol, which help lower cholesterol and the risk of arteriosclerosis.
Maitake (Grifola frondosa), also known as “dancing mushroom,” might have gotten its name from a time long ago when people who found them reputedly danced for joy–not surprising, considering these treasures were worth their weight in silver! Found in the northern temperate forests of Asia and Europe, eastern Canada and the northeastern United States–and cultivated increasingly in North America–maitake is much in demand by chefs and gourmands for its sublime taste and texture and its distinctive, earthy aroma. It is equally pursued for its medicinal prowess.
Maitake, like shiitake, is an immune booster and cancer fighter. Extracts of its beta-D-glucans administered with whole maitake powder and standard chemotherapy promoted cancer regression or significant symptom improvement in 58 percent of liver cancer patients, 69 percent of breast cancer patients and 62 percent of lung cancer patients (but much less in patients with leukemia, stomach cancer or brain cancer), according to a 2002 report in Alternative Medicine Review. Other clinical studies show that the extracts increase production of interleukin-12, which activates the body’s natural killer cells. Many additional benefits have been indicated for maitake, including possible regulation of cholesterol, diabetes, high blood pressure, viral infection and liver disease.
The Role of Reishi
A rare find in the wild, the Asian reishi (Ganoderma lucidum) mushroom is so bitter you won’t want to bite into its cap. And even if you tried, it would be too woody. In fact, reishi’s polished hardness and bonsai-evoking appearance has made it a prized shelf ornament. But its medicinal properties have won many North American fans, who readily acquire imported reishi from China. The mushroom is traditionally sliced and simmered for tea or boiled in soups, then the pieces are discarded.
Reishi’s bitter properties are due to its rich supply of terpenoids, elite plant chemicals that can work as antioxidants, immune-system stimulants, blood pressure regulators and anti-cholesterol agents. Reishi’s terpenoids include ganoderic acid, ganaderiol and lucidumol, all with antiviral properties. Together with its other constituents–coumarins, which are natural blood thinners; phospholipids, which are anti-inflammatory and nerve protective; and the beta-D-glucans–reishi stocks a comprehensive medicinal cabinet that may well render it the mushroom of choice for health.
Dried reishi powder has been a popular anticancer agent in China since ancient times. A review in Integrative Cancer Therapies indicates that it deters even highly invasive breast and prostate cancer cells from spreading and becoming established in the body. And a clinical study from Immunological Investigations found that patients with advanced-stage cancer showed improvements in their immune responses when treated with reishi polysaccharide extracts for 12 weeks.
Even in healthy people, reishi boosts antioxidant capacity, as demonstrated in a recent study published in the International Journal of Food Sciences and Nutrition. This study showed that patients receiving either 10-day supplementation with encapsulated reishi (0.72 grams daily, equivalent to about 6.6 grams of fresh mushroom) or a single dose of 1.1 grams had an acute spike in plasma antioxidant capacity, without apparent toxic effects.
As an aid to healthy aging and longevity, reishi also helps detoxify the liver, prevent arteriosclerosis and manage Alzheimer’s disease (for which a Japanese reishi product has been patented). Other studies demonstrate anti-allergic, anti-inflammatory and antibacterial actions–and the research continues. With all these dividends, reishi may be one bitter pill you will want to swallow.
Getting the Best
These special mushrooms are available fresh, dried, canned, powdered or in extracted forms from supermarkets, health-food stores and mail-order sources. As a general health supplement, try a daily serving of about 5 grams of dried reishi or maitake (about 1 medium mushroom) or 5 to 15 grams dried shiitake (1 to 3 mushrooms).
For best results, remember these tips when buying and using medicinal mushrooms:
Before using dried mushrooms, soak them in lightly salted or sugared hot water or stock for about an hour. Powders and extracts should be used according to package instructions and the advice of your health-care provider. (Warning: Mushrooms can interact with some over-the-counter and prescription drugs; check with your health-care provider.)
Store fresh mushrooms in paper bags in the coldest part of your refrigerator, and eat them within seven days of purchase. Canned mushrooms last about a year, while dried ones sealed in plastic and stored in the freezer can last indefinitely.
If possible, choose mushrooms grown on natural wood logs rather than sawdust. You will pay more for log-cultured mushrooms, but they tend to taste better, last longer and shrink less during cooking. Their medicinal quality should be better, too.
Tough Living Makes Mighty Medicine
Why are medicinal mushrooms so gifted? Their strength comes from doing one of the most arduous jobs in nature–digesting dead or dying hardwood trees like oaks, elms and plums. Shiitake, maitake and reishi are wood composters that infiltrate tough tree trunks and roots using threadlike fingers, called mycelium, to digest and recycle nutrients back to the forest floor for the next generation of plants. Mushrooms are the fruit bodies that sprout when growing conditions are sufficiently cool and moist.
To do their job, these fungi must outcompete other fungi and microbes while dismantling the vast chemical complex of the tree. They must be aggressive yet defensive, a feat accomplished through biochemical combat. Harvested mushrooms possess potent bioactive chemicals, as well as nutrients gleaned from the tree. The button mushrooms commonly sold in supermarkets are far less competitive in nature and less active medicinally.
Sources of Healing Mushrooms
• Earthy Delights, (800) 367-4709, www.earthy.com
• Fungi Perfecti, (800) 780-9126, www.fungi.com
• Gourmet Mushroom, (800) 789-9121, www.gmushrooms.com
• Marx Foods, (866) 588-6279, www.marxfoods.com
• Mountain Rose Herbs, (800) 879-3337, www.mountainroseherbs.com
• Mushroom Harvest, (740) 448-7376, www.mushroomharvest.com
• Mushroom People, (800) 692-6329, www.mushroompeople.com
• Now Foods, (888) 669-3663, www.nowfoods.com
• Quality of Life, (877) 937-2422, www.q-o-l.com
The reference list for this article is extensive. For the complete list, click here.
Gina Mohammed, Ph.D., is a plant physiologist living in Sault Ste. Marie, Ontario, Canada.