The shiitake mushroom proves that looks aren’t everything: What could be scruffier or more taciturn-looking as it hunkers down on your grocer’s produce shelf? Yet this mushroom with an attitude is a study in contrasts: earthy yet ethereal, unimpressive yet 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.
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, likely not, since levels found in whole foods typically are lower and more variable than from controlled botanical extracts. But by eating the mushrooms as a component of a balanced diet, long-term benefits can accrue, 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,” may 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 vigorously courted today by chefs and gourmands who celebrate 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
If shiitake seems taciturn, then reishi (Ganoderma lucidum) is downright recalcitrant. A rare find in the wild, this Asian 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. Nonetheless, 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.
The bitter properties of reishi reside in its abundant supply of terpenoids, elite plant chemicals with diverse defensive roles in nature. When we consume foods with terpenoids, they can serve as antioxidants, immune system stimulants, blood pressure regulators and anti-cholesterol agents. Reishi’s terpenoids are manifold and 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 individuals, 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 to 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
As a general health supplement, 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) is suggested. These mushrooms are available fresh, dried, canned, powdered or in extracted forms from supermarkets, health-food stores and mail order. Dried mushrooms should be soaked in lightly salted or sugared hot water or stock for about an hour before use. 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.)
Fresh mushrooms may be stored in paper bags in the coldest part of your refrigerator to avoid degradation, and they should be eaten 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 and, if frozen when fresh, have superior biochemical content over fresh ones consumed many days after harvest.
Most commercial mushrooms are cultivated. The best ones are likely those grown on natural wood logs rather than sawdust, which is commonly used today. You will pay more for log-cultured mushrooms, but they tend to taste better, last longer and shrink less during cooking. Logs are a far better food source than sawdust, so mushroom nutrient and medicinal quality should be higher.
What about toxicities or drug interactions with these mushrooms? They are generally well tolerated in moderate amounts, but some individuals experience allergic reactions, mostly from uncooked mushrooms. Shiitake powder may cause dermatitis with prolonged usage. Reishi can produce a dry throat and nose, gastrointestinal upset, dizziness, hypotension and bleeding, particularly when used with blood-thinning drugs. When first sampling medicinal mushrooms, try a single cooked mushroom or small serving of tea initially to gauge your body’s reactions. Then you may indulge more confidently in these exceptional gems of the forest.
Gina Mohammed, Ph.D., is a plant physiologist living in Sault Ste. Marie, Ontario, Canada. She is author of Catnip and Kerosene Grass: What Plants Teach Us About Life (www.CandlenutBooks.com).
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In the following recipes, maitake and shiitake may be used interchangeably.
Makes 1 serving
1 teaspoon chopped dried reishi
7 thin slices fresh gingerroot
1 cup water
1/2 teaspoon honey
Combine reishi, ginger and water in a small pan. Bring to a boil, then simmer for 10 minutes. Strain tea and stir in honey. Drink hot or cool.
SAUTÉED SHIITAKE AND BOK CHOY
Makes 2 servings
1 teaspoon olive oil
1 large clove garlic, finely chopped
21/2 cups Chinese bok choy, sliced into 1-inch segments
2/3 cup green onions, sliced
11/3 cups fresh shiitake mushrooms, caps only, washed and sliced
2 tablespoons shoyu soy sauce
Steamed rice, Belgian endive and sliced avocado
Heat oil in a skillet and cook the garlic on medium-high for about 1 minute. Add bok choy, green onions, mushrooms and soy sauce, and sauté for 2 to 3 minutes until the bok choy greens are wilted. Serve alongside steamed rice, a few endive leaves and sliced avocado.
ORANGE ROUGHY WITH MAITAKE AND ONIONS
Makes 4 servings
This mushroom topping can be served with any kind of fish. From Mitoku Company, www.mitoku.com.
1/2 cup dried maitake mushrooms
1 cup warm water
2 tablespoons extra virgin olive oil
1/2 medium onion, diced
Pinch of sea salt
2 teaspoons fresh lemon juice
2 teaspoons shoyu
1/4 cup chopped parsley
2 teaspoons fresh ginger juice (grate root and squeeze to extract juice)
Four 4 to 6-oz fillets orange roughy or other favorite fish
Soak maitake in water for 30 to 40 minutes, then gently squeeze out excess water and chop finely. (Save the soaking water for stock for soups or sauces.) Heat oil in a large skillet. Add onion and a pinch of salt, then sauté over medium heat for a minute. Add the maitake, lemon juice and shoyu. Sauté for 2 to 3 minutes, then cover and cook over medium-low heat for 5 minutes more. Add parsley and ginger juice, and toss well. Season the fish fillets with sea salt and place them over the mushroom mixture. Cover and cook over medium heat for 7 to 10 minutes, or until the fillets are just cooked. Serve the fish covered with the maitake-onion mixture, and garnish with parsley if desired.