I’ve always loved mushrooms—not just for their rich, smoky flavor but also for their mystery, their spring from the dark, and their reach back to ancient cultures. Some scholars believe that the ambrosia of Greek literature was actually intoxicating mushrooms, the secret behind the Eleusinian Mysteries. Egyptian pharaohs prized the fungi so much they declared them exclusively royal food. And for thousands of years, the Chinese have used them not only to enhance meals but also to heal bodies, a wisdom Americans are finally picking up on. Since the early 1990s, sales of exotic mushrooms—which experts believe offer the biggest health boost—have doubled in the U.S.
Nutritionists have long known that many types of mushrooms have plenty of health perks to recommend them. They’re full of B vitamins, which are important for brain and nervous system connections and for healthy skin and hair, says nutritionist Felicia Busch, author of The New Nutrition. A single cup of the raw vegetable packs the fiber of a whole-grain slice of bread. And mushrooms offer a healthy dose of selenium, an antioxidant linked to reduced risks of cancer and heart disease. To top it off, they’re easy on the waistline—about 20 calories in five medium-sized ones.
But recently, studies have begun to show that some of the exotic varieties—shiitake, maitake, reishi, oyster, and enoki—can do much more. These fungi have been shown to boost immune activity, lower blood fats, and halt the growth of cancer cells, changing the mushroom’s status from that of mere steak décor to one of our diet’s most powerful health-promoters.
“The gold is in the beta glucans,” says Harry G. Preuss, professor of physiology, medicine, and pathology at Georgetown University Medical Center and author of Maitake Magic. Hidden in the cell walls of the more unusual mushrooms, these sugar molecules boost immune activity in a variety of ways and with different effects. In one Japanese study last year, for instance, an extract of maitake mushrooms activated helper T cells, thought to fight both cancer and infection, and upped the output of interferon and interleukin, chemical substances that help regulate immune responses. And in a study of cancer patients, beta glucans were shown to suppress tumor growth and soften the effects of radiation and chemotherapy.
Preuss is also discovering that maitakes have beneficial effects on blood pressure and insulin levels in diabetic mice and rats. Within six hours of sipping an extract, the test rats responded with a 25 percent drop in blood pressure, and within days, insulin levels fell by the same amount. Preuss speculates that the mushroom extract works by increasing the number and sensitivity of insulin receptors or by sharpening the message from the receptors to the cells.
Mushrooms also impress Shiuan Chen, a professor of biological science at the City of Hope Cancer Center in Los Angeles. When Chen and his colleagues studied seven common vegetables, including white button mushrooms (portobellos are part of this family), the mushrooms showed great success in suppressing estrogen production. That’s important, says Chen, since estrogen suppression in post-menopausal women appears to protect against breast cancer. And in Chen’s studies of mice with cancerous breast tumors, those given mushroom extracts had a 20 to 30 percent reduction in tumor size within five to six weeks.
So just how much of these delicious disease-fighters do we need to eat to protect our health? “That’s such a Western question,” says Karen Koffler, director of integrative medicine at Evanston Northwestern Healthcare in Evanston, Illinois. “We can’t really say, but just the act of buying mushrooms is a declaration that you are taking a step to care for your health.”
The Chinese hedge their bets by mixing different types in stir-fries and soups, as does Koffler. Her favorite stir-fry: shiitakes and portobellos with kale, broccoli, red cabbage, and sun-dried tomatoes served over brown basmati rice and topped with almonds.
David Grotto, director of the nutrition education department at the Block Center for Integrative Cancer Care in Evanston, Illinois, favors grilled shiitakes and portobellos marinated first in balsamic vinegar, olive oil, and garlic: “Put those on a whole-grain bun and you’ve got a cancer- and heart-disease-fighting sandwich,” he says. He also freezes puréed cooked mushrooms in ice trays, then pops a cube or two into soups or marinara sauce.
I, for one, have resolved to eat mushrooms as often as I can. I now buy them at least once a week—and not just for their mystery. As I stir dried shiitake and oyster mushrooms into the winter stew I make on a cold Sunday, the broth darkens within 20 minutes and turns more fragrant, exotic. Opening a bottle of red wine, I ask my husband to stoke up the fire. I’m ready for crusty bread and smoky mushrooms—the earth coming to my plate.