Nothing compares to the earthy fragrance and taste of mushrooms freshly sauteed in a bit of olive oil and garlic. But did you know that mushrooms are far more special than their delicious taste suggests? Neither plant nor animal, mushrooms are classified in the kingdom of fungi. But mushrooms are even more unique within the fungi kingdom, because they are the complex fruiting body of the fungal organism.
Given their uniqueness, it's not surprising that mushrooms have piqued interest for their potential medicinal value. For thousands of years, people have treasured them for both their rich flavor and therapeutic effects. According to Donald Abrams, M.D., professor at the University of California-San Francisco and director of Osher Center for Integrative Medicine, mushrooms have long been used medicinally in Asia, and they are now becoming more accepted around the globe for therapeutic purposes.
A number of well-known drugs originated in the fungi kingdom, including penicillin, two statins (lovastatin and squalestatin,) and cephalasporin. And, Ganoderma lucidum (known as the "mushroom of immortality" in China) is responsible for $1.5 billion in worldwide extract sales because of its purported medicinal value.
>'Super' mushrooms for health
Naturally low in calories and fat, mushrooms only contain 18 to 28 calories per three-ounce serving, depending on the variety. What's even more important is what mushrooms contain.
Abrams reports that "In the '60s and '70s, scientists began to isolate special active constituents in mushrooms." These constituents include beta-glucans (sugar molecules), proteins, carbohydrates, fats, vitamins, trace elements and naturally-occurring plant compounds like sterols, phenols, and terponoids.
Researchers also point out that mushrooms have a number of bacteria, yeasts and molds that may hold health-promoting promise.
The study of mushrooms' health benefits has focused primarily on their anti-cancer activity, antioxidant action and immune-enhancing benefits. A few studies have looked into other potential benefits, including weight management and satiety, and reduction in levels of blood lipids and glucose. Mushroom beta-glucans may be the secret ingredient, as they appear to have immune-stimulating and cholesterol-lowering effects, as well as anti-cancer activity, according to a November 2009 study in Nutrition Reviews.
>Mushrooms take on cancer
According to Abrams, mushrooms may be especially beneficial in cancer treatment, with some varieties under study for their direct anti-cancer activity, as well as immune-enhancing response in cancer patients.
"Mushrooms are widely used as an adjuvant therapy for cancer in Japan and China," adds Abrams. A number of studies have already demonstrated that some varieties might reduce the risk of certain cancers, as well as inhibit tumor growth. At City of Hope, a National Cancer Institute-designated Comprehensive Cancer Care Center in Duarte, CA, researchers are currently investigating mushrooms' potential in reducing or even stunting breast and prostate cancer growth in human clinical studies.
>An unlikely vitamin D source
Another reason mushrooms are on scientists' radar is because they're an excellent source of today's most buzz-worthy vitamin -- vitamin D. Linked with many important health benefits, including maintaining healthy bones, teeth and muscles; cancer prevention, autoimmune disease protection, immune defense and mental health promotion, vitamin D is not easily found in many food sources.
Similar to the way in which humans absorb sunlight through the skin and convert it to vitamin D, mushrooms contain ergosterol that converts to vitamin D when exposed to sunlight. Thus, these mushrooms contain high levels of vitamin D from exposure to ultraviolet light under controlled conditions.
For example, portabella mushrooms exposed to ultraviolet light contain 387 international units (97 percent daily value) of vitamin D per 84 gram (about three ounces) serving. The most popular mushroom in America, white or button mushrooms (Agaricus bisporus) contain an abundance of ergosterol, according to an April 2009 study published in the Journal of Agricultural and Food Chemistry.
The Australian research team reported that commercial production of button mushrooms enriched with vitamin D through exposure to sunlight might be a practical approach for improving consumer health. Today, more mushroom growers are exposing their mushrooms to UV light to increase vitamin D levels.