Friday, November 9, 2007

Shiitake: The Incredible Natural Health Herb From The East

The Shiitake mushroom is the most widely cultivated specialty mushroom in the world and is both a prized medicine as well as a culinary delight. Because of its traditional use in folk medicine and its availability, it has been the subject of intense research. Cochran's review of medicinal mushrooms, "Medical Effects" (Biology and Cultivation of Edible Mushrooms, Academic Press, 1978), list Shiitake as having antifungal, anti-tumor, and antiviral effects.

The shiitake (Lentinula edodes) is an edible mushroom native to East Asia. It is generally known in the English-speaking world by its Japanese name, shiitake listen (literally "shii mushroom", from the Japanese name of the tree that provides the dead logs on which it is typically cultivated). In Chinese, it is called xiānggū (literally "fragrant mushroom"). Two Chinese variant names for high grades of shiitake are dōnggū ("winter mushroom") and huāgū ("flower mushroom", which has a flower-like cracking pattern on the mushroom's upper surface); both are produced at colder temperatures. Other names by which the mushroom is known in English include Chinese black mushroom and black forest mushroom. In Korean it is called pyogo, in Thai they are called hed hom ("fragrant mushroom"), and in Vietnamese they are called nấm hương ("fragrant mushroom").

The species was formerly known as Lentinus edodes and Agaricus edodes. The latter name was first applied by the English botanist Miles Joseph Berkeley in 1878. Shiitake are native to China but have been grown in both Japan and China since prehistoric times
. They have been cultivated for over 1000 years; the first written record of shiitake cultivation can be traced to Wu Sang Kwuang, born during the Song Dynasty (960-1127 A.D.). However, some documents record the uncultivated mushroom being eaten as early as 199 A.D.

During the Ming Dynasty (1368-1644 A.D.), physician Wu Juei wrote that the mushroom could be used not only as a food but was taken as a remedy for upper respiratory diseases, poor blood circulation, liver trouble, exhaustion and weakness, and to boost qi, or life energy. It was also believed to prevent premature aging.

Before 1982 the Japanese variety of these mushooms could only be grown in traditional locations using ancient methods. In the late '70s, Gary F. Leatham published a doctoral thesis based on his research on the budding and growth of the Japan Islands variety; the work helped make commercial cultivation possible world-wide, and Dr. Leatham is now known in the industry as the "Father of Shiitake farming in the USA."

Benefits From This Natural Health Herb
Shiitake is now one of the most popular sources of protein in Japan, and a major staple in China, and other parts of the Pacific Rim. As a food source, it has the combined attributes of being appetizing, nourishing, dietetic and healthful. Shiitake has adequate nutritional qualities to serve as a main dish. It adapts well to recipes as a meat substitute.

The antiviral effects are believed to be caused by Shiitake's ability to produce interferon. Researchers have reported that consumption of Shiitake mushrooms lowers blood cholesterol levels by as much as 45 percent. The most dramatic results occurred when high-cholesterol foods were eaten simultaneously with Shiitake . In two human studies, cholesterol dropped 6 to 15 percent when the amount of Shiitake consumed was nine grams per day or approximately 10 dried medium-sized mushrooms.

Additionally, the ability of shiitake to accelerate the metabolism and excretion of cholesterol was first reported in 1966 by Kaneda and Tokuda. The Donko and Koshin varieties of shiitake produced a 45% and 36% reduction in total plasma cholesterol respectively. The active principle is an amino acid named eritadenine. Eritadenine lowers all lipid components of serum lipoproteins in both animals and man. It exhibits very low toxicity and is effective when administered orally. One hundred twenty-four derivatives of eritadenine have been synthesized and tested. Patents for consumable products capitalizing on shiitake hypocholesterolemic effect have been issued. Lowering plasma lipids by a method as simple as consuming a food or beverage is very appealing to the health-conscious public.

Shiitake has also shown the capacity to lower high blood pressure in laboratory animals. Lentinan, which is the name given a highly purified polysaccharide fraction extracted from Shiitake mushrooms, is an approved drug in Japan. It is generally administered by injection and has been used as an agent to prolong survival of patients in conventional cancer therapy as well as in AIDS research. Lentinan is commercially available for clinical use. "In Japan, mushroom extracts have become the leading prescription treatment for cancer" . Lentinan is not only useful for cancer treatment, but may also prevent the increase of chromosomal damage induced by anti-cancer drugs. With lentinan there are no known side effects of any serious nature. In Japan treatment of mice with lentinan prior to radiation provided complete protection from a reduction in white blood cell counts.

But in the west, we are still in the dark ages; making immunopotentiators available to patients undergoing radiative therapy has yet to be accepted here. There are also documented cases of greatly reduced side-effects from radiation and chemotherapy in patients who took herbal immunopotentiators at the same time. The noncytotoxic nature of polysaccharides offer a way to destroy unwanted cells without damaging the host. Chihara writes that "The leading principles of the function of lentinan resides in the fact that it can cure patients by restoring their homeostasis, and through enhancement of their intrinsic resistance against diseases." As a functional food, Shiitake contains all eight essential amino acids in better proportions than soy beans, meat, milk, or eggs as well as a good blend of vitamins and minerals including vitamins A, B, B12, C, D and Niacin. Shiitake produces a fat-absorbing compound which aids in weight reduction.

No comments: