Ganoderma mushrooms come in six species -- each with its own distinctive color -- but it's the red species, Ganoderma lucidum, that's cultivated throughout Asia and North America for its rumored healing powers. Known popularly as reishi, the mushroom thrives in decaying logs and tree stumps in coastal regions. Reishi's richly colored caps, which are high in fiber, vitamins and amino acids, are too tough for culinary purposes but have been used medicinally for thousands of years.
Uses: In traditional Chinese medicine, reishi is taken to enhance memory, fight fatigue and increase longevity. Recently reishi has been touted as a remedy for cancer, HIV, Hepatitis B, herpes, altitude sickness, high blood pressure and diabetes.
Dose: Usually, several hundred milligrams to several grams a day in separate doses, taken with food. Reishi comes in tincture, tea, powder and tablet form. Some herbal medicine purveyors and traditional Chinese medicine shops sell the dried mushrooms.
Precautions: Taking reishi continuously for months at a time can cause dry mouth and upset stomach. Some people may be sensitive to the mushroom and react by breaking out in hives or a rash. Certain compounds in the mushroom can slow the blood's clotting time, so people on anticoagulants should avoid reishi supplements.
Research: Most of the research on reishi has been conducted in China, Japan and Korea, where the mushroom has been used for millenniums. Reishi hindered the growth of bladder, colon and breast cancer cells in lab experiments and has provided promising results in animal cancer studies. Animal research also suggests the mushroom can treat peptic ulcers. Such studies suggest reishi acts by increasing the number of so-called natural killer cells, one of several types of cells in the body's immune system. Clinical trials are still lacking, though so far they suggest reishi is effective in reducing high blood pressure.
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-- Elena Conis