The use of mushrooms for treating disease, so common in China and Japan, is conquering the West. One of the main sales pitches for "medicinal" mushrooms is that they have been used in Oriental medicine for thousands of years. Does that mean you should buy some, though?
Modern Western and traditional Eastern medical traditions are based on entirely different principles. In China, any illness is treated as an imbalance between Yin and Yang in the body, a malfunction in the flow of Qi or life energy that permeates the universe. As such, an illness is healed by restoring the balance, which is achieved by acupuncture, herbal medicine, and so on. More than 250 species of mushrooms are used in various folk medicines as treatment for all kinds of ailments, from cancer to baldness, as well as a way to prevent aging and rejuvenate the body. This venerable trandition makes medicinal mushrooms ever more popular in the West; however, scientists are not so thrilled so far. Let’s look at three of the most popular species and what research has to say about them.
Shiitake mushroom (Lentinula edodes). Apart from being very tasty and a staple of Japanese cuisine, shiitake is used to slow aging, prevent heart disease, and treat cancer. This effect may be due to a chemical compound called lentinan. Among the very few studies conducted on shiitake, some show that lentinan may prolong the life of patients with advanced cancer (details here) and perhaps prevent obesity in rats, but so far there are no clear conclusions for humans.
Reishi mushroom (Ganoderma lucidum), known as lingzhi in China, is cultivated on wood and straw; this fungus has been used in traditional medicine for over 2000 years as a cure for heart disease, diabetes, and cancer. Some in vitro studies do show that compounds extracted from reishi can kill cancer cells (you can read more here), but so far there has been very little study on humans.
Finally, chaga mushroom (Inonotus obliquus) is rock-hard and grows on trees; it is used in Eastern Europe and Russia for the same purposes as shiitake and reishi in Asia; and just like with others, so far research results are promising but few. Chaga extract may be able to destroy cancer cells. Let’s note that none of these mushrooms seem to be toxic in any way.
As you see, so far there is no firm scientific proof that mushrooms can cure diseases. While study results are promising, injecting rats with a chemical is not the same as drinking hot mushroom tea! Much more in vivo study is needed to reveal if shiitake and chaga can actually treat heart disease or cancer. And while it is true that mushrooms have been used in China for millennia, the same can be said about powdered deer antlers, bird nests, turtle shells, and dry frogs. In the 20th century, the average lifespan in China has increased from 40 to 75 years, and much of it was due to the arrival of Western medicine in Asia. Nowadays, the Chinese themselves tend to choose Western-style clinics and medicines in case of real illness.
Since advertising of mushrooms is almost unregulated, distributors in the West often make outrageous claims about their powers. No toxic side-effects have been found, so these mushrooms won’t hurt you, but if you decide to include them in your diet, remember: in case of a serious health issue, go see a proper Western doctor!