Long a symbol of longevity in Asia because of their health-promoting properties, shiitake mushrooms have been used medicinally by the Chinese for more than 6,000 years. More recently, their rich, smoky flavor has endeared them to American taste buds. These exotic hearty mushrooms can now be found in supermarket shelves across the U.S. throughout the year.
Like other mushrooms, these specialty mushrooms are as mysteriously unique as they are delicious. While often thought of as a vegetable and prepared like one, mushrooms are actually a fungus, a special type of living organism that has no roots, leaves, flowers or seeds.
Shiitake, maitake, and reishi mushrooms are widely referred to as "medicinal mushrooms" due to their long history of medical use, particularly in oriental medicine traditions. It's important to distinguish, however, between extracts and medicinal preparations made from these mushrooms and their appearance as whole foods in an everyday diet. Most of the medicinal research on shiitake mushrooms has been conducted on laboratory animals or on individual cells studied in a laboratory setting. There are hundreds of lab and animal studies that clearly document the medicinal properties of shiitake mushroom extracts. As important as these studies are in a medical context, they are still very different from studies that examine shiitake mushroom as a common and beloved food.
In contrast to the wealth of medicinal research on shiitake mushrooms, there are very few studies on shiitake mushrooms in the human diet. Among the human dietary studies that do exist, however, there is a clear message about shiitake mushrooms: they can provide us with some fantastic health benefits. Below are areas of health support that make the top of our list for shiitake mushrooms when enjoyed as a whole food.
Immune Support
No health benefit is better documented for shiitake mushroom than immune support. In fact, the immune support track record for this mushroom is fascinating. On the one hand, numerous studies have shown the ability of whole shiitake mushrooms to help prevent excessive immune system activity. On the other hand, an equal number of studies have shown the ability of shiitake mushrooms to help stimulate immune system responses under certain circumstances. In other words, from a dietary perspective, shiitake mushrooms appear able to enhance immune function in both directions, giving it a boost when needed, and cutting back on its activity when needed. It's important to note that dietary shiitake mushroom intake - unlike intake of medicinal shiitake extracts - has not been shown to be strongly suppressive of the immune system or strongly activating. From our perspective, this finding makes sense. We wouldn't want our everyday foods to strongly suppress or strongly activate any body system. What we would want from our foods is support of body systems under a variety of circumstances - and that is exactly what we get from shiitake mushrooms with respect to our immune system.
Cardiovascular Benefits
The cardiovascular benefits of shiitake mushrooms have been documented in three basic areas of research. The first of these areas is cholesterol reduction. d-Eritadenine (also called lentinacin, or lentsine, and sometimes abbreviated as DEA) is one of the most unusual naturally occurring nutrients in shiitake mushrooms that has repeatedly been shown to help lower total blood cholesterol. This nutrient is actually derived from adenine - one of the building blocks (nucleotides) in the mushroom's genetic material (DNA). The beta-glucans in shiitake mushrooms are also very likely to contribute to its cholesterol-lowering impact.
Anti-Cancer Benefits
Most of the research on shiitake mushrooms and cancer has been conducted on laboratory animals or on individual cells in a laboratory setting and has involved mushroom extracts rather than whole mushrooms in food form. For this reason, our understanding of the anti-cancer benefits of shiitake mushrooms as a whole, natural food is still preliminary. But based on research to date, we believe that adding shiitake mushrooms to your diet is likely to offer you anti-cancer benefits, especially with respect to prevention of prostate cancer, breast cancer, and colon cancer.
Other Benefits
The special combination of antioxidants found in shiitake mushrooms together with their highly flexible support for immune system function make them a natural candidate for providing us with protection from a variety of problems involving oxidative stress and immune function. This includes rheumatoid arthritis (RA), an area that has begun to interest shiitake mushroom researchers. Although research in this area is preliminary, we expect to see large-scale human studies confirming the benefits of shiitake mushrooms for prevention of RA.
Medicinal extracts from shiitake mushrooms have well-documented effects on a variety of micro-organisms, including bacteria, fungi, and viruses (including human immunodeficiency virus-1, or HIV-1). While we have yet to see large-scale human studies on whole food intake of shiitake mushrooms and decreased susceptibility to colds, flu or other problems related to unwanted activity of micro-organisms, this is a very likely area for future food research and discovery of health benefits.
