09 Jan Shiitake Mushrooms
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.
What’s New and Beneficial about Shiitake Mushrooms
- Although immune system support has often received much of the spotlight in shiitake mushroom research, recent study results involving support of the cardiovascular system have caught the attention of many researchers. In particular, recent studies have shown the ability of shiitake mushrooms to help protect us against cardiovascular diseases (including atherosclerosis) by preventing too much immune cell binding to the lining of our blood vessels. In order for immune cells and other materials to bind onto our blood vessel linings, certain protein molecules—called adhesion molecules—must be produced and sent into action. By helping to block the adhesion molecule production process, substances in shiitake mushrooms can help protect our blood vessels. (The adhesion molecule production that is partially blocked by shiitake mushroom components includes the adhesion molecules ICAM-1, VCAM-1, and E-selectin.)
- Shiitake mushrooms have long been recognized as a very good, non-animal food source of iron. But a recent preliminary study has determined that the bioavailability of iron from shiitake mushrooms may be even better than we thought. Although conducted on laboratory animals (female rats) rather than humans, this study found the iron in dried shiitake mushroom to be equally as bioavailable as supplemental iron in the form of ferrous gluconate. (Ferrous gluconate is a very commonly used low-dose iron supplement.) While we don’t usually spotlight research on laboratory animals, we found this result to be especially promising for individuals who consume little or no animal products and are often looking for foods that can supply valuable amounts of bioavailable iron.
- Shiitake mushrooms can be one of the most sustainable foods in your diet! While the majority of shiitake mushrooms produced worldwide have been grown on sawdust block in a non-natural setting, it is fully possible for shiitake mushrooms to be produced on natural hardwood logs in a forest setting. This approach to shiitake mushroom production is called “forest farming” and it has become an especially popular way of growing shiitake mushrooms in the U.S, where there are now more than 200 shiitake mushroom growers. Unfortunately, forest farming is not a requirement for organic certification of shiitake mushrooms. However, all of the plant crop standards in the National Organics Program regulations apply to shiitake mushroom production, and so the combination of these two features—certified organic shiitake mushrooms that have also been forest farmed—can make a great food choice in terms of sustainable agriculture. Just look for the USDA’s organic logo on your shiitake mushrooms to determine if they are certified organic. Then check for information about forest farming on the packaging. If no information is provided, there is a good chance that your shiitake mushrooms were not forest farmed. For this reason, we encourage you to ask your store staff or contact the product manufacturer to determine if your shiitake mushrooms were grown on hardwood logs in a natural forest environment.
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.
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.
One especially interesting area of immune system support involves the impact of shiitake mushrooms on immune cells called macrophages. Among their many important activities, macrophage cells are responsible for identifying and clearing potentially cancerous cells from the body. In order to carry out this task, they need to be “activated” in a particular way. (In more scientific terms, their activated phenotype needs to reflect a higher level of interleukin 1-beta and tumor necrosis factor alpha, and a lower level of interleukin 10.) Shiitake mushrooms are able to help macrophage cells achieve this activated profile so that they can do a better job clearing potentially cancerous cells. Researchers refer to this result as an “anti-cancer immunity” that is enhanced by shiitake mushroom intake.
The most famous immune-supportive components in shiitake mushrooms are its polysaccharides. (Polysaccharides are large-sized carbohydrate molecules composed of many different sugars arranged in chains and branches.) Although many fungi are well-known for their polysaccharides, no single fungus has been more carefully studied than the shiitake mushroom. We know that this fungus is unique in its variety of polysaccharides, and especially its polysaccharide glucans. (Glucans are polysaccharides in which all of the sugar components involve the simple sugar glucose.) Among the glucans contained in shiitake mushroom are alpha-1,6 glucan, alpha-1,4 glucan, beta-1,3 glucan, beta-1,6 glucan, 1,4-D-glucans, 1,6-D-glucans, glucan phosphate, laminarin, and lentinan. Shiitake mushrooms also contain some important non-glucan polysaccharides, including fucoidans and galactomannins. The immune-related effects of polysaccharides in shiitake mushrooms have been studied on laboratory animals under a wide variety of circumstances, including exercise stress, exposure to inflammation-producing toxins, radiation exposure, and immunodeficiency. Under all of these circumstances, the polysaccharides in shiitake mushrooms have been shown to lessen problems. There is also some evidence that shiitake mushrooms’ polysaccharides can help lower total cholesterol levels.
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.
Another basic area of cardiovascular support involves the interaction between our cardiovascular system and our immune system. Recent studies have shown that shiitake mushrooms can help protect us against cardiovascular diseases (including atherosclerosis) by preventing too much immune cell binding to the lining of our blood vessels. In order for immune cells and other materials to bind onto our blood vessel linings, certain protein molecules—called adhesion molecules—must be produced and sent into action. By helping to block the adhesion molecule production process, substances in shiitake mushrooms can help protect our blood vessels. (The adhesion molecule production which is partially blocked by shiitake mushroom components includes the adhesion molecules ICAM-1, VCAM-1, and E-selectin.)
A final basic area of cardiovascular benefits involves antioxidant support. Chronic oxidative stress in our cardiovascular system (ongoing, oxygen-based damage to our blood vessel linings) is a critical factor in the development of clogged arteries (atherosclerosis) and other blood vessel problems. One of the best ways for us to reduce our risk of chronic oxidative stress is consumption of a diet rich in antioxidant nutrients. Shiitake mushrooms are a very good source of three key antioxidant minerals: manganese, selenium, and zinc. They also contain some unusual phytonutrient antioxidants. One of the best studied is ergothioneine (ET). This unique antioxidant is derived from the amino acid histidine, although it’s unusual since it contains a sulfur group of molecules that are not present in histidine itself. In studies on ET and our cells’ oxidative stress levels, one fascinating finding has been the special benefits of ET for cell components called mitochondria. Mitochondria use oxygen to produce energy for the cell. Heart cells have greater concentrations of mitochondria than most any other cell type in the body. For this reason, researchers believe that ET may be one of the key nutrients from shiitake mushrooms that provide us with cardiovascular support.
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.
Medicinal extracts from shiitake mushrooms have been studied much more extensively than the whole food itself. In cell and laboratory animal experiments, numerous components of shiitake mushrooms have been show to help block tumor growth, sometimes by triggering programmed cell death (apoptosis) in the cancer cells. These components have been collectively referred to as “anti-tumor mycochemicals” provided by shiitake mushrooms. Researchers have speculated that more than 100 different types of compounds in shiitake mushrooms may work together to accomplish these anti-tumor results. While the unique polysaccharides in shiitake mushrooms were first thought to be its primary anti-cancer compounds, scientists are now convinced that shiitake provides many non-polysaccharide substances that have anti-tumor effects.
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.
Shiitake mushrooms have brown, slightly convex caps that range in diameter from about two to four inches in diameter. They belong to the basidiomycete family of fungi. Until the early 1990’s, they were widely known by their scientific genus-species name of Lentinus edodes. However, during the late 1980’s and early 1990’s this genus-species name for shiitake mushrooms was largely phased out and replaced by a new genus-species name, Lentinula edodes.
The common name for this mushroom, “shiitake,” comes from the Japanese language. “Shii” in Japanese refers to wood belonging to the Pasania species of tree on which shiitake mushrooms naturally grow. “Take” simply translates as “mushroom.” You may sometimes also hear shiitake mushroom being referred to as the “Black Forest mushroom,” and they do indeed grow naturally in that German mountain range.
Other mushrooms with Asian roots that are also becoming more popular are reishi (Ganoderma lucidum) and maitake (Grifola frondosa). Reishi mushrooms usually have an antler or rounded, fan shape; the most popular type of reishi is red in color, although that is just one of the six colors in which they grow. Maitake mushrooms grow in a formation of clustered brownish fronds of fan-shaped petals and are commonly known as “Hen of the Woods.” These types of mushrooms are available in food markets specializing in Asian foods.
Shiitake (as well as reishi and maitake) mushrooms have grown wild since prehistoric times. Their therapeutic value has been prized in Asian countries, where they originated, for thousands of years. They play a critical role in Asian medicinal traditions and were noted in some of the first books on herbal medicine written thousands of years ago. In the past few decades, these mushrooms have become more popular in the United States as a result of an expanding body of scientific research supporting their numerous health benefits. The U.S. is currently home to approximately 200 commercial growers of shiitake mushrooms, and nearly half of those growers use forest farming to produce shiitake mushrooms in a natural forest setting using downed hardwood trees as the cultivation medium.
Although Japan was at one time the world’s largest producer of shiitake mushrooms, that distinction now goes to China, which produces over 80% of all commercially sold shiitake mushrooms. Japan, Korea and Taiwan also produce shiitake mushrooms, as does the United States. One quickly growing market for shiitake mushrooms is Brazil, which currently produces more shiitake mushrooms than any other South American country.
How to Select and Store
Shiitake mushrooms are available in many grocery stores throughout the country. If your local store does not carry fresh reishi or maitake mushrooms, investigate the Asian food stores in your area as they oftentimes carry these specialty mushrooms.
Look for mushrooms that are firm, plump and clean. Those that are wrinkled or have wet slimy spots should be avoided.
The best way to store loose shiitake mushrooms (as well as maitake or reishi mushrooms) is to keep them in the refrigerator in a loosely closed paper bag. They will keep fresh for about one week. Dried mushrooms should be stored in a tightly sealed container in either the refrigerator or freezer where they will stay fresh for six months to one year.
Tips for Preparing Shiitake Mushrooms
Mushrooms are very porous, so if they are exposed to too much water they will quickly absorb it and become soggy. Therefore, the best way to clean mushrooms without sacrificing their texture and taste is to clean them using minimal, if any, water. To do this, simply wipe them with a slightly damp paper towel or kitchen cloth. You could also use a mushroom brush, available at most kitchenware stores.
If the fresh mushrooms become dried out because of being stored for too long, soak them in water for thirty minutes.
The Healthiest Way of Cooking Shiitake Mushrooms
We recommend Healthy Sautéeing shiitake mushrooms for maximum flavor and nutrition. Heat 3 TBS of broth over medium heat in a stainless steel skilled. When broth begins to steam add sliced mushrooms and Healthy Sauté for 7 minutes. It is best to stir constantly for the last 4 minutes of cooking.
A Few Quick Serving Ideas
- Shiitake mushrooms are traditionally added to miso soup.
- Healthy saute mushrooms with onions and garlic. Serve as a side dish or as a topping for chicken, beef, lamb or venison. (Organic Grocer carries top brands of free range beef)
- To give your vegetable stock an extra depth, add dried shiitake mushrooms.
- For a quick and easy Asian pasta dish, healthy saute shiitake mushrooms with snap peas and tofu. Season to taste and serve over buckwheat soba noodles (or your favorite type of pasta).
WHFoods Recipes That Feature Shiitake Mushrooms
- Poached Eggs Over Collard Greens & Shiitake Mushrooms
- 5 Spice Onion Soup
- Shiitake Mushroom Seaweed Soup
- 15-Minute Steamed Halibut with Bok Choy
- 15 Minute Healthy Sauteed Chicken & Bok Choy
- 5-Spice Chicken in a Bowl
- Miso Stir-Fry
- Spicy Healthy Sautéed Tofu
- Spicy Vegetable Tart
- Asian Mushroom Saute
- Healthy Sautéed Shiitake Mushrooms
Shiitake Mushrooms and Purines
Shiitake mushrooms contain naturally-occurring substances called purines. Purines are commonly found in plants, animals, and humans. In some individuals who are susceptible to purine-related problems, excessive intake of these substances can cause health problems. Since purines can be broken down to form uric acid, excess accumulation of purines in the body can lead to excess accumulation of uric acid. The health condition called “gout” and the formation of kidney stones from uric acid are two examples of uric acid-related problems that can be related to excessive intake of purine-containing foods. For this reason, individuals with kidney problems or gout may want to limit or avoid intake of purine-containing foods such as shiitake mushrooms.
Like most fungi, shiitake mushrooms offer a unique variety of phytonutrients, including their well-known beta-glucan polysaccharides (especially lentinan and laminarin). A cholesterol-lowering nutrient called eritadenine (or lentinacin) is found in shiitake, as well as the recently discovered amino acid-like nutrient, ergothioneine. Shiitake mushrooms also offer a wide variety of conventional nutrients. They are an excellent source of copper, pantothenic acid, and selenium. They are a very good source of vitamin B2 and zinc. Additionally they are a good source of manganese, vitamin B6, niacin, choline, dietary fiber, vitamin D, and folate.
Introduction to Food Rating System Chart
In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn’t contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food’s in-depth nutritional profile that includes values for dozens of nutrients – not just the ones rated as excellent, very good, or good – please use the link below the chart.) To read this chart accurately, you’ll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food’s nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration’s “Reference Values for Nutrition Labeling.”
|Mushrooms, Shiitake, cooked
GI: not available
|pantothenic acid||2.61 mg||52||23.1||excellent|
|vitamin B2||0.12 mg||9||4.1||very good|
|zinc||0.96 mg||9||3.9||very good|
|vitamin B6||0.12 mg||7||3.1||good|
|vitamin B3||1.09 mg||7||3.0||good|
|vitamin D||20.30 IU||5||2.2||good|
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