Most of us recognize Shiitake mushrooms as delicious and edible mushrooms. They have a deep umami-rich flavor that bestows unique sensations in Asian cuisine. What many people don’t realize is that Shiitake is also medicinal, with many health properties like other medicinal mushrooms.
Most notably Shiitake has been shown to help enhance immune function and have anti-tumor properties, lending it as a good adjunct therapy to conventional cancer treatments. It is also shown that it may help in cardiovascular health, gut health, and even have neuroprotective effects.
Shiitake can be consumed in tinctures, powders, or other medicinal products, but Shiitake is also exceptional functional food. Its relative availability, nutritional properties, and delicious flavor make it easy to incorporate this mushroom into your diet.
Natural History Of Shiitake Mushrooms
Shiitake (Lentinula edodes) is a mushroom native to East Asia, where it grows on hardwood trees such as Chinquapin (Castanopsis sp.), Oak (Quercus sp.), and other hardwoods. It usually grows on dead trunks or branches, living within them as a decomposer and feeding on the woody substrate.
The “Shii” in Shiitake is actually the Japanese name for the most common host-tree of the species, The Japanese Chinquapin (Castanopsis cuspidata). The “Take” means mushroom, as is used in Enokitake, Maitake, and Matsutake. Therefore the name could be translated as “Chinquapin Mushroom ”.
Shiitake is a stem and cap mushroom with a chocolate brown cap and light brown stem. The cap is relatively fuzzy with a concentration of fuzz occurring at the margins of the mushroom cap. The cap itself has enclosed margins that unfurl as the mushroom matures. Mature Shiitake mushroom caps grow large and plate-shaped, although it’s rarely ever sold in this form. Younger specimens also have a partial veil that covers the young white gills.
Shiitake fruits in the fall and spring, and may have a unique physical appearance depending on the seasonal conditions. Today it is one of the most widely cultivated mushrooms and is grown in a wide range of climates. The cultivation of Shiitake dates back over 500 years, where it was traditionally cultivated on logs. Today it is largely cultivated on supplemented sawdust mediums.
Shiitake Mushrooms are in the genus Lentinula that contains many delicious and edible relatives. These are often referred to as “Wild Shiitakes” due to their resemblance to the East Asian species. Like any wild mushroom, it is important to know what you are doing before consuming them.
Wild Shiitakes Of The World
Today there are at least 6 different species of Lentinula recognized by science. This number is likely to go up as species continue being studied and described. All of these have similar but distinct morphologies. Their caps are usually brown in coolers with similar fuzz. Always double-check with a professional before consuming mushrooms you are not familiar with.
- New Zealand Shiitake (Lentinula novae-zelandiae)
Distribution: New Zealand - WIld Shiitake (Lentinula boryana).
Distribution: Eastern United States, Mexico, possibly Central America and South America. - American Shitake (Lentinula raphanica)
Distribution: Southeastern United States and the Carribean Islands. Possibly also in Central America. - Australian Shiitake (Lentinula lateritia)
Distribution: Known from eastern Austrailia. - Costa Rican Shittake “Shiitico” (Lentinula aciculospora)
Distribution: Known from the Talamanca Mountains of Costa Rica, likely in Panama too. May also occur in other parts of Costa Rica or Nicaragua.
It is important to consider that these species have not been thoroughly studied like the true Shiitake, Lentinula edodes. Thus the medicinal properties and compounds found within them may vary and may not have the same effects as Shiitake. Even still, these mushrooms are nutritional and very likely contain similar medicinal compounds.
History Of Shiitake Mushrooms
The culinary value of Shiitake has awarded it with deep cultural traditions and recognition. It’s one of the most widely consumed mushrooms and is prepared in many traditional recipes.
The deep culture of Shiitake Mushrooms is no-less evident in the many different names assigned to Shiitake in China. These are not just common names from distinct regions, but they are common names that refer to various classes and forms of Shiitake. There are at least 7 classes of Shiitake, below are a couple of examples.
- “Flower Shiitake” are some of the highest quality shiitake mushrooms, which have innumerable cracks on the surface of the mushroom cap.
- “Winter Shiitake” are medium quality, they are thick but have no cracks.
- “Inch Shiitake” refers to mushrooms whose size is less than one inch.
- “Xiangxin Shiitake” is low quality and grow explosively in hot temperatures.
The fact that Shiitake are delicious and work favorably as a dried mushroom are important reasons why Shiitake is so popular. Dehydration of Shiitake is particularly favorable because they can be easily transported long distances and stored for long periods of time. Unlike other species of mushrooms, Shiitake also works great when dehydrated as its flavor is actually enhanced and it reconstitutes really well.
There are reports that Shiitake Mushrooms may have been present in Chinese culture for thousands of years. It is believed that the culture and prestige surrounding Shiitake mushrooms in Japan may have arrived around the 9th century from Chinese influence. Various accounts suggest that Japan was largely exporting Shiitake to China as early as the 13th century.
There are many folk legends about Shiitake, including legends about the founder of its cultivation method. These are diverse tales of “Wu Sangong aka Wu Yu” which have varying levels of fantasy depending on the version. Shiitake was likely the first mushroom to be cultivated.
The origins of Shiitake mushroom cultivation could date back to as early as the 14th century. There are written records of a rudimentary cultivation technique from this time period in the “Wang Zhen Nong Shu”, a traditional agriculture book. It is possible that elementary techniques may have been employed to promote the growth of Shiitake may have already existed.
The modern log-cultivation technique was developed in 1942 by Japanese scientist Dr.Kisaku More who successfully made the first modern “plug spawn”. This is the method that drastically improved and sped the production of commercial Shiitake production. Today cultivation in grow-kits using a supplemented sawdust medium greatly outnumber the production on logs. Even still, log-grown Shiitake remains a greater value product said to be more delicious and medicinal.
In Traditional Chinese Medicine Shiitake in its pure form was considered to have medicinal properties. It stimulates Qi, invigorates the spleen and stomach, and is said to help with anemia and hypertension.
Today the medicinal properties of Shiitake mushrooms have been scientifically researched. Biologically active beta-glucans have been shown to enhance immune function and have anti-cancer activity. Several other uses such as helping with cholesterol, chronic fatigue, poor blood circulation, upper respiratory disease, and other ailments have been suggested.
Medicinal Properties Of Shiitake Mushrooms
While Shiitake is more popularized as an edible mushroom as opposed to a medicinal, it doesn’t mean that it’s an inferior medicine. In fact, Shiitake has various interesting bioactive compounds that have been shown to help with a wide-range of health issues. A compound called Lentinin derived from Shiitake is of particular interest and has been approved as adjuvant medicine for cancer treatment since the 1980s in China and Japan.
It’s important to consider that Shiitake and medicines derived from it, work best when consumed regularly over long periods of time. Taking Shiitake or other medicinal mushrooms to treat a cold or infectious illness may help, but it’s most effective used as a daily “tonic” that can serve as a preventative. Most importantly, Shiitake works best when used as a supplement to a healthy lifestyle, including healthy diets, exercise routines, and possibly the use of other supplements.
Aside from the active compounds, Shiitake also offers many health benefits in the form of vitamins, minerals, and other key nutrients.
Nutritional Content Of Shiitake Mushrooms
- Minerals: Fe, Mn, Ca, K, Zn, Cd
- Vitamines: D2, B1, B2, B12, E
- Fatty Acids: Linoleic, Palmitic, Tetradecenoic, Oleic, Stearic, Myristic
- Free Sugars: Trehalose, Glycerol, Mannitol, Arabinol, Mannose, Arabinose
- Amino Acids: 18 different amino acids including 7/8 of essential amino acids.
- Other Compounds Of Interest: Beta-glucans such as Lentinin, Alpha-glucans, Eritadenine, and Enzymes
Immune Enhancing Properties Of Shiitake Mushrooms
The immune-enhancing properties of Shiitake mushrooms are largely derived from a special group of Polysaccharides called beta-glucans (Xiaofei, 2014). These are compounds found in all mushrooms and certain plants, although their biological effects can greatly vary depending on the origin. While plant-based beta-glucans, like those found in oats, are part of a healthy diet they are not as medicinal as fungal beta-glucans, such as those found in mushrooms. Within fungi, certain beta-glucans are also more highly regarded for their medicinal properties.
Lentinan is a beta-glucan found within Shiitake mushrooms that has been shown to be particularly effective at stimulating an immune response. They do this by stimulating the production of various immune cells that help ward off any threats such as pathogens, but they also influence your immune-systems communication network through special signaling proteins called Cytokines.
Lentinan is also found in significant quantities within the fungal mycelium. Specially derived varieties of Shiitake are used for the production of high-potency mycelium, but products containing pure mycelium are rare outside of Asia. Mycelium cultivated on grain does have medicinal properties but in much less concentrations than other fungal materials. Check the ingredients of your products to see if it contains grains, if so the products are not recommended.
Anti-Cancer Properties For Shiitake Mushrooms
Shiitake mushrooms have also been shown to have various anti-cancer effects (Meng, 2016). This is largely due to the polysaccharides like Lentinan but is likely due to some other compounds playing a role as well. In fact, Shiitake has been approved as an adjunct therapy to conventional cancer treatment in China and Japan. In this way, Shiitake has been shown to help improve the efficacy, experience, and overall outcome of treatments like chemotherapy and other cancer drugs.
The mechanisms by which Shiitake does this are by having direct toxic effects on cancer via induction of cell death, and through the immune-enhancing properties that help your body fight cancer. When combined with chemotherapy and other medications, Shiitake has been shown to make cancer cells more sensitive to the treatments and thus increase the efficacy of the treatments. Shiitake also reduces the negative side effects of these treatments and helps improve the quality of life for patients.
Research Highlights
Shiitake In Cancer Treatment
- Lentinus edodes mycelial extract prohibited the reduction in natural killer cell activity and leukocyte count in breast cancer patients undergoing cancer treatment. (Nagashima, 2005)
- Breast cancer patients undergoing chemotherapy showed enhancements in immune function and quality of life. (Yamaguchi, 2011)
- Breast cancer patients receiving estrogen-targeted hormone therapy saw improvements after taking mycelial extracts of Shiitake mushrooms. (Suzuki, 2013)
- Improvements in patients receiving adjunct cancer treatments were seen after the addition of extracts from Shiitake mycelium into adjunct cancer therapy was shown to improve the quality of treatment. (Yoshiyuki, 2011)
- A pilot study on cancer patients undergoing chemotherapy suggests that Shiitake extract can decrease adverse effects from chemotherapy in patients with advanced cancer. (Okuno, 2011)
- A study conducted with 47 breast cancer patients showed Shiitake mycelium extracts may be useful in adjuvant therapy for patients receiving chemotherapy. (Nagashima, 2017)
- Combined treatment with Shiitake extracts showed improvement in quality of life and immunological function in cancer patients receiving chemotherapy. (Tanigawa, 2016)
Improving Immune Function
- A study conducted on 52 healthy adults consuming 5 or 10 grams of Shiitake mushroom daily for 4 weeks showed improved immune function via improved immune cell proliferation and activation. (Dai, 2015)
- Lentinan from shiitake upregulates the production of Cytokines, important immune signaling proteins. (Ahn, 2017)
- Polysaccharides isolated from Shiitake mycelium protect mice against salmonellosis via enhanced immune reactions. (Kim, 2014)
- The immune systems of Rainbow trout (Oncorhynchus mykiss) were improved and showed greater disease resistance when fed diets containing Shiitake mushrooms extracts. (Baba, 2015)
- A study conducted on healthy elderly adults showed Shiitake extract had no adverse effects and induced an increase in B-lymphocyte antibodies. (Gaullier, 2011)
Shiitake For Gut Health
- Polysaccharides from Shiitake mushrooms showed beneficial improvement in gut flora of Mice (Xu, 2015)
- Indigestible fibers from Shiitake may have beneficial effects on human gut microbiota (Xue, 2020)
Shiitake To Lower Cholesterol and Improve Heart Health
- Shiitake water extracts modulate the metabolism of cholesterol and thus show potential as a hypocholesterolemic extract. (Ramirez, 2016)
- Shiitake extracts were shown to inhibit one of the main enzymes involved in hypertension and the key enzyme involved in cholesterol metabolism. (Morales, 2018)
Other Potential Benefits Of Shiitake Mushrooms
- Shiitake extracts showed neuroprotective effects from high-fat diets that cause neuroinflammation and cognitive decline in mice. (2012, Pan)
- Shiitake mushroom extract was shown to have extensive anti-microbial activity on bacteria and fungi. (Hearst, 2009)
- Vitamin D2 from Shiitake can help strengthen bones by helping with calcium transport. (Lee, 2008)
- A preliminary study suggests Shiitake may help reduce fatigue in some normal adults. (Kajimaya, 2020)
Are Shiitake Mushrooms Safe?
Shiitake mushrooms are extremely safe and have very little risk of adverse side effects. In rare cases, people have developed skin rashes from eating or handling raw shiitakes. This may be due to the consumption of old specimens or over-soaking mushrooms for several days. Toxicology studies where mice were fed extremely high doses of Shiitake extracts (2g/kg/day) showed no adverse side effects or toxicity (Yoshioka, 2010).
Like all food products, Shiitake cultivated in contaminated environments may bioaccumulate toxic compounds like heavy metals (Wang, 2016). For this reason, it is important to properly source your Shiitake mushrooms from trusted distributors.
How To Consume Shiitake Mushrooms
There are many great ways to incorporate Shiitake mushrooms into your daily life. While consuming Shiitake in food is a great option, you can also consume it in extracts or other medicinal products.
Eating Shiitake Mushrooms
Shiitake mushrooms are a great option as a functional food because they are relatively available and extremely convenient to store when dehydrated. Unlike Reishi, Turkey Tail, and many other medicinal mushrooms Shiitake is also completely edible, digestible, and can likely be found at a local grocery store.
Dehydrated Shiitake can be easily used by rehydrating for 3-4 hours in warm water. Once hydrated mushrooms can be cooked, either in slices or whole. It can be seared in a pan with oil or just incorporated into a soup. They can also be stored post-cooking in the freezer to easily incorporate into the meals. They are great additions to omnivorous, vegetarian, and vegan diets because of their rich flavor and nutrient content. Almost as important as the mushroom itself is the flavorful stock left over after complete rehydration of the mushrooms. This should be cooked and can be used in sauces or soups.
Dose: Studies conducted on healthy adults showed that 5 grams of dried Shiitake, about 3 oz of fresh mushrooms, was enough to cause a positive immune response (Dai, 2015). These servings can be increased depending on your dietary needs.
Choosing A High-Quality Shiitake Product
When it comes to buying medicinal mushroom products it’s important to properly evaluate the quality of it. Not all products are equally as potent and thus effective. This is particularly important if you are hoping to use this mushroom as a supplement to treat a serious illness or disease.
The best way to do this is by buying from a reputable producer who can offer laboratory analysis of their products. These analyses test for the active components known found within the mushroom, as well as for the presence of contamination like heavy metals. This being said, local grassroots producers may also have great products! It is just a matter of analyzing their product and engaging in conversation if you have any doubts.
Other Ways To Consume Shiitake Mushrooms
- Mushroom Powders: Mushroom powders come in various forms and are different from powdered extracts as mentioned below. Mushroom powders are just dehydrated and pulverized mushrooms that include 100% of the raw material. “Activated Powders” can be consumed directly with no need for heating. If your product does not mention that it’s activated or bioavailable you may need to process it via heating. This can simply be done by making a soup or cooking in simmering water for about 5 minutes. Dose: Around 5 grams per day.
- Extracts: Extracts are concentrated forms of Shiitake mushroom. In the case of Shiitake, these largely contain polysaccharides and other water-soluble materials that are separated from the fungal biomass of the mushroom. Some extracts may also remove water-insoluble compounds. These come in various forms and may vary in quality.
- Tinctures: This is one of the most common forms of medicinal Shiitake products. They are usually made via a double extraction process of both water and alcohol. Potency may vary depending on the producer. Dose: About 1-2 droppers per day or 5-10ml.
- Powdered Extracts: These are the most potent forms of medicinal mushroom extracts. The most concentrated ones are made from pure mycelium or fruiting bodies. Dose: 500mg to 1000mg a day
- Coffee, Teas, Soups, Chips and Other Food Items: Many medicinal mushrooms are now incorporated into food items. This may be an easy and convenient way to consume Shiitake mushrooms without having to alter your lifestyle.
Feeling Good and Eating Good with Shiitake
While capsules and extracts can be a great way to get medicinal mushrooms into your life, nothing is more rewarding than eating mushrooms. Shiitake is a great way to get your dose of medicine while consuming something delicious. In reality, you don’t have to stop at Shiitake. Eating mushrooms on a regular basis may improve your health and Shiitake can be one of these staples.
