Shiitake Mushroom, A Gourmet Medicinal Variety

Shiitake mushroom (Lentinus edodes) is a wood-decaying fungus, growing wild on deciduous tree species like chestnut, oak, maple, beech and mulberry. Preferring warm and moist climate zones, shiitake typically flushes in groups rather than as an isolated mycelium species.

Originally cultivated using ancient shiitake growing methods on hardwood logs, the mushroom is now widely propagated for commercial use on natural wood pulp, a rice medium or artificial substrate, and less frequently on cut tree logs.

Shiitake is native to East Asian countries, where it has been wild harvested and extensively cultivated as a common edible mushroom variety utilized for thousands of years.

Most well-known in their native habitat locations in regions of China, Japan and Korea, the mushroom has been a long-revered food source as well as an age-old folk remedy for many ailments from the common cold to inflammatory related conditions.

Pronounced "she-tah-key", the mushroom is one of the most popular cultivated varieties next to Agaricus bisporus or white button mushrooms. Valued as a gourmet mushroom by chefs around the globe for its rich flavor and meaty texture, it is likewise also considered a very medicinal species.

Found fresh or dried in markets worldwide, shiitake is one of the most convenient to use out of all the medicinal mushrooms. While its not quite as therapeutically potent as others, like chaga or coriolus, these types are also not normally as suitable for culinary purposes.

Shiitake is an exquisite tasting mushroom and easy to use in many types of recipes. It is especially beneficial when steamed or heated in soups and stews. This helps to release and concentrate the polysaccharide myco-nutrients into the liquid broth.

For increased medicinal potency, it is also frequently consumed as a dietary supplement or hot water extract, usually produced from either the whole fruiting body, the mycelium biomass or isolated bioactive constituents, as is the case with the lentinan extracts.

1) Lentinan and Other Immune Modulating Polysaccharides
2) May Benefit Chronic Fatigue and Candida Overgrowth
3) Shiitake Benefits in TCM
4) Potential Cholesterol-Lowering Effects
5) Research on Reducing High Blood Pressure
6) Contains the Anti-Inflammatory Ergothioneine

It is important to eat nutritious whole foods and superfoods that keep the immune system functioning optimally so we can prevent major health issues further down the road. Shiitake is an easy food to integrate into the diet on a regular basis to assist in achieving this goal.

Although some of the other medicinal mushrooms have been proven to exhibit stronger immune supporting effects, shiitake is widely available and more familiar to most people.

Shiitake mushroom contains a number of polysaccharides that act as potential immune system modulators with qualities that may help to foster one's defense mechanisms. The most well-known of these myco-constituents is definitely lentinan, but others such as emitanin and KS-2 have also been identified.

LENTINAN, first isolated from Lentinus edodes in 1969, is a beta-glucan polysaccharide that can influence immune response by inducing the body's production of interferon. Interferons are signaling proteins that are released by host cells to defend against and eliminate pathogenic substances.

The word interferon comes from the word "to interfere" as it disrupts the continued growth of harmful viruses, parasites, bacteria or diseased cells. Interferons also stimulate other immune cells and is part of the reason lentinan has been shown to promote NK cell and white blood cell activity.

Research investigating the nutraceutical properties of shiitake mushrooms has been ongoing since at least the 1960's. In this research, lentinan has been the most frequently studied compound found in shiitake or L. edodes mushroom and was actually approved in Japan in 1985 for use as an adjunct in certain therapy treatments.

Lentinan extract has been used in combination with other tonic herbs and mushroom extracts, also known to stimulate white blood cells. The three most common of which include reishi, astragalus root and PSK, the active ingredient in coriolus mushroom.

Both the concentrated shiitake powders and hot water extracts, as well as the simmered fresh mushrooms, contain lentinan and other polysaccharide compounds in high amounts.

The lentinan derived from shiitake has been known to aid in the treatment of other autoimmune disorders including chronic fatigue syndrome. In the book "Shiitake: The Healing Mushroom", Kenneth Jones dedicates an entire chapter to shiitake and its benefits for CFS.

It was discovered over a decade ago that those with chronic fatigue syndrome also appear to have extremely low levels of NK cell activity. In one 2010 study entitled "Biomarkers in chronic fatigue syndrome: evaluation of natural killer cell function", evidence demonstrated that people with chronic fatigue syndrome have decreased function and abnormal activation of NK cells. As we mentioned, shiitake mushroom induces the production of interferon, which can encourage NK cell activity.

Although many of the popular edible mushrooms are not recommended for those with candida overgrowth, shiitake and other medicinal varieties do not encourage the development of fungal yeast strains, but in fact, help to reestablish beneficial microflora through supporting healthy immune responses.

In Traditional Chinese Medicine, shiitake is identified as a food that has an "upward" movement on the "yang" energy of the body and is especially helpful for disorders associated with the lower body region. Often recommended for weak digestive systems, it is classified as having a "sweet flavor" which corresponds to the stomach and spleen meridians and organs.

Referred to as Xiang Gu in Chinese, a word describing its fragrant aroma, it is customarily used as a circulatory system regulator believed to "activate the blood" as well as neutralize toxic influences.

Shiitake mushroom, consumed as a food or supplement extract, has shown to have positive effects on reducing LDL cholesterol due in part to the amino acid constituent called eritadenine. In Japan and China it is also known to be helpful for reducing the risk of stroke as well as high blood pressure.

According to research studies, a compound isolated in the mushroom called eritadenine has shown to have cholesterol-lowering effects when tested on rats consuming a high-fat diet. (*)

Various other scientific investigations indicate that these effects can be achieved by consuming either dried concentrations, extracts or whole shiitake mushroom (caps and stems). All variations are claimed to deliver therapeutic amounts of eritadenine to greater or lesser degrees depending on how they are prepared. (Source) 

The eritadenine is believed to lower cholesterol and lipids by blocking the way it is absorbed into the bloodstream, essentially diverting it to the liver where it can be further processed.

In other more recent studies, low to medium doses of shiitake powder was demonstrated to be a functional supplement for preventing obesity and related metabolic disorders by also inhibiting fat deposition as well as plasma triglycerides.

Shiitake, as well as reishi and maitake, have shown to be beneficial in reducing high blood pressure through its LDL cholesterol-lowering properties. According to the book entitled Shiitake: The Healing Mushroom, "In Japan there are modern-day accounts of high blood pressure normalizing or being substantially lowered from eating eight mushrooms a day for a couple of weeks."

In one study investigating the effects of maitake and shiitake on hypertensive rats, results indicated a decrease in cholesterol levels as well as a reduction in blood pressure.

All forms of shiitake mushroom, powder and extracts contain the anti-inflammatory amino acid "ergothioneine."

This bioactive compound has been proven to be especially effective for reducing the inflammation related to atherosclerotic cardiovascular disease as demonstrated in the 2015 study entitled, "Ergothioneine represses inflammation and dysfunction in human endothelial cells exposed to oxidized low-density lipoprotein."

Shiitake mushrooms are naturally high in certain vitamins, minerals, dietary fiber and amino acids. This includes vitamin D, B vitamins, vitamin K, copper, selenium, pantothenic acid with high amounts of iron in the caps and zinc in the stems. 

According to Nutritional Data, a four mushroom serving (based on a 2000 calorie adult diet) has the highest amounts Recommended Daily Values of:

• Copper - 32% DV
• Selenium - 26% DV
• Pantothenic Acid - 26% DV
  

One of the great things about shiitake is that they are relatively easy to grow indoors on a mushroom growing log or cake. Shiitake's are prolific and inexpensive to cultivate at home with a mushroom growing starter kit.

The shiitake mushroom also makes an excellent log growing variety for incorporating into outdoor permaculture design. They can be used to speed up log decomposition, which will later feed the soil, whilst providing an abundant food source simultaneously.

For more information on how to grow shiitake check out the following books:

• The Essential Guide to Cultivating Mushrooms: Simple and Advanced Techniques for Growing Shiitake
• Mushroom Cultivation: An Illustrated Guide to Growing Your Own Mushrooms at Home
  
• Growing Gourmet and Medicinal Mushrooms

1. Fresh Mushroom Fruiting Body - The whole cultivated, wild or homegrown fresh mushroom.
2. Dried Fruiting Body - The dried whole mushroom, mushroom slices or powder that can be reconstituted or prepared in hot liquids.
3. Hot Water Extracts - These are primarily created from the fruiting body or mycelium biomass; available in powder or capsule form.
4. Standardized Extracts - Lab produced extracts composed of standard ratios of certain active constituents like lentinan. Extracts of the active compounds are mainly sold in Japan.
   

Fresh mushrooms can often be found in the produce sections of most markets usually next to other varieties like cremini, portabella, oyster mushrooms or maitake.

Shiitake is also frequently sold as a dried mushroom which can be handy to have on hand when fresh is unavailable.

Shiitake mushrooms can be eaten raw like other store-bought varieties but can cause digestive disturbance for some individuals such as flatulence and abdominal bloating.

Heating them in simmered water as a liquid broth is a great way to release their polysaccharide-rich nutrients.

They can also be sautéed, steamed or baked with other foods as well as prepared in soups or with grains like our two favorites, quinoa or wild rice.

As another alternative to heating the actual mushroom, marinating and dehydrating shiitake does help to soften the fibers and increases the nutritional value.

The raw mushroom is also more digestible when finely processed into recipes rather than chopped or sliced. These preparation techniques are often used by those adhering to a raw food diet.

The mushroom goes well in miso soup, accompanied with seaweeds, and is delicious when prepared in tempeh recipes.

The best and most medicinally effective way to use this mushroom is to consume the hot water extracts in powder or capsule form. For the greatest health benefits we advise consuming both the mushroom and extracts simultaneously.