Today we talk about Shiitake mushrooms. That does not mean it is the least important. It just presented them as I ran into them.
Shiitake, maitake, and reishi mushrooms (see previous blogs) are widely referred to as “medicinal mushrooms” due to their long history of medical use, particularly in oriental medicine traditions.
The earliest written record of shiitake cultivation is seen in the “Records of Long Quan County” compiled by He Zhan in 1209. The first book on shiitake cultivation in Japan was written by a Japanese horticulturist Satō Chūryō in 1796.
The Japanese cultivated the mushroom by cutting shii trees with axes and placing the logs by trees that were already growing shiitake or contained shiitake spores. Until 1982 only traditional techniques were used to cultivate the mushroom. After that a report rev
ealed processes and opportunities for commercial cultivation in the United States.
Shiitake mushrooms are now widely cultivated all over the world, and contribute about 25% of total yearly production of mushrooms. Commercially, shiitake mushrooms are typically grown in conditions similar to their natural environment on either artificial substrate or hardwood logs, such as oak.
Fresh and dried shiitake have many uses in the East Asian dishes. In Japan, they are served in miso soup, used as the basis for a kind of vegetarian dashi (soup stock) , and as an ingredient in many steamed and simmered dishes. In Chinese cuisine, they are often sautéed in vegetarian dishes. They are a common source of protein in Asia.
Shiitake are also dried and sold as preserved food. These are rehydrated by soaking in water before using. Many Chinese people prefer dried shiitake to fresh, considering that the sun-drying process draws out the umami (5th savory taste) flavor from the dried mushrooms. The stems of shiitake are rarely used primarily because the stems are harder and take longer to cook than the soft fleshy caps.
One type of high grade shiitake is called donko in Japanese and dōnggū in Chinese, literally “winter mushroom”. Another high grade of mushroom is called huāgū in Chinese, literally “flower mushroom”, which has a flower-like cracking pattern on the mushroom’s upper surface. Both of these are produced at lower temperatures.
Today shiitake is very widely used. There is a global industry in shiitake production, with local farms in most western countries in addition to large scale importation from China, Japan, Korea and elsewhere.
Like all mushrooms, shiitakes produce vitamin D2 upon exposure of their internal ergosterol (an essential plant sterol) to Ultraviolet B (UVB) rays from sunlight or broadband UVB fluorescent tubes. While all mushrooms contain ergosterol and have the potential to produce vitamin D2 in such a manner, the transparent white of the shiitake gills permits greater contact of the UVB with ergosterol, and very high D2 values can be achieved with exposure to broadband UVB fluorescent tubes. Shiitake is one of the few natural sources of vegan and kosher Vitamin D.
It’s main polysacchride is lentinan and is an approved drug in Japan used to improve survival rates for those undergoing chemotherapy. It protects chromosomes from being damaged by the chemotherapy and there are no known serious side effects. Entire books in China have been written on all the benefits from taking shiitake. It is often prescribed to be used ‘for those exhausted from overwork’.
In the 1960’s there were studies in Japan showing its effectiveness in lower blood cholesterol by as much as 40%. The amino acid, eritadinine, is the active ingredient, has no side effects and is well assimilated when taken orally.
The only problem encountered with shiitake is that there is a small percentage of people who are allergic to the lentinan and develop a dermatitis.
The median time of onset from ingestion of the mushrooms is typically 24 hours, ranging from 12 hours to 5 days. Most patients completely recover by 3 weeks, with or without treatment (steroids). More cases reported shortly after its discovery were due to eating the raw mushrooms, but several cases have since been reported after eating fully cooked mushrooms.
Link to North American Mycological Association site re: dermatitis: