Mushrooms have been classified as vegetables, but they actually are fungi.  Their cell walls contain chitin* instead of cellulose**, and they lack chloroplasts**.  The class of fungi includes yeasts, molds, and mushrooms.  Fungi can live on dead matter in soil, on other organisms, in air and water.  Common species are shiitake (Lentinus edodes), straw (Volvariella volvacea), oyster (Pleurotus ostreatus), and enoki (Flammulina ostreatus).

China produces 65% of mushrooms and truffles, the European Union produces 24%, and the United States produces 5% of total world production.  Mushrooms grow well in forests, can diversify agriculture, and aid the environment by reducing forest clearing.  They need little water to grow.  “…mushrooms have a small environmental footprint.”  The material in which mushrooms grow can improves soil quality and may be processed into biofuel.

There are at least 22 different edible mushrooms.  White button (WB) mushrooms are 92% water, and about 100 gm. of WB contain 3 gm. protein.  They contain mannitol carbohydrate and fiber.  Oyster and enoki mushrooms are especially high in beta-glucans.

Mushrooms contain small amounts of fat in the form of linoleic acid and conjugated linoleic acid (CLA).  CLA is usually contained in animal flesh.  WB mushrooms contain small amounts of riboflavin, niacin, pantothenic acid, copper, phosphorus, and selenium.  Mushroom B-12 is the same form as found in animals, and is important for vegan diets.  Mushrooms contain vitamin D-2**** which improves 25-hydroxyvitamin blood levels and improves the mineralization of bones.  Vitamin D levels of mushrooms are improved by exposing the mushrooms to sunlight.

Selenium levels of mushrooms depend on soil selenium content and types of mushroom.  Selenium is needed for normal function of glutathione peroxidase, which is an enzyme against lipid peroxides and hydrogen peroxide.  These are associated with tissue damage and inflammation.  Also, the enzyme is needed for sperm motility.

Ergothioneine is an amino acid which contains sulfur, and cannot be made by humans.  Maitake, shiitake, king, and oyster mushrooms are high in ergothioneine.  Also, it is found in liver, kidneys, and bone marrow, black and red beans, oat bran, and some bacteria.  It is found in red blood cells, where is an antioxidant for fatty tissues and protects mitochondria*****.

Mushrooms are beneficial in cognitive problems, cancer, weight management, oral health.  However, research is at an early stage.  The benefit of mushrooms in breast cancer may be due to anti-aromatase activity and reduced estrogen production.  Some benefits of mushrooms may be due to increase in the variety of friendly bacteria in intestines which they promote.  Studies have been done to evaluate the acceptability of mushrooms by people who eat meat in large amounts.  There is evidence that mushrooms may be acceptable to replace some of the meat when they are cooked together.  Mushrooms, also, may be satisfying to people who are on low-salt diets.  Certain mushrooms are toxic, especially to kidneys or the liver, and should not be eaten.  Some wild mushrooms, such as Psilocybe semilanceata, are hallucinogenic.

CONCLUSION:  Mushrooms have been to be highly nutritious and beneficial in specific health problems.  They be increasingly important in agriculture in the future.

NOTES:  *Chitin is a fibrous complex carbohydrate that forms cell walls of mushrooms, as wells as the external skeleton of lobsters, crabs, and shrimp.  This tough tissue is the reason mushrooms are usually cooked to improve the absorption of nutrients.

**Cellulose comes from vegetables.

***Cloroplasts are parts of plant cells containing chlorophyll which take energy from the Sun and convert it to useful energy in plant cells (photosynthesis).

****Vitamin D-2 comes from plants, and is weaker than D-3 from animals.

*****Mitochondria are the areas in cells which produce energy.

Rainbow Grocery sells the following products:  Shiitake, oyster, and enoki mushrooms (and many others), CLA, vitamin D-2 and D-3, many mushroom supplements, and selenium.

Summary #988.

PMID:  24812070.