The Mushroom – How They Are Developing Their Health Benefits

Mushrooms sitting on a table.
Shiitake mushrooms . Photo by anhnhidesign c/o Pixabay.

The mushroom may become one of our leading healthy foods for all sorts of reasons.

All mushrooms are fungi. They produce spores, similar to pollen or seeds, which allows them to spread or travel by the wind. The rest of the mushroom then matures, typically living in soil or wood. 

There are many different types of mushrooms, some of which are edible including well-known species such as button, shiitake, oyster, horse, porcini and chanterelles. There are, however, many species that are not edible and can in fact cause stomach pains or vomiting if eaten.  Some can be fatal, such as the common death cap mushroom because they contain some of the most toxic poisons known.

Consumption Of Mushrooms

China accounts for 32% of the world’s mushroom production, followed by the U.S. with 16%. The white button mushroom, Agaricus bisporus, is the most widely cultivated species worldwide and the most commonly consumed in the U.S. Its production has increased by approximately 12% over the past decade. If you are interested in growing mushrooms please refer to our page regarding their cultivation.

Consumption of mushrooms in the United States has steadily increased over the past several decades where they consume nearly 4 lb per person per year.

Flavour Impacts

Mushrooms provide many desirable characteristics as food, including the flavor-promoting quality of umami, which stimulates a meaty, savory effect. On a fresh-weight basis, mushrooms contain approximately 90% moisture. They are low in carbohydrates, fat, sodium, and calories. Recently completed research conducted at Johns Hopkins Bloomberg School of Public Health (Cheskin et al., 2007) found that substituting the white button mushroom for meat entrees provided an acceptable lower-calorie alternative without compromising flavor or satiety.

Nutritional benefits 

All types of edible mushrooms contain varying degrees of protein and fibre.

Depending on the species, mushrooms provide numerous vitamins, including the B vitamins (thiamin, riboflavin, niacin, pantothenic acid, and biotin), as well as substantial amounts of potassium, phosphorus, magnesium, copper, and the powerful antioxidant, selenium. This last mineral helps to support the immune system and prevent damage to cells and tissues.

In particular, white button mushrooms are one of the few non-animal sources of vitamin D. When they are growing, whether indoor or outdoor, they are exposed to UV light which substantially increases their concentration of vitamin D2.

Mushrooms are being increasingly researched and used for their important functional, nutritional and general health benefits with different varieties having different medicinal properties. China and Japan have long recognized the nutritional and medicinal properties of various genera and species of mushrooms. Generally, mushrooms are a valuable source of bioactive agents that demonstrate different medicinal properties. In-vitro and in-vivo studies have shown an array of beneficial biological effects (Chang and Buswell, 2003). However, despite their historical usage in traditional chinese medicine, there are no epidemiological studies to support the health benefits of consuming mushrooms.

Ergothionine

Mushrooms serve as one of the best sources of ergothioneine, providing up to 13 mg/85-g serving of specialty mushrooms and up to 5 mg/serving of A. bisporus—white button, crimini (brown button), or portabella. The concentration of ergothioneine in mushrooms is significant. Researchers speculate that consumption of mushrooms because they contain this compound, may provide a strategy for modulating inflammatory responses.

Dubost et al. (2007) at Penn State University recently identified and quantified one particular antioxidant, ergothioneine, that is predominately produced by fungi. Also known as 2-mercapto-L-histidine betaine, ergothioneine is not synthesized in humans. Blood levels of ergothioneine increase after incorporation into the diet. These levels vary among individuals, yet its distribution is similar, predominately in erythrocytes, bone marrow, seminal fluid, and ocular tissue.

In-vitro studies at Penn State suggest that ergothioneine is a strong scavenger of oxidants and chelator of various divalent metallic cations. Other functions of ergothioneine in vivo include retarding lipid peroxidation, protecting erythrocytes, and exhibiting anti-inflammatory properties. Recently, the researchers discovered an ergothioneine transporter highly specific for its physiological substrate ergothioneine.

In addition to quantifying ergothioneine in mushrooms, the Penn State researchers also showed that of the specialty mushrooms, the white button, crimini, and portabello mushrooms provided the highest total antioxidant capacity and total polyphenol content. Based on the total polyphenol analysis, the most commonly consumed mushrooms provide up to 75 mg/serving. However, it is important to remember that these antioxidant assays do not determine biological activity, and the clinical significance of these polyphenols from mushrooms remains to be determined.

Mushroom Polysaccharides

Mushroom polysaccharides, particularly beta-glucans, have been purported to provide immunomodulatory effects, as well as hypocholesterolemic effects. An in-vivo study by Wu et al. (2007) indicated that consumption of white button mushrooms may increase innate immunity, particularly against tumors and viral infections in mice through IFNγ and TNFα production.

Overall, the science behind the health benefits of mushrooms is emerging. Further clinical evidence is needed to determine the exact biological relevance, along with mechanisms of action of the various bioactive agents. The historical and latent evidence suggests that consuming a variety of mushrooms  provides an array of benefits ranging from sensory to health.

Do Mushrooms Help Reduce The Risk Of Losing Memory

One piece of research appears to suggest that might be the case. Older people who eat mushrooms a number of times every week seem less susceptible to developing what is called mild cognitive impairment (M.C.I.). The condition is a precursor of Alzheimer’s disease.

Scientists in Singapore (Yong Loo Lin School of Medicine, National University of Singapore) collected and analysed nutrition and brain performance information from 663 Chinese men and women. At the start of the study, none of the subjects had thinking or memory issues. They conducted one-one-one interviews, checked their diet and dug a bit deeper by finding out what type of mushrooms they were eating. The study is reported in the Journal of Alzheimer’s Disease.

The study involved assessing cognitive function based on detailed and structured interviews and various tests which are designed to examine mental acuity. The study took six years. Ninety people developed M.C.I. in that time.

The researchers accounted and controlled for various factors; socioeconomic, behaviour and health being the three main ones. They also examined the diet of all the participants such as their meat intake, amount of vegetables, fruit and nuts and other types of foods. One significant finding was that those who were consuming less than a single portion (5 ounces) or had up to two portion of mushrooms every week had a 43 percent reduced risk of developing M.C.I. If they ate over two portions, they had 52 percent reduced risk.

The finding suggests consuming mushrooms might help reduce the risk of developing M.C.I. One tentative idea is that the powerful antioxidant ergothionine might be at the heart of this although other components can never be ruled out.

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