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Mushrooms as medicine, food, and nutrition

by Timber Press on January 23, 2018

in Food, Natural History

An entire mass of hyphae, or mycelium, visible on a decorticated log.

Which edible mushrooms are the favorites of survivalists? Of chefs? Are humans the only animals that feast on fungi? What kind of preparation makes a mushroom the most nutritious? Learn about using mushrooms as medicine, food, and nutrition from experts and authors of Mushrooms of the Southeast, Todd F. Elliott and Steven L. Stephenson.

The medicinal properties of fungi are underutilized in the United States; not only have we lost traditional knowledge of their uses, but clinical trials of new compounds take decades to be approved for application in a western medical setting. Nevertheless, extensive research supports the application of fungi in both traditional folk medicine and in western clinical medicine. Many compounds currently in use or in clinical trials have been extracted from fungi, including cordycepin (a promising compound for leukemia and other cancer treatments), cyclosporine (an immunosuppressant that makes organ transplants possible), ganoderic acids (a promising group that has shown anticancer properties), lentinan (used in some cancer treatments), penicillin (one of the key early antibiotics), and some statins (a group of medications that are essential for fighting cardiovascular disease). Most of these, along with many other compounds, have been found in fungi that occur in our region.

The ultimate question: How can you access and utilize these and other medicinal compounds from fungi if you are not a chemist? Without a laboratory, you typically cannot use any of these compounds in isolation; in many cases, however, they can be as or more effective in their natural states, which are accessible through home extractions. The best extraction process varies depending on the fungus with which you are working and what compounds are desired. The three most common types of extractions involve hot water, cold water, and alcohol. If you are trying to extract specific compounds, we suggest further reading in a medicinal mushroom or herbal medicine book. The chemical extraction process can be complex and can vary among different fungi.

The jack-o-lantern mushroom, a look-alike to chanterelles, is bioluminescent when fresh. Some wood colonized by certain fungi will also glow at night; this phenomenon is referred to as “foxfire.”

Many of the medicinal polypore fungi in our region have compounds that can positively impact the immune system, and many of these compounds can be accessed simply by soaking the fungi in cold water or by simmering them over low heat. The resulting tea-like beverages are purported to help prevent sickness by optimizing the immune system’s function. We do not claim that any of these compounds will cure particular diseases or conditions, and we encourage anyone interested in utilizing these promising compounds to consult a health professional or the medicinal mushroom literature to learn more.

Many people are at first motivated to learn about fungi so they can find a gourmet meal in nature, and certainly—whether you are a four-star chef, a survivalist, a nature lover, or something in between—learning to identify edible and medicinal mushrooms can be a useful life skill. During the appropriate seasons, mushrooms can provide a substantial quantity of high-quality and nutritious food. This food source is generally underutilized in the Southeast in comparison to other parts of the world. Without a cultural context or the availability of mentors, it can be difficult to learn which mushrooms are safe to eat. In many parts of the world, among cultures with ancient traditions of mushroom hunting, much of the harvesting and identifying of the edible species is even done by children. Here in the United States, traditional mushroom hunting skills have been mostly lost. Sometimes, even seasoned wild food foragers make unfortunate mistakes in identification. One of the best ways to learn mushrooms is to join a regional mushroom club, where you can meet people who know the edible mushrooms in your area.

“Whether you are a four-star chef, a survivalist, a nature lover, or something in between—learning to identify edible and medicinal mushrooms can be a useful life skill.”

Mushrooms are such a large and diverse group of organisms that unfortunately there are no general rules to determine if a mushroom is good to eat or toxic. We can only advise users of this field guide who intend to eat wild mushrooms to take great care and not only learn the edible species but also carefully study and learn all of the look-alikes with which an edible species could be confused. We also suggest getting several field guides to see how different authors differentiate among similar species. Start slowly, learning only one or two edible species at a time and methodically studying them so that all their distinguishing features become apparent. If you are in doubt, throw it out!

Sloppy taxonomy can lead to very sick and occasionally dead mushroom consumers. Keep in mind that there is also the chance of an allergic reaction to a particular species. It is important to eat small quantities and not mix species when you are eating any mushroom for the first time. Just like peanut allergies, fungal reactions can be specific to certain people, and if one person has a reaction to a certain mushroom, it does not mean that this species is toxic or that this person will get sick from eating other mushrooms. Know too that certain species have compounds that can react negatively with alcohol consumption.

Some favorite edible mushrooms can be bioaccumulators, meaning that they absorb heavy metals and other undesirable compounds. Take care not to pick mushrooms for food from potentially toxic environments, such as close to busy roads, golf courses, downstream of parking lots, and in the vicinity of creosote-treated wood. Do not store mushrooms in plastic; if mushrooms are kept in nonpermeable bags or containers, various molds, bacteria, and other potentially harmful secondary organisms can spoil them for human consumption. For short-term storage, it is best to keep mushrooms in paper bags or open containers in a refrigerator; drying, freezing, or canning are good options for long-term storage. Despite the risks just described, many cautious people around the world and in the Southeast eat wild mushrooms for their entire life without any issues.

Caught in the act! This box turtle is a slow and steady mycophagist.

To make mushrooms most nutritious for human consumption, they should be cooked. This even includes the storebought button mushrooms, which are commonly served raw. Some widely eaten mushrooms—morels, for example—can be dangerous if eaten raw. Mushrooms consist primarily of water and chitin but also have many other nutritious components, including amino acids, proteins, chromium, vanadium, and selenium. The specific composition varies by species, so eating a diversity of mushrooms helps to maintain a balanced diet. Fungi can have high levels of vitamin D if exposed to the sun, including vitamins D2, D3, and D4.

Exposure of the gill surface to sunlight after the fruiting bodies have been harvested has been shown to increase available vitamin D in shiitake mushrooms (and likely other mushrooms as well). Most vitamin D3 is derived from animal products or by spending time in the sun; Americans currently have record low levels of vitamin D because people spend less time outside and most animals are raised indoors. If you are concerned about maintaining healthy levels of vitamin D, spend more time out in the forests and fields, first hunting mushrooms and then eating big mushroom dinners!

Humans are not the only animals that feast on fungi. A wide variety of organisms, from microscopic invertebrates to bears, use mushrooms as a food source. Some insects spend the majority of their lives in the center of a mushroom stalk or boring into the fruiting body of a polypore. The majority of the diets of some small rodents are composed of truffles, which have evolved to release pungent aromas once they are mature in order to entice animals to eat them. By digging for below-ground truffles, animals provide an essential ecosystem service of aerating the soil. Once the animal digests the fungi, the fungal spores will be dispersed throughout the forest in the animal’s scat.

It is common to find where squirrels have cached mushrooms in the forks of trees to dry, and if you pay close attention, you may just find a half-eaten deer truffle (Elaphomyces) or a pile of their powdery blackish spores atop a log or at the base of a stump. Many vertebrates in our region have been reported to eat fungi, including armadillos, bears, birds, chipmunks, flying squirrels, foxes, gray squirrels, mice, moles, opossums, rats, red squirrels, shrews, terrestrial turtles, voles, whitetailed deer, wild pigs, and wood rats. Just because an animal is observed eating a fungus does not mean that humans should do it too. Many animals actually consume species of mushrooms that are very toxic to humans.

 

Todd F. Elliott is a freelance naturalist, biologist, and photographer. His research passions are the study of global biodiversity and interrelationships in nature. To read more about his projects, visit toddelliott.weebly.com.

 

 

Steven L. Stephenson, a professor at the University of Arkansas, has collected and studied fungi for more than thirty-five years, and his research program has taken him to all seven continents and every major type of terrestrial ecosystem.

 

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