All species of edible fungi contain different types of nutrients and no two mushrooms of the same species will have exactly the same amount of any given nutrient. They are low in salt, cholesterol, fat and calories. In general, we can say that edible polypores are a good source of protein. Many contain minute but sufficient amounts of B vitamins riboflavin, thiamine, pantothenic acid and niacin. They also contain selenium, potassium and fiber. The fiber in mushrooms comes from the chitin, an indigestible substance that helps keep us regular. Cooking helps break down some of the fiber from chitin which our stomach microbes may find difficult to deal with. We also cook edible mushrooms in order to destroy any toxins or carcinogens they contain. Be aware, however, that not all fungi with toxic compounds can be made safe by cooking. Similarly, some animals can eat poisonous mushrooms with impunity, but we cannot.
Many wild edible mushrooms contain compounds that confer unique flavors and aromas, and some are presumed to have therapeutic properties owing to their micronutrient and antioxidant elements. It is also important to stress that they may also hyper-accumulate heavy metals and toxins at concentrations of at least two orders of magnitude more than edible grains, vegetables and fruits. Studies on this aspect of edible fungi are limited to date, but those available suggest some may be a serious health risk to consumers not cognizant of the location in which they are found or the medium in which they are cultivated. You must do your research and not take chances.
Fungal mycelia create herbicides, fungicides, insecticides and bactericides that enable them to compete with plants, bacteria, insects and other fungi and to provide protection from predation. Defense compounds can be synthesized as needed, while others may take longer to effect results. Their mycelia and fruiting bodies are in constant competition with other organisms for food and space necessary to carry out their specialized ecological roles. We know they communicate with other fungi, bacteria, plants, insects, and animals by manufacturing compounds that enable them to send chemical messages and defend themselves and their symbionts, when required. Many thousands of different secondary metabolites can be produced by fungi depending on the species and their respective or potential predators. Some will deter fungivores with bitter tastes or revolting odors. Others will serve to paralyze or permanently decommission offenders. They can also produce chemical compounds that will attract other organisms to work cooperatively with them. The fact is, we simply do not know enough about all the toxins or beneficial attributes in all fungi, nor do we have a thorough comprehension of their usefulness or dangers to humans.
On their own, fungi are not a complete food, nor a magic pill capable of preventing or curing human diseases. Edible polypores, like edible mushrooms, vegetables, fruits, seeds, nuts, beans and other healthy sources of protein and other required nutrients should be part of any varied diet. All of these ingredients nourish us and contribute to the general health of the individual. When combined with exercise, moderate drinking, and avoidance of smoking and other known threats to health, like all good foods, edible mushrooms and other fungi work to nourish the body’s immune system and assist us in maintaining and living full lives.