Some Nutritional and Anti-Stress Aspects of Mushrooms
Some nutritional and anti-stress aspects of mushrooms:

“Nutritionists often misunderstand mushrooms as a food. Although most fresh mushrooms are 90% water, they can vary in their individual moisture content, so it's best to look at them in terms of dry weight. Mushrooms are rich in protein, very low in simple carbohydrates, rich in high molecular weight complex carbohydrates 9polysaccharides), high in antioxidants, and very low in fat. They lack cholesterol, vitamin A, and vitamin C. They are a good source of some B vitamins - riboflavin (B2), niacin (B3), and pantothenic acid (B5) - as well as ergosterols (which upon exposure to ultraviolet light convert to provitamin D2). they're high in dietary fiber, with edible varieties ranging from 20% fiber (by dry weight) for Agaricus species (such as button mushrooms) up to 50% for Pleurotus species (such as the phoenix oyster). Mushrooms are good sources of essential minerals - especially selenium, copper, and potassium - elements important for immune function and for producing antioxidants to reduce free radicals (some mushrooms hyperaccumulate selenium). Mushrooms also contain numerous medicinal compounds such as triterpenoids, glycoproteins, natural antibiotics, enzymes, and enzyme inhibitors that fortify health.”[1]

“From time immemorial, mushrooms have been valued by humankind as a culinary wonder and folk medicine in Oriental practice. The last decade has witnessed the overwhelming interest of western research fraternity in pharmaceutical potential of mushrooms. The chief medicinal uses of mushrooms discovered so far are as anti-oxidant, anti-diabetic, hypocholesterolemic, anti-tumor, anti-cancer, immunomodulatory, anti-allergic, nephroprotective, and anti-microbial agents.”[2]

White button mushrooms are a potential breast cancer chemopreventive agent, as they suppress aromatase activity and estrogen biosynthesis.”[3]

"The white button mushroom suppressed aromatase activity dose dependently. Enzyme kinetics demonstrated mixed inhibition, suggesting the presence of multiple inhibitors or more than one inhibitory mechanism." "These results suggest that diets high in mushrooms may modulate the aromatase activity and function in chemoprevention in postmenopausal women by reducing the in situ production of estrogen." [4]

1. Mycelium Running by Paul Stamet (2005)
2. Recent developments in mushrooms as anti-cancer therapeutics: a review (2012)
3. Anti-aromatase activity of phytochemicals in white button mushrooms (2006)
4. White button mushroom phytochemicals inhibit aromatase activity and breast cancer cell proliferation (2001)