A mushroom (or toadstool) is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. Edible mushrooms are the fleshy and edible fruit bodies of several species of macrofungi (fungi which bear fruiting structures that are large enough to be seen with the naked eye). They can appear either below ground (hypogeous) or above ground (epigeous) where they may be picked by hand. Edibility may be defined by criteria that include absence of poisonous effects on humans and desirable taste and aroma.
Edible mushrooms are consumed by humans as comestibles for their nutritional value and they are occasionally consumed for their supposed medicinal value.
The most commonly consumed mushroom in the United States is Agaricus bisporus or the white button mushroom. A. bisporus has two other forms – Crimini or brown mushrooms with a more earthy flavor and firmer texture, and Portabella mushrooms with a large umbrella-shaped cap and meaty flavor.
Andrew Weil, MD, is a longtime mushroom hunter and he seeks them out because of their taste and health benefits. Not all mushrooms are created equal. Weil advises seeking out the more exotic varieties that are becoming increasingly available on supermarket shelves. Here are four that Weil says are particularly good for you:
Shiitake: Animal studies have shown that these flavorful and readily available mushrooms have anti-tumor, cholesterol-lowering, and antiviral properties. Weil recommends fresh and dried shiitakes.
Enoki: These slender, mild-flavored mushrooms appear to have significant anti-cancer and immune-enhancing effects.
Maitake: Also known as ‘hen of the woods,’ these mushrooms may have anti-cancer, antiviral, and immune-enhancing properties. They may also reduce blood pressure and blood sugar, says Weil, who likes to grill maitakes with teriyaki sauce.
Oyster: Less expensive — and less flavorful — than shiitakes, these mushrooms may also provide some protection against cancer.
Weil is less enthusiastic about white, or button, mushrooms, a species of mushroom that also includes Portobellos and criminis.
“Button mushrooms do possess some health benefits, but not the general health benefits found in Asian mushrooms,” Weil says.
Weil also says that these commonly available mushrooms contain natural substances called agaritines, which studies show may increase the risk of tumors in animals. Although there’s no conclusive evidence that agaritines found in mushrooms are harmful to people, Weil likes to play it safe. He advises people to avoid eating large quantities of them.
All told, it is OK to eat button mushrooms in moderation,” Weil says, “but they should always be thoroughly cooked — broiled or grilled is best.” Cooking may break down some of the naturally occurring toxins, he says. In fact, Weil advises against eating any mushrooms – wild or cultivated – raw.
Nutritive Value and health benefits:
1 cup sliced or cut mushrooms contain 15 calories, 0.24gm fat, 2.3gm carbs and 2.16 gm protein.
Mushrooms are a good source of protein as well as antioxidants such as selenium, which helps to prevent cell damage, and copper, a mineral that aids in the production of red blood cells. In fact, mushrooms are the only produce that contains significant amounts of selenium. Portobello mushrooms have more potassium and fewer calories than bananas. Criminis are particularly high in vitamin B12, which is good news for vegetarians because that’s a vitamin more often found in animal products. In general, mushrooms are a decent source of B vitamins. They are also cholesterol free and very low in fat.
White mushrooms are also an increasingly good source of vitamin D because growers are exposing their crops to small amounts of ultraviolet light, which increases their D content dramatically.
When shopping for fresh mushrooms, look for ones that are unspotted and free of slime. The nutritional content of mushrooms can vary greatly depending on where they are grown. Supermarkets source their produce from a variety of sellers, so the mushrooms available this week may be from a different area as those offered last week. Try to shop at farmers markets when possible and buy from the same farmers each time. That way, you’ll know they come from the same soil each time.
Some people may prefer to find their own mushrooms out in the wilderness. Foraging is not without risks — there are, of course, poisonous, even deadly mushrooms. The North American Mycological Association, which has been tracking mushroom poisonings for more than 30 years, receives an average of one report of a human death due to mushrooms each year. Foraging intelligently will keep trouble at bay. Stick to only eating mushrooms that can be identified with 100% certainty — and none should be eaten raw.
It is important that you cook mushrooms thoroughly, and not simply in order to break down small amounts of natural toxins. The cell walls of mushrooms are tough, making it difficult for the digestive system to get to all the nutrients inside them. Mushrooms often contain chemical compounds that can interfere with digestion and nutrient absorption. Sufficient cooking breaks down the tough cell walls, inactivates the anti-digestive elements, and destroys many toxins. It also makes mushrooms taste much better.
Stay tuned for some amazing mushroom recipes!
– Aparna Ramadurai MS, RD
Adapted in part from Dr.Weil’s article.