Mushroom health: There are at least 2,000 varieties, but which are best?

By Susan Burke March

The Journal of Wild Mushrooming is a fascinating resource for all things mushrooms. They say there are 10,000 described species in North American alone, but that may represent only a third to a fifth of what’s really out there! In percentages, 50% are inedible, 25% edible but tasteless, 20% will make you sick, and 1% will kill you. That leaves 4% tasty to excellent mushrooms to enjoy! 

As reported in the New York Times, worldwide there are at least 2,000 varieties of edible mushrooms.  All are very low in calories, have a modest amount of fiber, but (in varying amounts), all mushrooms are potent sources of more than a dozen minerals and vitamins, including copper, potassium, magnesium, zinc, and B vitamins including folate.  In addition, mushrooms are rich in antioxidants selenium and glutathione, which may help protect from cell damage and reduce inflammation. Mushrooms are also a rich source of ergothioneine, or ERGO, an antioxidant found in the caps, not the stems. When mushrooms are grown in sunlight or exposed to ultraviolet light they also provide vitamin D.

Yes, mushrooms are good for you, but are they like medicine? On NPR’s Morning Edition, I learned that mushrooms have been used in Eastern medicine for centuries to treat a wide variety of maladies. FantasticFungi.com writes that there are at least 270 species known to have various therapeutic properties.

And now (of course) the dietary supplement industry are getting on the bandwagon, creating  “functional” or “medicinal” mushroom products, with claims such as “preventing cancer” or “stimulating higher brain function” attached.  Yup — you can buy teas, coffees, pills, and potions that promise to “reduce stress” or “jump start your brain.”

Some research has shown that certain mushroom extracts may promote immunity and provide other health benefits:

Lentinula edodes (shitake) mushroom extract is being prescribed in Japan to help prolong the lives of stomach cancer patients undergoing chemotherapy.

Grifola frondosa (maitake or hen-of-the-woods) and scaly wood mushroom extracts may strengthen the immune system of some breast cancer patients.

Hericium erinaceus (lion’s mane or yamabushitake) extract may inhibit growth in cancer cell and protect against neurodegeneration in the lab and in mice.

Ganoderma lucidum (reishi) extract has been studied in mice and may help alter gut bacteria, linked to lower risk for obesity.

Pleurotus ostreatus (oyster) extract may inhibit the growth of breast and colon cancer cells.

The Takeaway

The NPR report says that consuming edible mushrooms is associated with health benefits and is well established, however researchers state that dietary supplements are definitely over-hyped: studies of mushroom extracts are typically in labs and in mice. There’s definitely some promise, but not in the supplement store.

The health benefits of eating mushrooms can’t be separated from the enjoyment of their flavor.  Don’t be afraid to give mushrooms a quick rinse, (no, you won’t ruin them by rinsing them)and use a soft vegetable brush to get rid of any dirt or grit, then pat dry thoroughly and quickly with paper towels.  The secret is not allowing fresh mushrooms to sit in water because they’ll soak it up like a sponge.

My favorite cooking method is to heat a couple of tablespoons of olive oil in a pan over medium heat, add sliced shiitake or portobello mushrooms to the pan and stir.  Add a pinch of salt and any spices such as rosemary or thyme, and continue to cook about 8-10 minutes, stirring frequently.  Once lightly crisped and browned, they’re ready to serve.  Click here for more cooking ideas from OrganicsAuthority.com.

Remember, there’s not enough evidence to support the claims for brain health and cancer prevention from mushroom dietary supplements.  Dietary supplements are not inspected or reviewed to confirm safety and efficacy.  Also, certain mushrooms when taken as extracts or powders can have toxic effects on the liver, increase risk of bleeding in people with certain bleeding disorders. Since there isn’t enough reliable information about taking most dietary supplements if you’re pregnant or breastfeeding, stay on the safe side and avoid using supplements, but enjoy eating some savory mushrooms!

I buy a variety of mushrooms at Supermaxi including portobello and shiitake, and Coral sells mushrooms as well.
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Susan Burke March, a Cuenca expat, is a Registered Dietitian and a Certified Diabetes Educator who specializes in smart solutions for weight loss and diabetes-related weight management. Join the Cuenca Diabetes Support Group to get healthy! Do you have a food, nutrition or health question? Write to her – SusanTheDietitian@gmail.com