Cultures around the world have eaten or used mushrooms medicinally for centuries, dating all the way back to ancient Egypt. Legend has it that pharaohs liked their earthy flavor so much, they declared the fungi royalty food and forbid commoners from touching them. Those greedy pharaohs kept the entire supply for themselves.
Fast forward 5,000 years or so to the 19th century, when mushroom production made its way from France (where it began in the 1600s under King Louis XIV) across the Atlantic to America. Today, the billion-dollar industry grows nearly 900 million pounds of mushrooms each year, and we're the second leading mushroom grower in the world behind China, according to the Agricultural Marketing Resource Center.
Estimates vary on the number of edible varieties from 300 to 2,000, but only about 10 are grown commercially, according to the University of Idaho. Americans gobble down white button, oyster and shiitake mushrooms the most, but many varieties hide nutritional superpowers under their white or brown caps and gills.
Whether you eat them raw or cooked (you should cook them, but more on that later), here are some of the health benefits you'll get when you add mushrooms to your diet.
1. They have cancer-fighting properties. A study published in the journal Experimental Biology and Medicine tested five types of mushrooms (maitake, crimini, portabella, oyster and white button) and found that they "significantly suppressed" breast cancer cell growth and reproduction, suggesting "both common and specialty mushrooms may be chemoprotective against breast cancer."
Also, shiitake mushrooms contain lentinan, a type of sugar molecule, according to the Memorial Sloan Kettering Cancer Center, which adds that lentinan may help extend the survival of patients with some cancers when used with chemotherapy. In fact, it has been approved as an adjuvant for stomach cancer in Japan since 1985 since it has anti-tumor effects. "Lentinan does not kill cancer cells directly. Instead, it enhances the immune system, which may aid in slowing the growth of tumors. Lentinan also kills viruses and microbes directly in laboratory studies," according to the cancer center.
Researchers in Japan studied more than 36,000 men for more than a decade and found that those who regularly ate mushrooms had a lower risk of developing prostate cancer. Those who consumed mushrooms three or more times per week had a 17% lower risk than those who ate mushrooms less than once a week. It was especially significant for men 50 or older. The results were published in the International Journal of Cancer.
2. Mushrooms are immunity-boosters. We now know that lentinan can boost your immune system, but it has a helper, too. Beta-glucan is a sugar found in the cells walls of fungi (among other plants) that also helps boost your immune system. Lentinan comes from shiitake mushrooms, but beta-glucan is found in many varieties, namely the common button mushrooms.
In a study, pink oyster mushrooms lowered the amount of bad cholesterol in rats with high cholesterol, though more studies are needed to see if the same results are true for humans. (Photo: socrates471/Shutterstock)
3. They help lower cholesterol. In general, mushrooms are cholesterol free, but they're also a good source of chitin and beta-glucan, which are fibers that lower cholesterol. A study in the International Journal of Medicinal Mushrooms in the International Journal of Medicinal Mushrooms found that pink oyster mushrooms reduced total cholesterol and LDL ("bad" cholesterol) in hypercholesterolemic rats.
Shiitake mushrooms contain a compound that helps the liver process cholesterol and remove it from the blood stream, according to Andrew Weil, M.D., founder and director of the Arizona Center for Integrative Medicine at the University of Arizona Health Sciences Center. And Josh Axe, D.N.M., a best-selling author and nutritionist, writes that mushrooms "contain potent phytonutrients that help keep cells from sticking to blood vessel walls and forming plague buildup, which maintains healthy blood pressure and improves circulation."
4. They're high in B and D vitamins. Mushrooms are one of the few food sources for vitamin D, a fat-soluble vitamin that our bodies can make with exposure to sunlight, because growers are exposing their crops to small amounts of ultraviolet light, WebMD reports. Button mushrooms and criminis in particular are high in vitamin D, but criminis are high in another key vitamin, too: vitamin B12, which is key for vegetarians as it's most often found in animal products. B vitamins are important because they convert food into fuel for our bodies, giving us energy; D vitamins are important because they help our bodies absorb calcium and promote bone growth.
5. Mushrooms have anti-inflammatory powers. Axe says mushrooms contain a powerful antioxidant called ergothioneine, which helps lower inflammation throughout the body. Weil adds that reishi mushrooms in particular, which have been used medicinally in Asia for thousands of years, also have significant anti-inflammatory effects. Multiple studies have shown that reishi mushrooms have multiple health benefits: They fight disease, lower inflammation, suppress allergic responses, reduce tumor growth and more.
Around 200 mushrooms produce psilocybin, which is the naturally occurring compound that makes mushrooms psychedelic. Psilocybe mexicana is believed to be the first mushroom from which psilocybin was extracted in 1959. (Photo: Alan Rockefeller [CC BY-SA 3.0]/Wikimedia Commons)
6. 'Magic' mushrooms may help cancer patients. In a pair of separate clinical trials at Johns Hopkins University School of Medicine and New York University Langone Medical Center, 80 cancer patients suffering from anxiety, depression or a fear of death were given psilocybin, a naturally occurring psychedelic compound found in roughly 200 kinds of mushrooms. About 80% of them experienced "an increase in optimism, a feeling of connection with other people and mystical and spiritual experiences. The effects persisted through the six-month follow-up period," the Washington Post reports. The research, published in the Journal of Psychopharmacology, suggests that psilocybin might be beneficial for people with depression or post-traumatic stress disorder.
7. They could help fight aging. In a study at Penn State, researchers found that mushrooms have high amounts of two antioxidants, ergothioneine and glutathione, which are both associated with anti-aging properties. "What we found is that, without a doubt, mushrooms are [the] highest dietary source of these two antioxidants taken together, and that some types are really packed with both of them," said Robert Beelman, professor emeritus of food science and director of the Penn State Center for Plant and Mushroom Products for Health, in a statement. The amounts of the antioxidants vary by species; the winner "by far" was the wild porcini mushroom, researchers said.
Similarly, a 2019 study found that seniors who ate more than 300 grams of cooked mushrooms a week were half as likely to have mild cognitive impairment. The six-year study — conducted from 2011 to 2017 — collected data from more than 600 seniors over the age of 60 living in Singapore. The researchers looked at ergothioneine as the possible reason for this impact.
Raw vs. cooked
To take advantage of all these health benefits, you really should cook your mushrooms. Here's why:
"The cell walls of mushrooms are tough, making it difficult for the digestive system to get to all the nutrients inside them," Weil writes. In addition, "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," according to WebMD.
A study from Spain found that the healthiest way to cook mushrooms is to microwave or grill them. Unlike with frying or broiling, microwaving mushrooms causes fewer nutrients to be lost during the cooking process. And even though grilling can cause some nutrient loss, using a little oil in the process adds some antioxidants, the researchers found.
Editor's note: This story has been updated since it was originally published in December 2016.