Mushrooms are members of the fungi kingdom and are not the same as plants. In fact, fungi are more closely related to animals than plants; like us, they don’t photosynthesize. The compound that provides structure to fungi’s cell walls is chitin, which makes up the exoskeletons of lobsters and ants and the scales of fish.

Mushrooms are the fruiting bodies of fungi in the same way that a pear is the fruiting body of a pear tree. They’re made up of three parts: the stipe (stem), the pileus (cap), and the lamellae (gills). The “seeds” of the mushroom “fruit” are its spores, which form a network of microscopic rooting threads called mycelium. This is a mass of thread-like branches that mushrooms use to decompose nearby plant material in order to extract nutrients. A mycelium can live for many years, communicating with plants and sending up its annual crop of mushrooms.

The mycelium can be small and compact or can span underground over thousands of acres with mushrooms popping up out of the ground sporadically or in clusters. The world’s largest organism is thought to be a mycelium network belonging to a mushroom technically called Armillaria ostoyae, commonly known as the honey mushroom, found in Malheur National Forest, Oregon. How enormous is it? This mushroom’s mycelium network covers two square miles and is around 8,650 years old. So if you ever get tired of knock-knock jokes, you can try this riddle: “What’s two and a half miles across, 8,650 years old, and lives in Oregon?”

In addition to white button mushrooms, which are readily available and typically less expensive than other varieties partly because it’s possible to cultivate them commercially on a giant scale, there are many other kinds. Button, brown cremini and portobello mushrooms are the same variety, just aged longer or allowed to grow bigger (buttons are the youngsters, brown cremini are the teens, and portobello are the grown-ups).

Other increasingly common mushrooms include oyster, shiitake, enoki, lion’s mane, turkey tail, hen-of-the-woods, beech, chanterelle, porcini, and morel.

You’ll find different kinds and ratios of nutrients in different mushroom varieties, so for this section, I’ll focus exclusively on that surprising superfood, white button mushrooms (since they’re generally the most affordable of the fungi). They’re low calorie and high in protein. They’re loaded with antioxidants — beating out such formidable plant foods as tomatoes, green peppers, pumpkins, zucchini, carrots, and green beans — and even topping more expensive shiitake and oyster mushrooms.

Button mushrooms are also packed with vitamins and minerals like B vitamins, selenium, potassium, and copper. They contain two types of important dietary fibers, beta-glucans and chitin. Interestingly, when mushrooms are exposed to sunlight while growing, they are one of the few natural dietary sources of vitamin D.

OK, this is where I have to remind myself that this is just a chapter, not an entire book. Because science has discovered over 200 conditions affecting human health that can be treated to some extent with mushrooms, and at least 100 mechanisms by which mushrooms support our health. So what follows is a very short list.

Mushrooms are a gut-friendly food, offering the good bacteria in your gut lots of prebiotic fiber. They’ve also been found to balance the microbiome’s beneficial bacteria, such as acidophilus and Bifidobacterium. 

 

One of the amino acids found in mushrooms, ergothioneine, has been associated with a lower risk of heart disease. In a study concluded in 2019 (started in 1998), researchers measured 112 different aspects of blood chemistry of over 3,000 people who didn’t have heart disease at the start of the study, and then followed them for an average of 21 years. The blood marker that best predicted continued freedom from heart disease was ergothioneine. The researchers concluded that a diet high in ergothioneine-rich foods was a good way to obtain that protection.

Several studies have shown that eating mushrooms can help protect your brain. In 2010, researchers found that Norwegians in their 70s who ate mushrooms at least three times a week had a 19% lower risk of developing dementia. Seven years later, Japanese researchers analyzed a 2006 population study and discovered a linear relationship between mushroom consumption and lower incidences of dementia. And this relationship held even when eliminating other factors that might also support brain health, like consumption of fruits and vegetables and educational level attained.

In 2017, a research team in Singapore found that eating more mushrooms lowered the risk of mild cognitive decline, which brain researchers see as an intermediate step on the way to full-blown dementia.

Roughly one in nine women will develop breast cancer during her lifetime. While early detection and medical advances have improved survival rates, it’s still a terrifying diagnosis for many people. And early detection is not the same as prevention. What if there were a food that could actually reduce a woman’s risk of developing this dreaded disease?

Can you picture a white button mushroom? Now imagine cutting that single mushroom in half, and then cooking and eating it. And having just that much mushroom every day.

Congratulations! In that modest thought experiment, you just cut your risk of developing breast cancer by two thirds. You read that right — a study of over 2,000 Chinese women found that eating just a third of an ounce of (about a half of one) mushroom daily cut the risk of breast cancer by 64%.

Men shouldn’t feel left out; white button mushrooms have been shown to lower blood levels of prostate-specific antigen (PSA), a marker associated with the development of prostate cancer. They may do this by suppressing androgen receptors, thereby slowing the growth of cancer cells.

Mushrooms enhance the ability of dendritic cells, found in bone marrow, to produce T cells that kill disease-causing pathogens. They are also a rich source of compounds called beta-glucans, which activate white blood cells to help fight off foreign substances and diseases. 

The more fiber you eat, the lower your chances of developing type 2 diabetes, according to a giant meta-analysis published in The Lancet in early 2019. And mushrooms are one of the best sources of fiber out there. In particular, they contain lots of prebiotic fiber, which is yummy food for the “good” gut bacteria that do incredibly important jobs in your body. And a healthy gut is one of the best defenses against literally dozens of maladies including type 2 diabetes and digestive disorders such as irritable bowel syndrome.

Eating more fiber is one of the most reliable ways to lose excess weight and keep it off. One cause of obesity is the modern industrialized diet, which is largely made up of animal products that contain no fiber and processed plant foods that have had the fiber removed. One of fiber’s important functions is to make us feel full, so we stop eating before downing more calories than we need.

In one study, researchers asked some people to substitute mushrooms for meat in some of their recipes. Those who consumed at least 2¼ ounces of mushrooms per day (that’s roughly 4 medium button mushrooms) experienced significantly more weight loss than those who didn’t. They also ended up with a lower body mass index and a smaller waist circumference after one year.

Mushrooms are a great substitute for meat in lots of dishes, thanks both to their strong umami flavor and meaty texture. 

First, a word of caution: some edible mushrooms may contain a slightly toxic compound called agaratine. The good news is, agaratine breaks down when exposed to heat. So mushrooms should be cooked, not eaten raw.

But that’s all right, because cooked mushrooms are delicious, and they’re very easy to prepare in all sorts of ways. They’re wonderful in stir-fries and casseroles. You can marinate and grill them, or slice them for a pizza topping. Mushroom soup is a classic; with an immersion blender, you can make it thick and comforting — a steaming anchor for a simple winter peasant meal.

You can also use mushrooms as a basis for vegetarian burgers and other meat analogues. 

However you choose to include mushrooms in your diet on a regular basis, your taste buds, your tummy, and your body as a whole will thank you! ❧

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