The Understated (and Misunderstood) Health Benefits of Mushroom
Mushrooms aren’t plants. That’s one of the first things you should know. The fact that mushrooms are in an entirely different kingdom from both plants and animals might help you understand why this food is so misunderstood, and why it's understated health benefits often go overlooked.
Mushrooms are a reproductive fungal structure and while that’s not a definition that sounds like something that’s good for you, they’re one of the world’s most potent nutritional powerhouses. In fact, genetically speaking, mushrooms are more closely related to humans than to plants.
Humans have spent thousands of years learning about the countless ways this mysterious food interacts with our health. Here are some of the more surprising benefits that you should know about.
That’s part of the focus of my book Healing Mushrooms: A Practical and Culinary Guide to Using Mushrooms for Whole Body Health.
Immune Defense Secondary Metabolites
Many functional mushrooms, particularly those in the Ganoderma family (which includes reishi), are now being shown to contain organic compounds called secondary metabolites. They're called secondary metabolites because unlike metabolites, they're not directly involved in the normal growth or development of an organism, but they often have species-specific benefits like enabling an animal to resist certain toxic compounds in other organisms with which it interacts. For example, the monarch butterfly can eat milkweed, a plant that’s toxic to other animals, thereby making the butterfly toxic as well and improving its own survival rate.
It’s complicated, but what’s important is that we’re learning more and more about the secondary metabolites in mushrooms. In the reishi and cordyceps mushrooms, secondary metabolites appear to help humans synthesize nerve growth factor (NGF), so we're exploring using them as treatments for neurodegenerative health issues.
Some research is also suggesting that the secondary metabolites in mushrooms may help us to combat antibiotic-resistant superbugs, and certain studies have even suggested that secondary metabolites in Asian mushrooms are responsible for the lower incidences of prostate cancer in many Asian countries.
This is one of the most cutting edge areas of mycology and much of the research are in preliminary stages.
Of all the weight loss techniques you’ve tried, we’re guessing mushrooms probably never made the list. And yet, there are a lot of reasons why mushrooms can improve weight loss.
“Firstly, they are low in calories,” says Leyla Shamayeva, MS, RD, a New York City-based dietitian. “On average, a cup of whole mushrooms provides about 21 calories, three grams of protein, three grams of carbohydrate, one gram of fiber, and practically no fat. This makes them a valuable and filling food for anyone looking to reduce calories without sacrificing satiety too much.”
But even if you prefer to drink your mushrooms, there’s another way that mushrooms may help with weight loss woes: they help to control blood sugar, which helps to control body fat. Put very simply, insulin resistance contributes significantly to weight gain and it’s also what leads to diabetes — it means the body is becoming less sensitive to insulin, which helps to take sugar out of the bloodstream and shuttle it to the organs where it’s needed.
If you’re sensitive to insulin, you don’t need too much of it to move sugar out of the blood. But as you become less sensitive to it (or “insulin resistant”), the body needs more and more insulin to perform this valuable function, and eventually the pancreas gets exhausted making so much insulin and stops being able to do so properly. (That’s when Type 2 diabetes occurs.)
Eating a lot of refined carbohydrates reduces insulin sensitivity, and so does a lack of exercise, a lack of sleep, and many other lifestyle factors. But animal and human studies point toward mushrooms having the ability to decrease blood sugar and improve insulin sensitivity.
On top of that, consumption of mushrooms has been linked to lower levels of inflammation, which can also hamper your insulin resistance and make weight loss more difficult. A 2009 study, for example, found that white button, crimini, maitake, oyster, and shiitake mushrooms all help to stimulate the production of a white blood cell that combats inflammation. (White button mushrooms had the most pronounced effect.)
Can mushrooms really help you control your stress levels? As we mentioned above, they can be effective at attenuating some of the effects of stress. Inflammation and insulin resistance are two of the myriad negative consequences of a stressful lifestyle.
But mushrooms are also a good source of adaptogens, nontoxic substances that protect the body from stress by stabilizing and optimizing its physiological functions.
Cordyceps and reishi mushrooms in particular are known for their adaptogenic properties. Cordyceps is only found in high altitudes (3,800 meters above sea level and over) and it helps stimulate the production of the feel-good hormone dopamine. Reishi, meanwhile, has been used in traditional Chinese medicine for hundreds of years and several studies suggest it may help to reduce anxiety.
Slowly but surely, mushrooms are earning a well-deserved reputation as powerful immunity-supporters. There are a lot of different nutrients present in mushrooms that contribute, through various mechanisms, to an improved immune response and a lower likelihood of contracting illnesses, but let’s start with one of the more surprising reasons: carbs.
“Mushrooms are high in a kind of polysaccharide called beta-glucans, which naturally occur in the cell walls of mushrooms,” says Shamayeva. “Preliminary research showed that beta-glucan stimulates cells that the body uses to defend itself, like macrophages and T-cells. With more research, we may find that certain species could be beneficial for people with compromised immune systems”
More and more research is supporting this assertion, including one review that looked at a whopping sixty-two studies on polysaccharides in mushrooms. It concluded that the various kinds of polysaccharides, including glucans, resulted in statistically significant improvements in immunity among both animals and human subjects.
But beta glucans are just one reason mushrooms have been linked to immune benefits. They also contain another nutrient that you’ll rarely find in lists of must-consume nutrients: copper.
“One cup of mushrooms provides over a third of the recommended daily intake of copper,” says Shamayeva. “Although your body doesn't need much copper, the amount it does require is important for forming collagen — a protein that aids strong bones and connective tissues — making red blood cells, and keeping your immune system running as it should.”
An essential trace mineral, copper has also been linked to improved skin health, with some evidence suggesting that it can speed the healing of wounds and slow the onset of wrinkles. (Which is why it sometimes appears in skin-care supplements.)
A serving of mushrooms also contains a hefty dose of selenium.
“Selenium is a mineral, but it’s one of these minerals that has been looked at for providing antioxidant benefits, so that would be one of the nutrient benefits of eating mushrooms,” says Mary Jo Feeney MS, RD, FADA, a dietitian and consultant for the United States’ Food and Agriculture Industries.
One message that seems pretty clear from the data is that it’s a much better idea to consume selenium in whole food form rather than through pills. Which makes mushrooms a solid bet.
What’s the Best Way to Eat Mushrooms?
In natural health circles, it’s not unusual to hear people swearing that certain cooking methods nullify a food’s health benefits — the fact that heat reduces the amount of Vitamin C is responsible for an awful lot of people believing you should never cook tomatoes. These people neglect to realize than cooking can actually improve other nutritional properties of the tomato, like making the antioxidant lycopene easier to absorb.
Because mushrooms have such an incredible variety of nutrients, there are a lot of different ways to prepare them. Feeney notes that if you’re using Vitamin D-enriched mushrooms, cooking them with a little oil can help it to absorb as it’s a fat-soluble vitamin. Cooking is unlikely to reduce the Vitamin D content, but it may affect the amount of B-vitamins, if that’s a concern.
“Minerals are pretty much retained because they’re more stable than vitamins,” she says. “But high heat and water would certainly affect the B-Vitamins. That’s why a lot of people only add them to soup or stew in the last fifteen to twenty minutes. That way they’re not boiled. But if people eat a variety of foods, they’re not going to be deficient in those B-vitamins anyway — it’s the Vitamin D, potassium, and fiber that Americans need to pay more attention to, and they’re pretty stable throughout the cooking process.”
The Mushroom Council, an American organization dedicated to promoting its consumption, is in the middle of a big push to get more Americans blending mushrooms into their meat dishes. They’ve even got a word for it: Blenditarianism.
“In the US, people are rarely deficient in protein so by using mushrooms in a blend, you can get the benefits of animal protein and dilute some of the negative attributes of animal protein, which may be fat or cholesterol,” says Feeney. “If you can lower your intake of some high fat animal products and substitute mushrooms you sort of get the benefits of both. You get the reduced calories without reduced flavor and you still get the benefits of some of the other nutrients of animal products like iron and zinc.”
She recommends chopping them or putting them in a food processor before adding them to ground meat or stews, but be careful not to liquefy them or it’ll be harder to work with.
“It’s easy to get overwhelmed with the numbers and comparisons, but try not to get caught up in them,” says Shamayeva. “The bottom line is that mushrooms are very nutritious.”