Are Mushrooms a SuperFood?
Although mushrooms can be found in the produce section of the grocery, they are neither a fruit nor a vegetable. Mushrooms are not technically plants and therefore officially do not contain phytonutrients (plant nutrients.) However, the benefits of mushrooms are huge. They have a great deal of nutritional value, are full of micronutrients, and are considered by some to be among the so called SuperFoods.
There are over 38,000 varieties of mushrooms available with only about 3,000 that are edible and 1400 are recognized as poisonous. A mushroom is a fungus that usually grows above the ground. Photosynthesis does not occur because they are not plants. The texture of a mushroom is best described as fleshy and springy when squeezed lightly. Mushrooms often have a stem, cap and pores under the cap that can all be eaten on the non-poisonous varieties.
Mushrooms are low in carbohydrates and high in fiber. They are a good source of B-vitamins (riboflavin, pantothenic acid, and niacin), iron, and selenium. Mushrooms are naturally low in sodium and high in potassium (a 3 ounce portobello cap has more potassium than a banana). Furthermore, they have essentially no fat and no cholesterol. Interestingly, compounds in mushrooms are actually being studied for their natural anti-cancer effects. Ergothioneine is an antioxidant and anti-inflammatory micronutrient which mushrooms have in very high concentrations. Cooking actually releases this powerful nutrient from the mushroom cells. Mushrooms also have high levels of polyphenols that give them a higher antioxidant level than green pepper and zucchini.
Nutrition is enhanced when a variety of mushrooms is included in your diet along with a healthy mix of other foods high in antioxidants and micronutrients.
Button mushrooms, the popular ones you see in all the grocery stores, have a surprising amount of nutrients including:
In addition, white button mushroom extract has been found to reduce the size of some cancer tumors and slow down the production of some cancer cells. It is most prominently linked to reducing the risk of breast and prostate cancer.
For those who are looking for nutritious weight loss foods to pack into their diets, mushrooms are a less well-known option. Mushrooms are low in calories, carbohydrates, fat and sodium. However, like watermelon, they are very high in water content (80 to 90% water) and fiber which allows them to contribute to weight control.
Most people think bananas are the high potassium food, but it may surprise you to learn that mushrooms out rank bananas on the potassium chart. Potassium helps the body process sodium and lower blood pressure. So people with hypertension or a high risk of stroke can enjoy tremendous health benefits from a regular dose of mushrooms in their diet.
Mushrooms are an excellent source of the antioxidant Selenium which works with vitamin E to protect cells from damaging free radicals. Some studies also indicate that antioxidants are some of the best nutrients for preventing and fighting cancers. Like almonds, mushrooms are becoming more popular for their cancer-fighting and disease protecting properties. Shiitake mushrooms in particular are also high in the beta-glucan Lentinan. Lentinan has been linked with strengthening the immune system and helping combat illnesses that attack the immune system. In addition, mushroom extract has been linked to some treatments for both migraines and mental disorders.
The human metabolism relies on a healthy dose of protein, fiber and vitamin B to keep it functional and robust. Mushrooms rank high in all three of these metabolism-supporting nutrients.
Copper is one of the less talked about minerals that is essential to the body, but that the body can not make on its own. Copper has properties that help protect our cardiovascular system, and just one small serving of mushrooms contains more than 20 percent of the copper we need daily.
With our fast-paced lifestyles and the highly processed foods we may frequently find ourselves eating in haste, the magnesium, potassium, phosphorus and selenium nutrients found in a single dish of mushrooms can really make up for some of the deficiencies we struggle to combat in our diets.
Some experts suggest that even edible, everyday mushrooms should be cooked. Dr. Andrew Weil claims that all mushrooms are essentially indigestible if eaten raw because of their tough cell walls, and that to release their nutrients, they must be cooked. More importantly, he says, certain mushrooms contain small amounts of toxins, including a compound considered carcinogenic, which is destroyed through cooking because these compounds are not heat stable.
The compound in question, agaratine, is most commonly found in the mushrooms belonging to the genus Agaricus. This includes the common white or button mushroom—your everyday supermarket variety that is commonly found raw at restaurant salad bars:
A study in the 1990s found that agaratine has a carcinogenic effect in the bladder of rats, while another study found cell mutation effects in mice that could lead to cancer. However, extrapolating from the study, the risk was found to be quite low—a lifetime cumulative cancer risk of about two cases per 100,000 lives. Since agaratine is destroyed through cooking, the cautious consumer may wish to sauté, bake, or broil their mushrooms—the common white ones, in particular—just to be safe.
In conclusion it may be stated that mushrooms have a very positive effect on our health. Listed below are a few things that have been discovered about mushrooms:
reduces cardiovascular disease by lowering blood pressure and cholesterol
reduces insulin resistance which increases insulin sensitivity
blocks the growth of some cancer tumors
boosts the immune system
lowers toxic levels of estrogen hormone
strong antioxidant properties
low in sodium, calories and fat
high in fiber
So eat your mushrooms—but for maximum nutritional value (and to get rid of any toxicity), you might want to give them some light cooking first!
Paul R. Block, MD, FACP, FCCP