January 20, 2012
For Thousands of Years, Cultures Have Revered The Health Benefits of Mushrooms: So What Happened?
We've become a species that has chosen to forget so much about health. We can whine and complain all we want about how governments and corporations have helped us cater to that mentality, but ultimately we have only ourselves to blame. Mushrooms have long been celebrated as a source of powerful nutrients, having the antioxidant and amino acid profile of some of the healthiest foods, yet we largely ignore this amazing food in the produce aisle. When it comes to health, the almighty mushroom is indeed something to worship.
Mushrooms are the leading source of the essential antioxidant selenium in the produce aisle.
What Are Mushrooms?
Mushrooms are neither plants nor animals; they were reclassified in the 1960’s into the separate Kingdom of Fungi. It is a hidden kingdom. In some ways, mushrooms are more closely related to animals than plants. Just like us, mushrooms take in oxygen for their digestion and metabolism and "exhale" carbon dioxide as a waste product. Fungal proteins are similar in many ways to animal proteins. The part of the fungus that we see is only the “fruit” of the organism. Mushrooms grow from spores, not seeds, and a single mature mushroom will drop as many as 16 billion spores!
There are an estimated 1.5 to 2 million species of fungi on planet Earth, of which only about 80,000 have been properly identified. Theoretically, there are 6 species of fungi for every 1 species of green plants.
Hieroglyphics found in the tombs of the Pharaohs suggest that the ancient Egyptians believed the mushroom to be “the plant of immortality.” The mushroom’s distinct flavor so intoxicated these demi-gods, that they decreed mushrooms to be food for royalty alone, and prohibited any commoner from handling the delicacies.
Some South American Amazon tribes have one word that refers to both meat and mushrooms; they consider mushrooms as equivalent to meat in nutritive value.
In ancient Rome, the
early Romans referred to mushrooms as the “food of the gods.”
The Health Packing Power of Mushrooms
Mushrooms have been successfully used in traditional Chinese medicine for thousands of years to treat many different types of health conditions. Western science and medicine are finally beginning to recognize and utilize some of the medicinally active compounds in mushrooms and elucidate their modes of action.
Mushrooms are considered to be "immuno-modulators". When consumed, bioactive compounds (particularly protein-bound polysaccharides) in mushrooms have strong effects on our immune system. The effect can either be of up-regulation of a weak immune system that is compromised in its ability to fight infections, or down-regulation of a strong but misdirected immune system that is causing auto-immune disorders such as allergies, arthritis, asthma and other disorders. This modulation of immune function in either direction is confounding to Western Medicine and Pharmacological paradigms which are accustomed to medicines that always "push" in one direction.
Just like humans, Mushrooms can produce Vitamin D upon exposure to sunlight and UV radiation. UV light is utilized in the production of these mushrooms. For example, a four-ounce (112 grams) serving of Maitake mushrooms produced by the Hokto-patented methodology contains 85% of the Daily RDA (Recommended Daily Allowance) for Vitamin D. Many people today are deficient in Vitamin D and there is evidence that Vitamin D deficiencies may be linked to cancer and other disease states.
Often grouped with vegetables, mushrooms provide many of the nutritional attributes of produce, as well as attributes more commonly found in meat, beans or grains. Mushrooms are low in calories, fat-free, cholesterol-free and very low in sodium, yet they provide important nutrients, including selenium, potassium, riboflavin, niacin, vitamin D and more.
The focus on the nutritional value of brightly colored fruits and vegetables has unintentionally left mushrooms in the dark. Mushrooms provide a number of nutrients:
- Mushrooms are a good source of B vitamins, including riboflavin, niacin, and pantothenic acid, which help to provide energy by breaking down proteins, fats and carbohydrates. B vitamins also play an important role in the nervous system.
- Pantothenic acid helps with the production of hormones and also plays an important role in the nervous system.
- Riboflavin helps maintain healthy red blood cells.
- Niacin promotes healthy skin and makes sure the digestive and nervous systems function properly.
- Mushrooms are also a source of important minerals:
- Selenium is a mineral that works as an antioxidant to protect body cells from damage that might lead to heart disease, some cancers and other diseases of aging. It also has been found to be important for the immune system and fertility in men. Many foods of animal origin and grains are good sources of selenium, but mushrooms are among the richest sources of selenium in the produce aisle and provide 8-22 mcg per serving. This is good news for vegetarians, whose sources of selenium are limited.
- Ergothioneine is a naturally occurring antioxidant that also may help protect the body’s cells. Mushrooms provide 2.8-4.9 mg of ergothioneine per serving of white, portabella or crimini mushrooms.
- Copper helps make red blood cells, which carry oxygen throughout the body. Copper also helps keep bones and nerves healthy.
- Potassium is an important mineral many people do not get enough of. It aids in the maintenance of normal fluid and mineral balance, which helps control blood pressure. It also plays a role in making sure nerves and muscles, including the heart, function properly. Mushrooms have 98-376 mg of potassium per 84 gram serving, which is 3-11 percent of the Daily Value.
- Beta-glucans, found in numerous mushroom species, have shown marked immunity-stimulating effects, contribute to resistance against allergies and may also participate in physiological processes related to the metabolism of fats and sugars in the human body. The beta-glucans contained in oyster, shiitake and split gill mushrooms are considered to be the most effective.
Benefits of Shiitake Mushrooms
Although immune system support has often received much of the spotlight in shiitake mushroom research, recent study results involving support of the cardiovascular system have caught the attention of many researchers. In particular, recent studies have shown the ability of shiitake mushrooms to help protect us against cardiovascular diseases (including atherosclerosis) by preventing too much immune cell binding to the lining of our blood vessels. In order for immune cells and other materials to bind onto our blood vessel linings, certain protein molecules - called adhesion molecules - must be produced and sent into action. By helping to block the adhesion molecule production process, substances in shiitake mushrooms can help protect our blood vessels.
Shiitake mushrooms have long been recognized as a very good, non-animal food source of iron. But a recent preliminary study has determined that the bioavailability of iron from shiitake mushrooms may be even better than we thought. Although conducted on laboratory animals (female rats) rather than humans, this study found the iron in dried shiitake mushroom to be equally as bioavailable as supplemental iron in the form of ferrous gluconate. (Ferrous gluconate is a very commonly used low-dose iron supplement.) While we don't usually spotlight research on laboratory animals, we found this result to be especially promising for individuals who consume little or no animal products and are often looking for foods that can supply valuable amounts of bioavailable iron.
Shiitake mushrooms can be one of the most sustainable foods in your diet! While the majority of shiitake mushrooms produced worldwide have been grown on sawdust block in a non-natural setting, it is fully possible for shiitake mushrooms to be produced on natural hardwood logs in a forest setting. This approach to shiitake mushroom production is called "forest farming" and it has become an especially popular way of growing shiitake mushrooms in the U.S, where there are now more than 200 shiitake mushroom growers. Unfortunately, forest farming is not a requirement for organic certification of shiitake mushrooms. However, all of the plant crop standards in the National Organics Program regulations apply to shiitake mushroom production, and so the combination of these two features - certified organic shiitake mushrooms that have also been forest farmed - can make a great food choice in terms of sustainable agriculture. Just look for the USDA's organic logo on your shiitake mushrooms to determine if they are certified organic. Then check for information about forest farming on the packaging. If no information is provided, there is a good chance that your shiitake mushrooms were not forest farmed. For this reason, we encourage you to ask your store staff or contact the product manufacturer to determine if your shiitake mushrooms were grown on hardwood logs in a natural forest environment.
No health benefit is better documented for shiitake mushroom than immune support. In fact, the immune support track record for this mushroom is fascinating. On the one hand, numerous studies have shown the ability of whole shiitake mushrooms to help prevent excessive immune system activity. On the other hand, an equal number of studies have shown the ability of shiitake mushrooms to help stimulate immune system responses under certain circumstances. In other words, from a dietary perspective, shiitake mushrooms appear able to enhance immune function in both directions, giving it a boost when needed, and cutting back on its activity when needed. It's important to note that dietary shiitake mushroom intake - unlike intake of medicinal shiitake extracts - has not been shown to be strongly suppressive of the immune system or strongly activating. From our perspective, this finding makes sense. We wouldn't want our everyday foods to strongly suppress or strongly activate any body system. What we would want from our foods is support of body systems under a variety of circumstances - and that is exactly what we get from shiitake mushrooms with respect to our immune system.
One especially interesting area of immune system support involves the impact of shiitake mushrooms on immune cells called macrophages. Among their many important activities, macrophage cells are responsible for identifying and clearing potentially cancerous cells from the body. In order to carry out this task, they need to be "activated" in a particular way. (In more scientific terms, their activated phenotype needs to reflect a higher level of interleukin 1-beta and tumor necrosis factor alpha, and a lower level of interleukin 10.) Shiitake mushrooms are able to help macrophage cells achieve this activated profile so that they can do a better job clearing potentially cancerous cells. Researchers refer to this result as an "anti-cancer immunity" that is enhanced by shiitake mushroom intake.
The cardiovascular benefits of shiitake mushrooms have been documented in three basic areas of research. The first of these areas is cholesterol reduction. d-Eritadenine (also called lentinacin, or lentsine, and sometimes abbreviated as DEA) is one of the most unusual naturally occurring nutrients in shiitake mushrooms that has repeatedly been shown to help lower total blood cholesterol. This nutrient is actually derived from adenine - one of the building blocks (nucleotides) in the mushroom's genetic material (DNA). The beta-glucans in shiitake mushrooms are also very likely to contribute to its cholesterol-lowering impact.
Chronic oxidative stress in our cardiovascular system (ongoing, oxygen-based damage to our blood vessel linings) is a critical factor in the development of clogged arteries (atherosclerosis) and other blood vessel problems. One of the best ways for us to reduce our risk of chronic oxidative stress is consumption of a diet rich in antioxidant nutrients. Shiitake mushrooms are a very good source of three key antioxidant minerals: manganese, selenium, and zinc. They also contain some unusual phytonutrient antioxidants. One of the best studied is ergothioneine (ET). This unique antioxidant is derived from the amino acid histidine, although it's unusual since it contains a sulfur group of molecules that are not present in histidine itself. In studies on ET and our cells' oxidative stress levels, one fascinating finding has been the special benefits of ET for cell components called mitochondria. Mitochondria use oxygen to produce energy for the cell. Heart cells have greater concentrations of mitochondria than most any other cell type in the body. For this reason, researchers believe that ET may be one of the key nutrients from shiitake mushrooms that provide us with cardiovascular support.
Most of the research on shiitake mushrooms and cancer has been conducted on laboratory animals or on individual cells in a laboratory setting and has involved mushroom extracts rather than whole mushrooms in food form. For this reason, our understanding of the anti-cancer benefits of shiitake mushrooms as a whole, natural food is still preliminary. But based on research to date, we believe that adding shiitake mushrooms to your diet is likely to offer you anti-cancer benefits, especially with respect to prevention of prostate cancer, breast cancer, and colon cancer.
The compound, polysaccharopeptide (PSP), which is extracted from the 'turkey tail' mushroom, was found to target prostate cancer stem cells and suppress tumour formation in mice, according to an article written by senior research fellow Dr Patrick Ling in the online journal PLoS ONE, published by the Public Library of Science.
Medicinal extracts from shiitake mushrooms have been studied much more extensively than the whole food itself. In cell and laboratory animal experiments, numerous components of shiitake mushrooms have been show to help block tumor growth, sometimes by triggering programmed cell death (apoptosis) in the cancer cells. These components have been collectively referred to as "anti-tumor mycochemicals" provided by shiitake mushrooms. Researchers have speculated that more than 100 different types of compounds in shiitake mushrooms may work together to accomplish these anti-tumor results. While the unique polysaccharides in shiitake mushrooms were first thought to be its primary anti-cancer compounds, scientists are now convinced that shiitake provides many non-polysaccharide substances that have anti-tumor effects.
The special combination of antioxidants found in shiitake mushrooms together with their highly flexible support for immune system function make them a natural candidate for providing us with protection from a variety of problems involving oxidative stress and immune function. This includes rheumatoid arthritis (RA), an area that has begun to interest shiitake mushroom researchers. Although research in this area is preliminary, we expect to see large-scale human studies confirming the benefits of shiitake mushrooms for prevention of RA.
Medicinal extracts from shiitake mushrooms have well-documented effects on a variety of micro-organisms, including bacteria, fungi, and viruses (including human immunodeficiency virus-1, or HIV-1). While we have yet to see large-scale human studies on whole food intake of shiitake mushrooms and decreased susceptibility to colds, flu or other problems related to unwanted activity of micro-organisms, this is a very likely area for future food research and discovery of health benefits.
Natasha Longo has a master's degree in nutrition and is a certified fitness and nutritional counselor. She has consulted on public health policy and procurement in Canada, Australia, Spain, Ireland, England and Germany.