CHAPTER FIVE
Beta Glucan All-Star
ONE OF THE MOST exciting medicinal mushrooms is a relative newcomer, Agaricus blazei. Many scientists believe that the beta glucan in this mushroom is more potent than that of other mushrooms. Forty years ago, the medicinal properties of the mushroom were known only to a few thousand villagers in Brazil, but since the world discovered the mushroom, its reputation has spread far and wide. Agaricus blazei has shown real promise as an immunomodulator and a defense against tumors.
Agaricus blazei does not have as colorful a past as some of the other mushrooms described in this book. Instead of the exotic East, the origins of Agaricus blazei can be traced to a small mountain town in Brazil called Piedade located some 120 miles (200 km) southeast of São Paulo. For centuries, the inhabitants of the town and its environs have savored a mushroom that they call Cogumelo de Deus (“the mushroom of God”), Cogumelo do Sol (“the sun mushroom”), Cogumelo Princesa (“the princess mushroom”), or Cogumelo da Vida (“the mushroom of life”). In 1965, two events transpired to bring the rare mushroom to the attention of the world. In the summer of that year, a Brazilian farmer of Japanese descent named Takahisa Furumoto was roaming the mountains beside Piedade when he noticed an unfamiliar but tasty mushroom. The mushroom appeared to be of the Agaricus family. Furumoto sent spores of the mushroom to Inosuke Iwade of the Iwade Research Institute of Mycology in Japan. To learn more about the mushroom, Iwade, a scholar in the field of mushroom cultivation, attempted to grow the mushroom in his laboratory, an attempt that would take nearly a decade.
Meanwhile, back in Piedade, a group of scientists led by Dr. W.J. Cinden of Pennsylvania State University had begun their own investigation into the unknown Agaricus mushroom. Cinden and his colleagues had come to Piedade to find out why the inhabitants of the town had low rates of geriatric disease and a reputation for longevity. He concluded that the people of Piedade enjoy long life because they eat an unusual mushroom of the Agaricus family as part of their diet. Dr. Cinden published his findings in Science magazine and presented his conclusions at several conferences. Word about the unusual mushroom from Brazil began to spread.
After Inosuke Iwade at last managed to cultivate samples of the Agaricus mushroom in his laboratory in Japan, he noticed that this Agaricus was longer and thicker than others in the Agaricus family. The gills took longer than usual to turn black. The mushroom emitted a strong aromatic odor and the root was sweet and delicious. Did he have a new species on his hands? Iwade submitted a sample of the mushroom to a Belgian taxonomist named Heinemann, who deemed the mushroom a new species of Agaricus. He named it Agaricus blazei Murrill because, as it turned out, the mushroom had already been documented and described by the noted American mycologist W.A. Murrill. According to the story, Murrill found the mushroom on a lawn in Gainesville, Florida. (As a staff member of the New York Botanical Garden in 1904, Murrill identified the infamous Chestnut blight, Endothia parasitica, the fungus that all but destroyed the American chestnut tree, “queen of the Eastern forest,” in the eastern United States. From the 1930s until his death in 1957, Murrill discovered over 650 species of fungi in Florida.)
Agaricus blazei grows in the southeastern United States, although not as prolifically as in South America. In Japan, the commercial name of the mushroom is Himematsutake; its common name is Kawariharatake. It is also known by these names: Murrill’s agaricus, Royal sun agaricus, and, less frequently, songrong and almond portobello.
Agaricus mushrooms are quite common throughout the world. The “button mushroom” (Agaricus bisporus) found in American supermarkets is an example of an Agaricus mushroom. There are about thirty species of Agaricus. The mushrooms range in color from off-white to light brown. The caps emerge as round “buttons” from the soil and grow in size from one to twelve inches across, depending on the species. At first the gills are off-white, but within three days they turn pink, purple, and then black. Chances are, if you see a mushroom growing on a lawn or pasture, it is an Agaricus mushroom.
Agaricus blazei, however, does not grow as wantonly as most Agaricus mushrooms. Where other species of mushroom prefer shade and dampness, Agaricus blazei favors the humid, hot-house environment of its native Brazil. The mushroom grows only in the hot summer months. It may die if temperatures drop too low. In the Piedade region, temperatures range from 95 degrees (35C) during the day to 72 degrees (22.2C) at night, and the land receives a good dousing by tropical rain in the afternoon or early evening. According to a story, one reason that Agaricus blazei thrives in the region has to do with the number of wild horses found there. Horse manure, the story goes, contributes to the fertility and unique composition of the soil.
Attempts to cultivate the mushroom with biotechnological assistance did not begin producing stable yields until the 1990s. Agaricus blazei’s tropical native environment is very difficult to replicate. The mushroom is now being cultivated in Japan, Korea, the United States, Denmark, Holland, and Brazil. Sugarcane bagasse was found to be the best culture bed material for growing the mushroom. A few years ago, when the demand for Agaricus blazei skyrocketed and its price rose accordingly, the mushroom all but disappeared from the Piedade region of Brazil, according to some reports. (Another story had it that horse manure never stayed on the ground long in Piedade—it was needed by farmers for the cultivation of Agaricus blazei.)
As Chapter Two of this book explains, beta glucan is a kind of polysaccharide chain molecule that is found in medicinal mushrooms. Beta glucan is known to help make the immune system more alert and balanced. Although no one knows for certain how beta glucan does its work, it is believed that beta glucan fools the immune system into thinking it is being attacked by a bacterium. The immune system, accordingly, marshals its defenses, and the result is a stronger immune system.
Some scientists believe that Agaricus blazei contains the highest level of beta glucan of any mushroom. Many studies seem to show that the beta glucan in Agaricus blazei is especially advantageous against tumor cells. Due to its low molecular weight, beta glucan from Agaricus blazei can be absorbed into the body more easily than beta glucan from other mushrooms. This is believed to make it more effective.
Clinical interest in Agaricus blazei began in earnest when a study showing antitumor activity by the mushroom was presented at the general convention of the Japanese Cancer Association in 1980. In the study, Agaricus blazei was reported to have higher levels of beta glucan than the maitake (described in Chapter Six of this book), shiitake (Chapter Ten), or reishi mushroom (Chapter Three).
In 1995, Dr. Mamdooh Ghoneum of UCLA Medical Center, speaking at the Ninth World Immunology Congress, declared that the Agaricus blazei mushroom increases the total number of all immune cells within the body and also makes individual natural killer cells more powerful. This was a startling announcement in many ways, because it was the first time that a prominent American researcher had sung the praises of Agaricus blazei. Also in 1995, at the Seventh General Meeting of the Technical Discussion Group for Fungi held in Nara, Japan, Dr. Takashi Mizuno, who has studied Agaricus blazei for many years, commented on a beta glucan he isolated in the mushroom, “The glucan-protein complex was the first case of an antitumor compound found in an edible mushroom.”
Agaricus blazei has indeed generated a lot of interest in the scientific community. Following are recent studies concerning the medicinal qualities of the mushroom.
Agaricus Blazej and Cancer
Cancer is a complex immune-associated disease that can affect any organ or system of the body. It is caused by uncontrolled cell growth resulting from a genetic defect or cellular damage due to radiation or toxins in the environment. Although many advances have been made in the field of cancer research, there is still much to be done. Unfortunately, treatments such as radiation and chemotherapy can be as debilitating to the patients as the cancer itself. Research indicates that traditional therapy used in combination with alternative therapies may help cancer patients.
Scientists at Kobe Pharmaceutical University in Japan decided to test the effects of Agaricus blazei on cancer. They injected a water-soluble fraction from Agaricus blazei into one group of cancerous mice and a saline solution into another group. Results of the experiment showed an increase in lymphocyte T cells, the immune system cells that are involved in protecting humans against cancer, in the Agaricus blazei group. As Chapter Two of this book explains, lymphocytes are carried in the lymph, the fluid that circulates in the lymphatic system.
The scientists concluded that beta glucan from Agaricus blazei may be an effective preventative against cancer. In other words, if your family is predisposed to getting breast cancer or prostate cancer, taking Agaricus blazei, especially early in life, may be a good idea, as it may keep you from developing the cancer.
Agaricus Blazej and Tumors
Some herbal extracts, including those from mushrooms, are known to attack tumors without doing any damage to normal tissue. In 1999, a group of scientists from Japan extracted substances from Agaricus blazei in order to monitor their effect on tumors in laboratory mice. The scientists injected the tumor with the Agaricus blazei substances and noticed a marked inhibition in the tumor in the right flank where they made the injection and in the left flank as well. One of the components of the Agaricus blazei extract was a polysaccharide complex with a low molecular weight called Alpha-1, 4-Glucan-Beta, 6-Glucan. The scientists reported that this polysaccharide had the strongest antitumor effect. It was able to selectively kill tumor cells without affecting normal cells.
Interestingly, the experiment also showed the possible activation of granulocytes. Granulocytes contain granules with potent chemicals that kill micro-organisms and playa role in controlling acute inflammatory reactions. The scientists speculated that both flanks of the tumor were inhibited because the granulocytes were able to migrate to the left flank, the side of the tumor where the injection was not made. It seems that the Agaricus blazei polysaccharide examined in the study not only inhibits tumors from growing, but it also stimulates the migration of the white blood cells that scavenge and kill malignant cells.
The same group of Japanese scientists conducted a similar experiment with Agaricus blazei extracts. This time, the noninjected side of the tumor also regressed, but the scientists noted that it regressed due to the activation of natural killer cells. What’s more, the extract induced apoptosis in the malignant cells. In effect, apoptosis refers to cells committing suicide. Again, in this experiment, the scientists observed that the Agaricus blazei extract killed tumor cells, but not healthy ones. Apoptosis was seen only in the malignant cells.
Another Agaricus Blazei Cancer Study
To immobilize or neutralize a malignant cell is not enough. The body needs to rid itself of the cell by making it burst and killing it. One way that the body destroys cells is byway of complement, a series of proteins that are produced in the liver. The activation of the complement cascade causes holes to be punched in the membrane of the targeted cell and its inside to ooze out. The most active component of complement is called C3. Complement also attracts and stimulates macrophages to eat the malignant cells. As Chapter Two explains, macrophages are the giant white blood cells that eat and destroy malignant cells.
Recently, scientists at Mie University School of Medicine in Japan conducted experiments to gauge the effect of Agaricus blazei on complement proteins made in the liver. Specifically, they wanted to examine the activity of the C3 complement. The scientists implanted sarcoma tumors in mice and fed the mice a polysaccharide that they cultured from the mycelia of Agaricus blazei. The polysaccharide succeeded in activating macrophages in the mice and activating C3 protein. From this, the scientists concluded that Agaricus blazei could well be an aid in fighting the spread of malignant cancer cells in the body.