Agaricus mushroom is a type of fungus with the scientific name Agaricus blazei from the Agaricaceae family and the Agaricales order, classed in the Basidiomycota phylum. It is one of the gilled mushrooms, which are among the most familiar and commonly encountered. It grows on rotten leaves and is often found at the edges of parks and forests or in the space between them. Agaricus is a saprobe, consuming decaying matter.
Its place of origin is thought to be North America but it can be found all over the world in forests, parks, gardens or any areas with trees. The oldest description of the mushroom and its medicinal properties comes from a medical book dating from the Byzantine Empire. This proves its long history and ancient use in medicine. Today, it can also be found in Europe, Asia, Indochina and Hawaii.
Today, agaricus mushroom is associated with the Brazilian mountain village of Piedade. This village is located approximately one hundred kilometres west of São Paulo, in a mountainous area of the Atlantic rain forest. The natives have used it for a long time for medical purposes and believe it to have numerous benefits, improving health and increasing longevity.
Agaricus tolerates colder areas but likes warm climates. It also enjoys the sun and the best areas are located at the border of forests, outside the tree canopies, in partial sunlight. Its preference for sunny spots is also reflected by the alternative names given to this mushroom, which is also known as "royal sun agaricus" or "the mushroom of the sun".
The color becomes more intense after the mushrooms are dried but is otherwise directly linked with the amount of sunlight and can be anywhere from white to brown, including orange or gold.
When young, the mushroom can have a square shape and a size of about 2-7 cm. This particular shape flattens as the mushroom grows and becomes mature. The stem has a bulbous base and can be very thick and robust. For both eating and medicinal use, the mushroom should be cut before the cap expands and starts releasing spores, since it can become rotten afterwards.
Because of its almond taste, the Agaricus subrufescens variety was nicknamed "the almond mushroom". It was widely cultivated and eaten in the Atlantic areas of the USA in the 19th and early 20th centuries but its cultivation was later abandoned.
New interest in the mushroom was ignited in 1960, after Japanese scientist T. Furumoto collected it in the Brazilian mountain village of Piedade of the Sao Paulo state. He named it "the Piedade mushroom" and sent it to Japan for in-depth research of its medicinal benefits. The death of Furumoto ended all cultivation efforts in Japan but the interest continued in Brazil.
In 1967, Belgian botanist P. Heinemann classified the mushroom and gave it the scientific name Agaricus blazei Murrill. Today, it is cultivated in Brazil and the mushroom has become an important export product, because of its high price. Big quantities are exported to Japan, where cultivation was stopped but the interest remains high.
The most exciting medical use of agaricus mushroom is the great potential as a treatment for cancer. While the precise mechanism hasn't been determined yet, it appears to be effective against several cancer types. It is normally used during chemotherapy, when patients are given agaricus mushroom extract as a parallel treatment.
According to clinical reports, the extract appears to improve the condition of some of the test subjects. The results of a targeted study show that the mushroom extract helps people who suffer from gynecological cancers.
Eating the mushroom has a positive effect on the intestines. During the process of digestion, dangerous chemicals and residues resulted from food accumulate in the guts and can be a health hazard. These are known to lead to brain damage and related problems like amnesia or depression. Agaricus mushroom can clear and detoxify the intestines, eliminating this issue.
According to a study published in Japan, agaricus mushroom can prevent liver failure in severe cases, when the organ is very damaged. This can happen to cancer patients, as a result of aggressive treatment. Japanese researchers have found that mushroom extracts prevent the death of liver tissue in lab rats.
The ability of agaricus mushroom to provide liver regeneration was known since ancient times and it was used to fight hepatitis in tribal medicine. A recent modern study has validated these claims, showing a boost in the liver function of people suffering from hepatitis B.
The agaricus mushroom is used in the treatment of cancer in Japan and Brazil because of its ability to boost the reaction of the immune system. This is mainly caused by the rich content of beta-glucans, which are compounds known to increase immune activity. However, it appears that Agaricus blazei influences the immune system in other ways as well. The fungus contains other polysaccharides such as proteoglucans, which provide the same effect.
This mushroom can also be used as a cure for diabetes, according to preliminary in-vitro and animal tests. One particular clinical test was done on healthy people and the results revealed a decrease of the level of glucose in the blood. Another separate research, only completed on a small scale and on healthy subjects, suggests that agaricus mushroom can lower blood cholesterol levels.
However, it must be said that the main health benefit of Agaricus blazei is the rich content of strong antioxidants. The mushroom could also have an effect on immune cells, stimulating them to generate more cytokines. This was established after research on animals and cellular models.
Agaricus is considered a gourmet delicacy, especially in Japan. It can be quite expensive and it is classed in the same range as the better known maitake and shiitake mushrooms. Agaricus mushroom is highly prized for the texture similar to meat, the sweet almond taste and exquisite flavour. It is normally steamed, in both dried and fresh forms. It can be added as an ingredient to many soups and dishes to provide better flavour and nutritional content.
Like many other medicinal mushrooms, agaricus mushroom is rich in beta glucans, which are a particular type of polysaccharides. It is well-known in the research community that these bioactive compounds have a direct influence on the immune system, increasing the activity of white killer cells. Scientists even believe that polysaccharides might be some of the strongest natural boosts of the immune system, due to their action at a cellular level.
While beta 1-3 glucan is common in many other mushroom species used in medicine, a unique compound named beta 1-6 glucan was isolated from agaricus mushroom. This could be the reason why this fungus is much more potent than other species.
Of course, agaricus mushroom is also rich in other vitamins and minerals, as well as essential amino acids. The ones found in high amounts are calcium, magnesium, zinc, potassium and phosphorus, also vitamin B complex.
One particularly dangerous side effect of agaricus mushroom has been identified. The exact mechanism is unknown but eating too much can lead to severe liver damage. Doctors advise eating the mushroom with caution, no more than 3 times per week, although it's not even known if the liver damage is connected to the amount ingested. It should never be combined with other food or drugs that can damage the liver and people with liver problems are advised to avoid it completely.
Like all other mushrooms, the effects on human health can be unpredictable. It is always better to ask for medical advice before eating it or taking a supplement that contains agaricus mushroom extract. People with known allergies or sensitivity to mushrooms should be especially careful and not risk any consequences to their health.