Polysaccharide kureha (PSK), also referred to as krestin, is actually a kawaratake mushroom extract. In the Japanese language, kawaratake literally denotes 'mushroom on the river bank'. The mushroom kawaratake is found growing extensively in the forest lands in Japan, China and also the United States. The fruiting body of this mushroom is fan-shaped resembling the tail of a turkey. This aspect of the mushroom prompted the English to give it its common name turkey-tail mushroom. The fruiting body of kawaratake mushroom can be found in an assortment of colors, including white, grey, blue or brown. It may be noted here that polysaccharide kureha is the most extensively vended health food in Japan.
This variety of mushroom normally grows on the trunks of trees and is a member of the Basidiomycetes class. Initially, scientists in Japan developed polysaccharide kureha (PSK) for treating cancer and has, subsequently, been also approved as a accompanying treatment for cancers related to the lungs, digestive system and nasopharyngeal - the portion of the pharynx above the roof of the mouth.
Among several other polysaccharides, such as PSP, polysaccharide kureha (PSK) also belongs to a compound present in Coriolus versicolor and known as proteoglycans (also called as beta-glucans, which are macromolecules) and has been well researched. Among its numerous actions, PSK is believed to possess immunostimulant as well as anti-cancer activities. Another action of PSK is to reinstate the immune response by means of creating antibodies as well as cytokines. In addition, polysaccharide kureha augments the damaged anti-tumour actions of the natural killer cells, macrophages, T cells, peripheral blood lymphocytes and neutrophils. PSK also retards the degeneration of the immunocompetence throughout the perioperative period (the time around any surgery). Besides, PSK also slows down the enlargement of residual tumours subsequent to cryoablation - using liquid nitrogen to freeze a specific organ to tremendously low temperatures with a view to eliminate the diseased tissue, counting the cancer cells.
In addition, polysaccharide kureha seems to possess a number of properties that help to perk up the immune system in individual who are undergoing chemotherapy and also has the aptitude to reduce a number of adverse effects of chemotherapy as well as radiation therapy. It is also believed that PSK is a potent antioxidant, an amalgam that obstructs the exploits of activated oxygen molecules, which are also known as free radicals that harm the normal cells. It appears that PSK functions in several stages of the malignant process by means of slowing down binding, motility, invasion as well as metastatic development of the tumour cells in the animal forms of cancer. Additionally, polysaccharide kureha encourages apoptosis or programmed cell death in leukemia, lymphoma as well as pancreatic cells.
As aforementioned, PSK is also a potent antioxidant as well as an immune booster. This health food encloses multifaceted polysaccharides that have shown controlling anti-cancer actions during more than 20 years of experimental use in Japan. PSK has also been employed to augment resistance to skin infections caused by viruses in individuals already having eczema. Altogether more than 200 scientific studies have been conducted involving PSK, which is practically non-hazardous and easily bioavailable when used orally.
The active ingredient present in PSK may also be bought in the form of a coriolus extract. Scientific studies have demonstrated that hale and hearty individuals who took a single dose of one gram of coriolus extract showed considerable progress in cellular immune functioning just within a span of 12 hours. It may be noted that coriolus extract is effectual in treating hepatitis and is currently being examined in the form of a remedy for hepatitis C.
PSK is a protein-bound polysaccharide and has been extensively employed in the traditional Chinese medicine (TCM) since the reign of the Ming Dynasty in China.
During the 1980s, PSK was approved by the Japanese government for curing many different types of cancers. It is interesting to note that in 1984, PSK was positioned 19th on the list of the commercially most successful drugs worldwide having annual sales to the tune of $255 million. It is worth mentioning here that polysaccharide kureha (PSK) is extracted from cultured mycelia belonging to the Coriolus versicolor - a mushroom which is believed to possess anti-microbial, anti-viral as well as anti-tumour attributes.
In Japan, polysaccharide kureha extracts are available for scientific use. In effect, this extract is extensively utilized for cancer immune-therapy in that country. Scientists and physicians in Japan are currently using PSK in the form of a cancer remedy along with surgery, chemotherapy and/ or radiation therapy. The active constituent of PSK may also be administered in the form of a tea or as an oral capsule. A similar product, simply labelled Coriolus versicolor extract is available in the United States. However, the supply of Coriolus versicolor is still limited, while PSK continues to be the best selling remedy for cancer in Japan.
PSK or polysaccharide kureha offers several benefits and some of the condition specific benefits of this medicine are discussed briefly below.
Atherosclerosis: Polysaccharide kureha (PSK) helps in protecting the immune cells present in the arterial wall linings from the effects of the detrimental free radicals. As a result of this action of PSK, the immune cells are stopped from drawing the low-density lipoprotein (LDL) cholesterol, also known as 'bad' cholesterol that accumulates to form plaques, which block the arteries.
Cancer: It is interesting to note that the effectiveness of PSK in treating cancer is identified so extensively in Japan that the sales of this remedy just in one year exceeded 25 per cent of the country's total spending on curing cancer. PSK is particularly useful when it is used in conjunction with regular chemotherapy or radiation therapy. It may be noted that polysaccharide kureha prevents the tumours from spreading by means of immobilizing the enzymes that enable tumour cells to escape from the medium that holds healthy cells in their appropriate places. This action of PSK is particularly helpful in augmenting the efficacy of radiation therapy for treating endometrial cancer.
During a study undertaken with patients in rather advanced stages of cervical and endometrial cancers by scientists at Tokyo's National Cancer Center Hospital, a number of patients were given 3 grams to 6 grams of PSK daily together with radiation therapy, others only received radiation therapy. Following the completion of the treatment with radiation, about 36 per cent of the patients who were given PSK did not have any noticeable cancer cells, while only 11 per cent of the patients who only took radiation did not have any evident cancer cells. In addition, the two-year survival rate among patients who took PSK along with radiation therapy was as high as 94 per cent, while it was 74 per cent for patients who only took radiation therapy. Similarly, the five-year survival rates for patients who took PSK were 79 per cent, while it was 48 per cent for patients who only took radiation therapy.
In fact, physicians have observed an enhancement in the survival rates in patients taking PSK in conjugation with either chemotherapy or radiation therapy for treating lung cancer. In one scientific study involving 185 patients in an advanced stage of lung cancer (stage III), it was found that the five-year survival rate for patients who received PSK as well as radiation therapy surpassed that of the patients who only received radiation therapy by as much as 400 per cent. The findings of another study in which 169 patients participated, showed that PSK was effective in extending the life span of patients who received chemotherapy for seven weeks on an average.
PSK is also beneficial for individuals suffering from colorectal cancer. In one clinical trial, in which 124 patients participated, this medicine has helped to restrict the advancement of the disease as well as enhanced the survival rates. In fact, all the patients were given mitomycin (Mutamycin) as a part of their treatment. It was found that PSK helped to lessen the extent to which the cancer invaded the walls of the intestines and even restrained the spread of this type of cancer to the lymph nodes as well as the blood vessels. In studies undertaken in laboratories, it was found that the use of polysaccharide kureha augmented the efficiency of the chemotherapy agent called 5-fluorouracil (also referred to as S-FU). In effect, PSK decreases the pace at which this type of cancer develops within the cecum, the place where the large intestine has its origin and, at the same time, lessens the rate at which the cancer penetrates the lymphatic system.
Several studies have found that PSK also helps to enhance the efficiency of the T cells, a component of the immune system, in combating colorectal tumours. In addition, it has also been found to be effective in preventing the development of the colon cancer to the liver cells. In a study that was conducted for as many as 18 years, it was found that PSK was effective in reducing the enlargement of colon cancer to the peritoneum - the membrane that forms the inside layer of the intestinal cavity, as well as the lungs in about 60 per cent of the patients who used this medicine.
Polysaccharide kureha is also effective for treating many other forms of cancer. When it is used by leukemia patients, PSK prevents the invasion of healthy tissues by the leukemia cells and, at the same time, it also lessens the possibility of reversion in infancy acute lymphocytic leukemia when chemotherapy is stopped. In the instance of melanoma, PSK lessens the pace of the spread of cancer cells to the lungs and also enhances the efficacy of treatment using chemotherapy in conjugation with cyclophosphamide (Neosar, Cytoxan) as well as interleukin-2 (IL-2) - a chemical of the immune system.
It is worth mentioning here that polysaccharide kureha (PSK) is available in the form of tablets. It is important that you always use this medicine under the direct supervision of a physician or professional healthcare provider.