Medicinal mushrooms are mushrooms that are used as medicine. They have been used to treat infection for hundreds of years, mostly in Asia. Today, medicinal mushrooms are also used to treat lung diseases and cancer. For more than 30 years, medicinal mushrooms have been approved as an addition to standard cancer treatments in Japan and China. In these countries, mushrooms have been used safely for a long time, either alone or combined with radiation or chemotherapy.

In Asia, there are more than 100 types of mushrooms used to treat cancer. Some of the more common ones are Ganoderma lucidum (reishi), Trametes versicolor or Coriolus versicolor (turkey tail), Lentinus edodes (shiitake), and Grifola frondosa (maitake).

Mushrooms are being studied to find out how they affect the immune system and if they stop or slow the growth of tumors or kill tumor cells. It is thought that certain chemical compounds, such as polysaccharides (beta-glucans) in turkey tail mushrooms, strengthen the immune system to fight cancer.

Medicinal mushrooms, also known as mycomedicinals, and mushroom-derived polysaccharide preparations have been studied as immune modulators and adjuvant agents in cancer treatment. Mycomedicinals have been found to modify tumor response and improve immune function, primarily in patients with solid tumors. Mushrooms contain biologically active polysaccharides in their fruit bodies, or mycelia. The -glucans of mushrooms resemble bacterial cell walls and complex with complement on macrophages to activate an immune response triggering the release of various cytokines that are active in tumor inhibition. The following describes several mycomedicinals and the research related to their use.

Mushrooms have a cell wall made of chitin, which is the same fiber contained in the shell of a lobster. Chitin is indigestible by humans but contains bioactive -glucans and polysaccharides. Different extraction methods result in varied antitumor properties exhibited by the mushroom. Hot water extraction breaks down the chitinous cell walls and releases the bioactive polysaccharide structurally intact and undamaged. This is performed by simmering or boiling the mushroom in water for 20 to 120 minutes. Alcohol extraction is another common method that is used.

Coriolus (trametes) Versicolor (Turkey Tail)

Over 400 in vitro and animal studies of Coriolus versicolor extract have demonstrated that it stimulates the immune system, inhibits the growth of cancer cells, and acts as a strong antioxidant. Polysaccharide krestin (PSK) and polysaccharide peptide (PSP) are bioactive extracts of C. versicolor. In Japan, PSK is an anticancer drug currently used as an adjuvant treatment with surgery, chemotherapy, and radiation for esophageal, lung, stomach, breast, and colon cancer. PSP was discovered more recently and has been studied mainly in China. PSP activates the immune system by increasing production of cytokines and chemokines, stimulating dendritic and T-cell infiltration into tumors, and reducing chemotherapy side effects. Studies of PSK have found increased activity against trastuzumab-mediated breast cancer and docetaxel-induced prostate cancer suppression in mice.

A systematic review and meta-analysis of 13 clinical trials analyzing survival in cancer patients taking 1 to 3.6 gm of PSK or PSP per day for 1 to 36 months found that those taking C. versicolor had a 9% absolute reduction in 5-year mortality, resulting in one additional patient alive for every 11 patients treated. The effects were more evident in patients with breast, gastric, or colorectal cancer.

A study found that stage II and III colorectal cancer patients who received conventional therapy along with 3 gm of PSK per day had a greater percentage of 5-year disease-free survival and a decreased relative risk of regional metastases. A meta-analysis of three trials involving 1,094 subjects with colorectal cancer confirmed that those who took PSK showed a significant improvement in overall survival and disease-free survival. In a meta-analysis of 8,009 gastric cancer patients from eight randomized controlled trials (RCTs), those taking PSK had increased survival.

A review of PSK used in human trials demonstrated improved immune function, tumor-related symptoms, and survival in patients with lung cancer when used as an adjunctive therapy. It improves survival in patients with Stage I, II, or III lung cancer and reduces bone marrow suppression.

Grifola Frondosa (maitake)

Grifola frondosa is an edible mushroom extensively used in traditional Asian medicine for numerous health-promoting purposes. Maitake means dancing mushroom. The maitake D-fraction is the bioactive extract that has been widely studied as an adjuvant therapy. It acts as a biologic response modifier, providing T-cell dependent immune enhancement and activation that enhanced antitumor effect. Maitake is often used to reduce the side effects of chemotherapy and make it more effective. It is most effective against breast, prostate, and liver cancer.

When maitake D-fraction was given to patients receiving chemotherapy for several different cancers, response rates increased from 12% to 28%, and chemotherapy side effects were reduced. Another study, among numerous others, suggests a direct antitumor effect of maitake D-fraction with induction of apoptosis observed in breast cancer cell lines.

Ganoderma Lucidum (reishi)

Reishi is often referred to as the mushroom of immortality. The mushroom itself is not edible due to its strong bitterness, but Ganoderma lucidum products are commercially available in many forms. Polysaccharides GL-PS and GL-T have the strongest anticancer activity. They can inhibit the cell cycle, are cytotoxic, and have antimetastatic, immunomodulatory, antioxidant, antimicrobial, and anti-inflammatory effects. GL-T is synergistic with doxorubicin in vitro and extracts reduce cardiotoxicity in rats. When GL-PS is combined with bleomycin, it reduces drug-induced pulmonary fibrosis in rats. G. lucidum extracts given in conjunction with cisplatin reduce nausea and vomiting, decrease nephrotoxicity, and enhance chemosensitivity in rats.

A Cochrane review of five RCTs concluded that G. lucidum could be administered as an adjuvant to conventional treatment, given its potential to enhance tumor response and stimulate host immunity. Patients who had been given G. lucidum with chemotherapy and/or radiation were 1.27 times more likely to respond versus those given conventional treatment alone. G. lucidum treatment alone did not demonstrate the same regression rate as that seen in combined therapy. Four of the studies found that patients in the G. lucidum group had improved quality of life.

Lentinula Edodes (shiitake)

Shiitake is the second largest cultivated and the most popular edible mushroom in the world. The polysaccharide extract active hexose correlated compound (AHCC) of the Lentinula edodes mushroom has been tested in several human trials. Eleven advanced cancer patients who were given 3 gm per day of AHCC for 1 month in an uncontrolled trial showed a 2.5 times increase in natural killer cell activity, and over half had a tumor response. Statistically significant increases in lymphocyte percentage, albumin levels, general physical health status, and maintenance of activities of daily living were reported in advanced liver cancer patients who were given AHCC instead of placebo. A cohort of 269 hepatocellular cancer patients who received curative resection was assigned to receive either 3 gm of AHCC daily or control after surgery. The treated group had a significantly longer disease-free interval, and increased overall survival. Lentinan is another polysaccharide extract of L. edodes. Long-term use in China has found it improves of quality of life and increases the efficacy of chemotherapy and radiation.

Hericium Erinaceus (Lion's Mane)

Hericium erinaceus is commonly used for its neuroprotective effects. Water and ethanol extracts have shown growth inhibitory effects on gastric, liver, and colon cancer cells. Oral administration to mice shows tumor suppressing activity similar to 5-fluorouracil. It also has antimetastatic activity and has shown a 50% reduction in lung metastases of colorectal cancer in mouse models. H. erinaceus extracts demonstrate numerous anticancer activities that are immunostimulatory, antimetastatic, pro-apoptotic, antioxidant, gastrointestinal protective, and inhibitory of angiogenesis.

Summary

While more research is still needed, mycomedicinals are showing promise for many cancer-related indications. Mycomedicinals are best absorbed when taken on an empty stomach. The typical dose of mycomedicinals varies from 800 mg to 3,000 mg of the active polysaccharide per day. Mycomedicinals rarely cause side effects, but they should be used with caution in patients with leukemia and lymphoma, those who have recently had a bone marrow transplant, and people on immunosuppressants (due to mushrooms effects on immune modulation).

What is turkey tail?

Turkey tail is a type of mushroom that grows on dead logs worldwide. It's named turkey tail because its rings of brown and tan look like the tail feathers of a turkey. Its scientific name is Trametes versicolor or Coriolus versicolor. In traditional Chinese medicine, it is known as Yun Zhi. In Japan, it is known as kawaratake (roof tile fungus). There are many other types of Trametes mushrooms. It can be hard to tell the difference between turkey tail and other types of Trametes mushrooms without the use of special testing.

Turkey tail has been used in traditional Chinese medicine to treat lung diseases for many years. In Japan, turkey tail has been used to strengthen the immune system when given with standard cancer treatment.

What is PSK?

Polysaccharide K (PSK) is the best known active compound in turkey tail mushrooms. In Japan, PSK is an approved mushroom product used to treat cancer.

How is PSK given or taken?

PSK can be taken as a tea or in capsule form.

Have any laboratory or animal studies been done using PSK?

In laboratory studies, tumor cells are used to test a substance to find out if it is likely to have any anticancer effects. In animal studies, tests are done to see if a drug, procedure, or treatment is safe and effective in animals. Laboratory and animal studies are done before a substance is tested in people.

Laboratory and animal studies have tested the effects of PSK on the immune system, including immune cells called natural killer cells and T-cells.

Have any studies of PSK been done in people?

PSK has been studied in patients with gastric cancer, breast cancer, colorectal cancer, and lung cancer. It has been used as adjuvant therapy in thousands of cancer patients since the mid-1970s. PSK has been safely used in people for a long time in Japan and few side effects have been reported.

Gastric cancer

Studies show that the use of PSK as adjuvant therapy in patients with gastric (stomach) cancer may help repair immune cell damage caused by chemotherapy and strengthen the immune system.

Studies of PSK as adjuvant therapy for gastric cancer include the following:

• A randomized clinical trial in Japan done between 1978 and 1981 included 751 patients who had surgery for gastric cancer. After surgery, patients received chemotherapy with or without PSK. On average, the patients who received chemotherapy and PSK lived longer than those who received chemotherapy alone. The researchers believe it might be possible to predict which patients would benefit the most from PSK depending on the numbers of granulocytes and lymphocytes in the patient’s blood.
• In 1994, a study in Japan followed 262 patients who had successful surgery for gastric cancer and were given chemotherapy with or without PSK. Patients who received chemotherapy and PSK were less likely to have recurrent cancer and lived longer than those who did not. Treatment with PSK caused few side effects. The researchers thought the study showed that PSK and chemotherapy should be given to gastric cancer patients after surgery to remove the cancer.
• A review published in 2007 combined results from 8 randomized controlled trials in 8,009 patients who had surgery to remove gastric cancers. After surgery, patients in the trials were given chemotherapy with or without PSK. The results suggest that receiving chemotherapy and PSK helped patients live longer after surgery.

Breast cancer

To date, PSK studies in patients with breast cancer have focused on changes in the immune system (T-cell and B-cell levels in the blood) rather than on clinical results (patient survival, symptoms, side effects, and quality of life).

Colorectal cancer

Studies of PSK as adjuvant therapy for colorectal cancer include the following:

• PSK was studied in a randomized clinical trial for its effect on the immune system in patients with stage II or stage III rectal cancer. Patients received chemotherapy and radiation therapy, with or without PSK. This study found that PSK increased the number of cancer-killing immune cells and had anticancer effects in tissue that received radiation therapy.
• A review that combined results from 3 studies in 1,094 patients with colorectal cancer found that patients who received PSK were less likely to have recurrent cancer and lived longer than those who did not.

Lung cancer

Studies of PSK as adjuvant therapy for patients with lung cancer include the following:

• Five nonrandomized clinical trials reported that patients treated with PSK and radiation therapy with or without chemotherapy lived longer.
• Six randomized clinical trials in patients with lung cancer studied chemotherapy with or without PSK. The studies showed that patients who received PSK improved in one or more ways, including immune function, body weight, well-being, tumor-related symptoms, or longer survival.

Have any side effects or risks been reported from turkey tail or PSK?

There have been few side effects reported in studies of PSK in Japan.

Is turkey tail or PSK approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

The U.S. Food and Drug Administration (FDA) has not approved the use of turkey tail or its active compound PSK as a treatment for cancer or any other medical condition.

The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure that they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of mushroom supplements may not be the same.

What is reishi?

Reishi is a type of mushroom that grows on live trees. Scientists may call it either Ganoderma lucidum or Ganoderma sinense. In traditional Chinese medicine, this group of mushrooms is known as Ling Zhi. In Japan, they are known as Reishi. In China, G. lucidum is known as Chizhi and G. sinense is known as Zizhi.

There are many other types of Ganoderma mushrooms and it is hard to tell the medicinal mushrooms from the other types.

Reishi has been used as medicine for a very long time in East Asia. It was thought to prolong life, prevent aging, and increase energy. In China, it is being used to strengthen the immune system of cancer patients who receive chemotherapy or radiation therapy.

How is reishi given or taken?

Reishi is usually dried and taken as an extract in the form of a liquid, capsule, or powder.

Have any laboratory or animal studies been conducted using reishi?

In laboratory studies, tumor cells are used to test a new substance and find out if it is likely to have any anticancer effects. In animal studies, tests are done to see if a drug, procedure, or treatment is safe and effective in animals. Laboratory and animal studies are done before a substance is tested in people.

Laboratory and animal studies have tested the effects of the active ingredients in reishi mushrooms, triterpenoids and polysaccharides, on tumors, including lung cancer.

Have any studies of reishi mushrooms been done in people?

Studies using products made from reishi have been done in China and Japan.

Lung cancer

Studies suggest that the use of products made from reishi as adjuvant therapy may help strengthen the immune system in patients with lung cancer.

Studies in patients with lung cancer include the following:

• In an open-label trial done in China, 36 patients with advanced lung cancer were given an over-the-counter product made from reishi called Ganopoly. The patients were being treated with chemotherapy or radiation therapy, along with other complementary therapies. Some patients had marked changes in the immune responses being studied, such as lymphocyte count and natural killer cell activity, and some patients had no change in immune response.
• In China, a study was done with 12 lung cancer patients. Their blood was tested to see if taking a product made from reishi could help improve immune response. The study found that the polysaccharides in reishi mushrooms may help cancer-fighting immune cells, called lymphocytes, stay active.

Colorectal cancer

The following study looked at reishi for the prevention of colorectal cancer:

• In Japan, 225 patients with benign colorectal tumors were studied. For 12 months, 123 of the patients were given an extract of the mushroom G. lucidum mycelia (MAK), while 102 patients did not receive treatment with MAK. At 12 months, a follow-up colonoscopy was done on all the patients. The number and the size of the tumors decreased in the group that received MAK, but not in the group that did not receive MAK. The researchers suggest that MAK may help stop benign colorectal tumors from forming.

Is reishi approved by the U.S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

The U.S. Food and Drug Administration (FDA) has not approved the use of reishi as a treatment for cancer or any other medical condition.

The FDA does not approve dietary supplements as safe or effective. The company that makes the dietary supplements is responsible for making sure they are safe and that the claims on the label are true and do not mislead the consumer. The way that supplements are made is not regulated by the FDA, so all batches and brands of mushroom supplements may not be the same.