Mushrooms are often talked about as a treatment for cancer. There is currently no evidence that any type of mushroom can prevent or cure cancer.
- There are many different species of mushroom.
- Chinese medicine practitioners use mushrooms as a treatment for illness.
- There is no evidence that mushrooms or mushroom extract can prevent or cure cancer.
What are medicinal mushrooms?
In traditional chinese medicine mushrooms are used to treat illness. They are also known as medicinal mushrooms.
Mushrooms are part of the fungus family and there are hundreds of different species. They have been a part of traditional chinese medicine for centuries.
Why people with cancer use it
Button mushrooms and flat mushrooms are commonly eaten in the UK. They contain all the essential amino acids and are a good source of vitamins. So they can be used as part of a healthy diet. But there is no evidence that they can treat cancer.
In the UK, powdered shiitake, maitaki and reishi (also called ganoderma) mushrooms are available. You can also sometimes get preparations of their juices. These are sold in health food shops. As far as we know, there is nothing in the mushrooms or compounds that would be harmful but we don't currently know how helpful they are in cancer care.
Mushrooms in Chinese medicine
Practitioners of Chinese medicine use more than 100 species of mushroom as treatments for a wide range of illnesses. There are different ways of taking these mushrooms. You eat them fresh or dried or take extracts as food supplements.
Mushrooms alongside cancer treatments
In China, Japan and Korea they sometimes use purified mushroom compounds alongside chemotherapy and radiotherapy.
In 2000, a report published by Cancer Research UK and the University of Strathclyde looked at different types of mushroom and cancer. The review found some Japanese studies that used a particular type of exotic mushroom extract a week before people started cancer treatment. The extract appeared to reduce the side effects of both chemotherapy and radiotherapy, including sickness and hair loss.
Mushrooms and the immune system
Some studies seemed to show that these mushrooms could stimulate the immune system to fight disease. There is some evidence from a Japanese study that people who eat a particular type of mushroom all their lives have a lower risk of getting cancer. The mushrooms did seem to affect the cancer in some people. But we have to be very cautious about the results because most of these early trials were not randomised or controlled. So, there was no proper comparison made between patients having the mushrooms and similar patients not being treated with mushrooms or drugs developed from mushrooms. So the studies can't really show whether the mushrooms helped or not.
Some more recent research has looked at some particular mushrooms and their extracts. This includes:
Shiitake mushrooms are native to East Asia but are grown worldwide for their supposed health benefits. They are valued in some cultures as an anti cancer agent.
The fresh and dried forms of the mushroom are commonly used in East Asian cooking. Extracts from the mushroom, and sometimes the whole dried mushroom, are used in herbal remedies.
One shiitake extract called lentinan is a beta glucan. This is a type of complex sugar compound. Beta glucan is believed to stimulate the immune system and trigger certain cells and proteins in the body to attack cancer cells. In laboratory studies, it seems to slow the growth of some cancer cells.
In mice, lentinan has been shown to stop bowel cancer cells growing. In laboratory tests, the protein part of lentinan (lentin) can stop some fungal cells growing. It can also stop leukaemia cells dividing.
Some Japanese researchers give lentinan along with chemotherapy to treat patients with lung, nose, throat, and stomach cancers.
A recent clinical trial didn't show that it helped to treat prostate cancer. Some doctors in Japan use another shiitake extract called eritadenine.
There is limited evidence that lentinan, given alongside chemotherapy, could help some patients with advanced stomach cancer.
We need larger scale studies before we will know how shiitake extracts can help people with cancer.
More clinical trials are currently under way to understand which compounds in shiitake mushrooms might work as cancer treatments.
Maitake mushrooms and the maitake D-fraction prepared from them contain the sugar compound called beta glucan (sometimes called beta glycan).
Japanese studies using an injectable type of maitake-D have found that it boosted the immune system and slowed or stopped the spread of breast and liver cancer in animal studies.
A phase 1 study in the USA is looking to see whether beta glucan can help a biological therapy called rituximab to work better. It is for young patients with lymphoma or leukemia that has come back after previous treatment.
Another trial is looking at whether maitake extract affects breast cancer.
A US study tested another complex sugar compound from maitake mushrooms called grifola frondosa in breast cancer patients.
The study aimed to find out if the extract affected the immune system. Patients took the extract by mouth for 3 weeks. The researchers took blood tests to measure any effects.
One patient stopped taking the extract because of sickness and joint swelling. Another stopped because of a rash and itching.
The researchers found that the extract boosted some immune functions but slowed others. We don't yet know whether this compound can help the immune system to fight cancer.
A Brazilian study gave patients agaricus sylvaticus mushrooms as part of their diet after bowel cancer surgery.
It found that patients who had the mushrooms had a better quality of life compared to patients who didn't have the mushrooms.
The benefits included:
- more ability to do physical exercise
- less feeling sick
- better mood
- fewer aches and pains
- better sleep
- better appetite
- less abdominal pain, especially after eating
- fewer bowel problems such as constipation, diarrhoea, and wind
Used for centuries in Eastern Ancient medicine, this extract is believed to refresh bodies and extend life.
Phellinus linteus is known as song gen in Chinese medicine, sang-hwang in Korean and meshimakobu in Japanese.
Recent studies have shown that this type of mushroom extract slows the growth of breast cancer cells in the laboratory. It has also been shown to have anti cancer effects on skin, lung and prostate cancer cells.
One study showed that when used in combination with the chemotherapy drug doxorubicin, the extract increased the number of prostate cancer cells killed.
We have to be cautious about such early research. Substances that can kill cells in laboratory conditions don't necessarily turn out to be useful treatments in people.
Safety of mushroom and mushroom extracts
There are no known side effects from eating normal amounts of mushrooms in our diet. Mushroom extracts are classed as dietary supplements.
Most of these supplements have not been tested to find out if they interact with medicines, foods, or other herbs and supplements.
Shiitake mushroom extracts are generally considered safe, although there are some reports of diarrhoea or bloating.
With other types of mushroom there are some reports of allergic reactions affecting the skin, nose, throat, or lungs.