Summary

• Mushrooms contain compounds that have been linked to lowering the risk of a range of cancers.
• Compounds such as lectins and other unique proteins, glucans and other special carbohydrates, all have the potential to inhibit cancer formation and growth.
• Three population studies show that women who eat an average of one button mushroom a day have half the risk of breast cancer than women who do not eat mushrooms.
• A meta-analysis of the link between mushroom eating and breast cancer confirms that there is a definite link, with mushroom consumption reducing the risk of the cancer.
• There is ongoing research to determine if fresh mushrooms and mushroom extracts can help to lower the risk of cancer, especially breast and prostate cancer.

Mushrooms help fight cancer

Like many people, you probably eat for both enjoyment and to protect your health against future disease. Fruits and vegetables help reduce the risk of heart disease, stroke and some cancers. It is not surprising that mushrooms have also been found to play their part in lowering cancer risk, even though they are neither fruit nor vegetable. 

Research shows that mushroom extracts reduced breast cancer growth (Chen 2006; Martin 2010). “Eating 100 grams, or even less, of mushrooms per day could have an effect on preventing new breast cancers,” said lead researcher Dr Shiuan Chen. Soon after the early finding there were three international studies linking women who eat mushrooms to a 50-60% lower risk of breast cancer compared to those who do not eat mushrooms (Shin 2010; Hong 2008).

One study from the University of Western Australia showed that women who ate an average of only 10g of mushrooms (about half a button mushroom) a day had a 65% lower risk of breast cancer (Zhang 2009). That has been quite a remarkable finding, stimulating more research on how mushrooms might reduce cancer risk. As the CSIRO said: The most promising data appear to be those indicating an inverse relationship between mushroom consumption and breast cancer risk. 

2014 CSIRO Mushrooms and Health Report 

There have now been ten good quality observational studies revealing that women who eat mushrooms regularly have a much lower risk of breast cancer. A 2014 meta-analysis states: “The protective effects of mushroom intake on risk of breast cancer were consistently exhibited in premenopausal and postmenopausal women.” (Li 2014)

How do mushrooms help to protect against breast cancer?

The mushroom contains compounds that suppress two enzymes called aromatase. Aromatase converts the hormone androgen to estrogen, which in turn can promote the development of breast cancer, especially in post-menopausal women (Grube 2001; Chen 2006). Currently, aromatase inhibitors are being used in the treatment of estrogen-dependent breast cancer. An Australian study showed that two carbohydrates found in mushrooms inhibited breast cancer cell growth in the laboratory (Jeong 2012).

Potential to reduce prostate cancer risk

The enzyme 5 alpha reductase converts the hormone testosterone to dihydrotestosterone and is thought to play a role in the development of prostate cancer and benign prostate enlargement in men. The research on animal cells suggests that compounds in mushrooms inhibit this enzyme, therefore having a potential role in the protection against prostate cancer (Adams 2008). 

An unpublished study from the Beckman Research Institute, USA, has found that consuming 1-4 button mushrooms daily does significantly drop Prostate Specific Antigen levels (PSA test) in one-third of men with high PSA levels. Interviews with two men who reversed their high PSAs with mushrooms can be found here.

Although it is too early to say that eating mushrooms will stop you from getting breast or prostate cancer, the future looks very promising for the role mushroom could have in reducing the risk of these two common cancers. On-going research is checking to see if mushrooms play a very specific role in protecting against cancer. You can see researcher Dr Chen’s thoughts here. He appears at 1.40. 

It is unlikely that any one nutrient or compound in food provides the protection against cancer. It is far more likely that the synergy of the many compounds in mushrooms, and food in general combine effectively to offer protection to the body. That means eating a healthy diet, one that includes mushrooms, which are a very useful source of B vitamins, minerals and antioxidant compounds.