Hot topics                    

Wednesday 2 July 2008

RAPID ROUNDUP: Broccoli and prostate cancer (PLoS ONE) – experts react.

A new report published in the online, open-access journal PLoS ONE on July 2, looks into how eating broccoli could alter men’s chances of developing prostate cancer. In the study men who were at risk of developing prostate cancer ate either 400g of broccoli or 400g of peas per week in addition to their normal diet over 12 months. Tissue samples were taken from their prostate gland before the start of the trial and after 6 and 12 months, and the expression of every gene measured. It was found that there were more changes in gene expression in men who were on the broccoli-rich diet than on the pea diet, and these changes may be associated with the reduction in the risk of developing cancer, that has been reported in epidemiological studies.

The full paper is available here

The AusSMC has rounded up Australian experts to comment on this research. Feel free to use the comments below in your stories. If you would like to speak to an expert please don’t hesitate to contact us on (08) 8207 7415 or by email.

Professor Ian Olver, is CEO of The Cancer Council Australia

“Previous studies have shown a link between eating broccoli and a decreased risk of prostate cancer. However, it isn’t clear that one causes the other. In this new study, a mechanism has been discovered where a change in the genetic structure occurs, which could explain what has been found. The study is, however, only small, and further work will have to be done to prove the association between broccoli and reduced prostate cancer.”

An audio file of Prof Ian Olvers comments is available here

Dr Michael Fenech, is Principal Research Scientist CSIRO Human Nutrition

““The studies of Professor Richard Mithen and colleagues suggest that eating broccoli instead of peas over a 12 month period alters gene expression in the prostate of individuals with a common mutation in the GSTM1 gene. The changes in gene expression due to broccoli consumption did not cause a reduction in plasma levels of PSA which is a biomarker of prostate cancer risk and no evidence is provided to indicate changes in the carcinogenic process such as reduction in genome instability or cell proliferation occurred in the prostate tissue. Although increased intake of broccoli and cruciferous vegetables has been associated with reduced prostate cancer risk in some epidemiological studies there is little direct evidence to suggest that eating more broccoli protects you against prostate cancer if you are susceptible due to any genetic or environmental factor. The results of the gene expression study indicate that different foods affect gene expression depending on one’s genotype however this does not mean a direct association with prostate cancer causality. In other words the study does not prove that eating broccoli is better than eating peas for prevention of prostate cancer”.