More research needed into effect of oily fish on prostate risk

In collaboration with the Press Association

Cancer Research UK has said that more research is needed to investigate the effect of eating oily fish on men's risk of prostate cancer after US scientists claimed that it may provide protection against aggressive forms of the disease.

A research report in the journal Clinical Cancer Research suggests that omega-3 fatty acids may protect against advanced prostate cancer, even in men with a faulty gene that places them at higher risk.

Scientists at the University of California-San Francisco recruited 466 men with aggressive prostate cancer and a further 476 cancer-free men.

Participants provided information on their intake of oily fish and were tested for variations of the COX-2 gene, which is involved in inflammation . Certain variants of this gene are linked to an increased risk of prostate cancer.

The scientists found that men who reported that they ate the most omega-3 were less likely to have prostate cancer than men who ate the least.

Men who had the 'high risk' variant of COX-2, and who ate a low omega-3 diet, were five times more likely to have prostate cancer.

However, men who had the high risk gene, but who ate a high-omega-3 diet, had a normal risk.

The researchers believe that this is preliminary evidence that omega-3 fatty acids could prevent prostate cancer, although more work is needed to confirm this.

Dr John Witte, professor of epidemiology and biostatistics at the University of California-San Francisco, commented: "Previous research has shown protection against prostate cancer, but this is one of the first studies to show protection against advanced prostate cancer and interaction with COX-2."

However, Cancer Research UK urged caution over the findings, pointing out that the study only looked at a single point in time, rather than following men over a number of years.

Science information manager Dr Joanna Owens said: "We already know that combining certain elements of the Mediterranean diet can reduce cancer risk - and this includes eating plenty of fish.

"But the links between diet and cancer risk are complex and we need much larger studies to know for sure whether eating more oily fish could specifically reduce the risk of prostate cancer."