Increased intake of fish oil omega-3 fatty acidsmay protect against advanced prostate cancer

April 02, 2009

According to new research from the University of California San Francisco the Omega-3 fatty acids from fish oils (EPA and DHA) decrease the risk of developing advanced-dangerous prostate cancer and they may achieve this by modifying a specific variant of the COX-2 gene, a known inflammatory gene. The gene variant (known as rs4647310) is very dangerous and is linked to a five-fold increased risk of developing advanced prostate cancer, report the researchers, but high intakes of omega-3 may have a reduced risk, even if they carried the COX-2 variant. “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,” said lead researcher Professor John Witte.

The study adds to a growing body of evidence linking fish consumption and omega-3 to potential cancer benefits. Indeed, previous results in the journal Cancer Epidemiology, Biomarkers & Prevention reported that higher intake of the omega-3 fatty acids DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) cut the risk of developing prostate cancer by 40%.

Dr. Witte et al performed a case-control analysis of 466 men with aggressive prostate cancer and 478 healthy men. The researchers used food frequency questionnaires to assess the diet of the individuals, and they also genotyped nine COX-2 single nucleotide polymorphisms. The highest average intakes of omega-3 fatty acids were associated with a 63% reduction in the risk of aggressive prostate cancer, compared to men with the lowest amount of long chain omega-3 fatty acids, said the researchers. “Our findings support the hypothesis that long chain omega-3 fatty acids may impact prostate inflammation and carcinogenesis through the COX-2 enzymatic pathway,” wrote the researchers. When the analysis was focused on the rs4647310 variant, they found that, despite an increase in the risk of prostate cancer in men with this variant, high intakes of omega-3 substantially reduced the risk. “The COX-2 increased risk of disease was essentially reversed by increasing omega-3 fatty acid intake by a half a gram per day,” said Witte. “If you want to think of the overall inverse association in terms of fish, where omega-3 fatty acids are commonly derived, the strongest effect was seen from eating dark fish such as salmon one or more times per week.” The study is published on line ahead of print in the journal Clinical Cancer Research.