Research published in the April 25 online edition of the American Journal of Epidemiology concluded that men with the highest blood levels of an inflammation-lowering omega 3 fatty acid (docosahexaenoic acid or DHA) (most often found in fatty fish) have a 2 1/2 times greater probability of developing aggressive, high grade prostate cancer than men who had the lowest DHA levels. On the other hand, men with the highest blood ratio of trans-fatty acids had a 50 percent reduction in the probability of high grade prostate cancer. Trans-fatty acids are found in processed foods and are linked to inflammation and heart diseases. In addition, neither of the fats increased the risk of low-grade prostate cancer. Researchers expected the opposite results, that is, omega-3 fatty acids would reduce prostate cancer risk and omega-6 and trans-fatty acids would increase prostate cancer risk.
Data for this study was provided by a subset (over 3,400 men) of a larger sample in the nationwide Prostate Cancer Prevention Trial with men age 55 and older. Half of the men developed prostate cancer during the study and half did not and prostate cancer was confirmed by prostate biopsy. Few in the sample took fish oil supplements-the most common non-food source of omega 3 fatty acids-but got their omega 3 from fish. The authors concluded “the beneficial effects of eating fish to prevent heart disease outweighs any harm related to prostate cancer risk.” “What the study shows is the complexity of nutrition and its impact on disease risk, and that we should study suxch assocoatopns rigorously rather than make assumptions.”
