Too Much Fish Oil Might Boost Prostate Cancer Risk
Often-fatal aggressive disease of particular concern
The study would have to account for other risk factors for prostate cancer before it could be considered definitive, he said. These include family history, age and race, among others, D'Amico explained.
For the study, researchers used data from the Selenium and Vitamin E Cancer Prevention Trial, which found no benefit from either of these nutrients but an increase for prostate cancer for vitamin E.
The researchers compared blood levels of omega-3 fatty acids in more than 800 men later diagnosed with prostate cancer with blood samples from nearly 1,400 men who did not develop the disease.
The difference in blood levels of omega-3 fatty acids between the lowest- and highest-risk groups was about 2.5 percent (3.2 percent versus 5.7 percent) -- a gap larger than achieved by eating salmon twice a week, the researchers noted.
The investigators found that men eating the most fatty fish and taking the most fish oil supplements had an overall 43 percent increase in risk for all prostate cancer, compared with men eating the least fish or taking the fewest supplements. The risk for aggressive prostate cancer was 71 percent higher; for non-aggressive prostate cancer, the risk was 44 percent greater.