Recently, a study was widely publicized in the mass media showing an increased risk of prostate cancer for men with higher versus lower omega-3 blood levels. Check this out for Dr. O’Keefe’s statement regarding these reports:
This was a retrospective case-control study that showed miniscule differences in omega-3 blood levels: 3.62% in the no-cancer control group, 3.66% in the prostate cancer group). For example, a headline in the Huffington Post yesterday read: “Omega-3 supplement taken by millions linked to aggressive prostate cancer.” This is blatantly untrue. To have an omega-3 blood level of 3.6 to 3.7% range is compatible with little to no fish consumption, and no fish oil capsule intake in BOTH arms of the study.
Japanese men consume about 8 times more fish than American men, and on average have an omega-3 index of 8 to 10% (over twice as high as either group in this study). Japanese men have a prostate cancer level that is less than one-sixth that noted in American men. Prior studies from other investigators have suggested if anything lower rates of prostate cancer with higher intake of fish and omega-3 fatty acids.
Higher omega-3 levels have been consistently and strongly correlated with lower risks for cardiovascular mortality, sudden cardiac death, all-cause mortality and genetic aging at a cellular level (slowing telomere attrition).
Bottom Line: In my opinion, this study is largely irrelevant clinically. I recommend to continue to emulate the Japanese and keep omega-3 levels at or above 8%.