A systematic review published in this week's JAMA shows that fish oil does not prevent cancer. The review analyzed the results of 38 prior studies of the effect of fish oil on the risk of cancers of the breast, colon, lung, prostate, skin, and other sites. Individual study results varied. Some showed increased risk from fish oil, others showed reduced risk, and most showed no effect. The combined result was that fish oil has no evident protective effect against cancer.
- MacLean CH, Newberry SJ, Mojica WA, et al. Effects of omega-3 fatty acids on cancer risk: a systematic review. JAMA 2005;295:403-415.