Study finds no link between fish oil, lower cancer incidence

Contrary to popular thinking, consuming food or dietary supplements such as fish oil that contain omega-3 fatty acids provides no protection against developing cancer, according to a study examining 4 decades of medical literature (JAMA 2006; 295:403-15).

No significant associations between omega-3 fatty acid consumption and cancer were found for several cancers, including bladder cancer, according to the authors from RAND Health and the Greater Los Angeles VA Healthcare System. For prostate cancer, the researchers noted one estimate of decreased risk (RR, 0.43; 95% CI) and one estimate of increased risk (RR, 1.98; 95% CI) for advanced prostate cancer; 15 other estimates did not show a significant association.

“We identified a few studies that showed reduced risk of cancer from consuming omega-3 fatty acids. But we found even more studies that showed no decrease in cancer risk and even a few that suggested a higher risk,” said lead author Catherine MacLean, MD, PhD. “Our conclusion is that there is no relationship between omega-3 fatty acids and lower rates of any types of cancer.”

After reviewing more than 1,000 articles published between 1966 and 2005, the team found 38 reports that provided high-quality information about the possible link between consumption of fish oil and the incidence of 11 types of cancer.