A recent study conducted by scientists at the Fred Hutchinson Cancer Research Center in Seattle has reportedly revealed that high concentrations of omega-3 fatty acids—derived from fatty fish and fish-oil supplements—are associated with a 71-percent increased risk of high-grade prostate cancer. Theodore Braskey, et al., “Plasma Phospholipid Fatty Acids and Prostate Cancer Risk in the SELECT Trial,” Journal of the National Cancer Institute, July10, 2013. The findings, which apparently confirm a 2011 study published by the same scientific team, also showed a 44-percent increase in the risk of low-grade prostate cancer and an overall 43-percent increase in risk for all prostate cancers. The current study examined 834 men from the Selenium and Vitamin E Cancer Prevention Trial (SELECT) and 1,393 randomly chosen others who did not have cancer.

“We’ve shown once again that use of nutritional supplements may be harmful,” said Alan Kristal, the study’s senior author and member of the Fred Hutchinson Public Health Sciences Division. Noting that it is unclear why high levels of omega-3 fatty acids would increase prostate cancer risk, the scientists suggest that one potentially harmful effect of omega-3 fatty acids is “their conversion into compounds that can cause damage to cells and DNA, and their role in immunosuppression.”

“What’s important is that we have been able to replicate our findings from 2011 and we have confirmed that marine omega-3 fatty acids play a role in prostate cancer occurrence,” said co-author Theodore Brasky. “It’s important to note, however, that these results do not address the question of whether omega-3’s play a detrimental role in prostate cancer prognosis.” According to Kristal, the findings in both studies were surprising “because omega-3 fatty acids are believed to have a host of positive health effects based on their antiinflammatory properties.” See Fred Hutchinson Cancer Research Center News Release, July 10, 2013.