Science knowledge is brought to the public’s doorstep via journalists and the messages are open to misrepresentation of the facts. The alarmist news headlines that greeted us on the morning of 11th July would have us believe that we should avoid omega-3 fish oil supplements at all costs. Not all omega-3 are the same, however, and the take-home message from this study should really be along the lines of “don’t tar EPA and DHA with the same brush”.
Why are we being advised as such? Because a new study published in the Journal of the National Cancer Institute has reported an increased prostate cancer risk among men with high blood concentrations of long-chain omega-3 fatty acids.  The case-control study in question looked at associations between plasma phospholipid fatty acids and prostate cancer risk, with fatty acids categorised into quartiles based on their distribution amongst the participants. Compared with men in the lowest quartile of total omega-3, men in the highest quartile had a 44% increased risk for low-grade prostate cancer and a 71% increased risk for high-grade prostate cancer. It is this data only that has been distributed by the media and it certainly suggests that all omega-3 contribute to an increased risk.
When, however we look at the individual fatty acids – EPA and DHA – as the researchers measured in this study, rather than omega-3 as a whole, the picture is very different. Indeed it appears that DHA and not EPA is responsible for the statistically significant increased risk. As individual fatty acids, EPA and DHA tell very different stories, one that is essentially masked by the detrimental effects of DHA when the two are expressed as total data together. Interestingly, the findings of this study are extremely similar to a previously published article by the same authors in 2011. Reporting their findings from the Prostate Cancer Prevention Trial, the group published data showing DHA to be significantly and positively associated with the risk of high-grade prostate cancer whilst EPA was not. Again, when combined as EPA and DHA (total omega-3) the association was similar to that of DHA.
Research on the function of EPA and DHA, both together and as individual fatty acids, has progressed significantly in the last couple of decades. Indeed, simply ‘throwing them into the same pot’ and labeling them as ‘omega-3’ is no longer viable. Because DHA is the most unstable of the long-chain omega-3s, the products of lipid peroxidation derived from DHA supplementation may actually counteract the benefits normally attributed to omega-3. As such, the Igennus range of pure EPA oils offer the safest and most convenient way to increase omega-3 intake.
- Brasky et al., Plasma Phospholipid Fatty Acids and Prostate Cancer Risk in the SELECT Trial. J Natl Cancer Inst (2013)
- Brasky et al., Serum Phospholipid Fatty Acids and Prostate Cancer Risk: Results From the Prostate Cancer Prevention Trial Am J Epidemiol. 2011 173:1429-39.