We always like to hear stories relating to food ingredients that have the potential to prevent or treat cancer. A new study published in the March edition of the Journal of pharmacology and experimental therapeutics does just this by adding further support for the role of long-chain omega-3s in cancer prevention and, in this case, specifically for EPA. The refreshing nature of this study is in stark contrast to the scare-mongering and alarming report that faced us in 2013 (the omega-3 and prostate cancer scare!) With a plethora of supportive studies indicating the anti-cancer benefits attributed to omega-3, it only takes one badly designed study to throw the cat amongst the pigeons. The ‘fishy’ nature of Brasky and colleagues 2013 study  was quickly exposed by leading scientists, not only for its poor design, but also for the speed at which unfounded conclusions were jumped to.
What does this new study tell us?
One of the key targets for cancer prevention (or treatment) is via the inhibition of the tumour growth by stopping the division of cancer (or pre-cancer) cells. Omega-3s are well documented for their anti-inflammatory and anti-proliferative properties and in this study EPA exhibited its anti-cancer properties by binding to FFA4 (free fatty acid receptor 4), suppressing proliferation by triggering signals that inhibit cancer cell growth.  Interestingly, and in keeping with other studies of this nature, this was a characteristic attributed to EPA rather than DHA. Whilst this study was performed in vitro, and caution should be observed with regard to relating these findings to human intervention, it does provide valuable mechanistic information relating to the anti-inflammatory role of EPA. Indeed, the action of EPA as an anti-inflammatory cyclooxygenase (COX)-2 inhibitor has been demonstrated as a potentially effective chemopreventive tool against colorectal cancer in both animals  and humans  and encouragingly is now at phase III trial stage. The primary aim of the ongoing trial is to determine if 2g EPA daily (as rTG) prevents the development of colorectal adenomas, either alone or in combination with aspirin.  If EPA is shown to be an effective way to reduce bowel polyps, it may also reduce future bowel cancer risk, thus opening up the same potential as an intervention tool for prostate cancer prevention.
- Brasky TM, Darke AK, Song X, Tangen CM, Goodman PJ, Thompson IM, Meyskens FL, Jr., Goodman GE, Minasian LM, Parnes HL, et al: Plasma phospholipid fatty acids and prostate cancer risk in the SELECT trial. Journal of the National Cancer Institute 2013, 105:1132-1141.
- Liu Z, Hopkins MM, Zhang Z, Quisenberry CB, Fix LC, Galvan BM, Meier KE: Omega-3 fatty acids and other FFA4 agonists inhibit growth factor signaling in human prostate cancer cells. The Journal of pharmacology and experimental therapeutics 2015, 352:380-394.
- Fini L, Piazzi G, Ceccarelli C, Daoud Y, Belluzzi A, Munarini A, Graziani G, Fogliano V, Selgrad M, Garcia M, et al: Highly purified eicosapentaenoic acid as free fatty acids strongly suppresses polyps in Apc(Min/+) mice. Clin Cancer Res 2010, 16:5703-5711.
- Higurashi T, Hosono K, Endo H, Takahashi H, Iida H, Uchiyama T, Ezuka A, Uchiyama S, Yamada E, Ohkubo H, et al: Eicosapentaenoic acid (EPA) efficacy for colorectal aberrant crypt foci (ACF): a double-blind randomized controlled trial. BMC Cancer 2012, 12:413.
- Hull MA, Sandell AC, Montgomery AA, Logan RF, Clifford GM, Rees CJ, Loadman PM, Whitham D: A randomized controlled trial of eicosapentaenoic acid and/or aspirin for colorectal adenoma prevention during colonoscopic surveillance in the NHS Bowel Cancer Screening Programme (The seAFOod Polyp Prevention Trial): study protocol for a randomized controlled trial. Trials 2013, 14:237.