WHAT’S NEW: More evidence of little benefit
The meta-analysis by Rizos et al is the most up-to-date, comprehensive look at the value of omega-3 fatty acids for primary and secondary prevention of cardiovascular events.It differs from previous reviews in that most included studies were well-done RCTs. In addition, the studies were performed in both primary and secondary cardiovascular disease prevention settings and involved different forms of omega-3 PUFA supplementation, including dietary sources and supplements. The trials were predominantly larger than those included in previous systematic reviews, as well. The baseline risk for cardiovascular disease in the newer studies (7 of the 20 RCTs were completed after 2007) may be different from that of previous studies because of increased use of certain medications,such as statins. In recent years, other studies of omega-3 PUFAs have had similar results. A metaanalysis of 14 RCTs found that omega-3 PUFA supplementation offered no benefit for the secondary prevention of cardiovascular disease.8 The FORWARD trial—published earlier this year—showed that omega-3 PUFAs did not decrease the recurrence of atrial fibrillationin patients with a history of confirmed paroxysmal atrial fibrillation.9 And an earlier(2006) analysis of RCTs and cohort studies found no benefit from omega-3 fatty acids for primary prevention of cardiovascular disease or cancer.10
CAVEATS: No significant help, and no harm
There’s no need to tell patients who wish to take omega-3 supplements not to do so, but we should not promote their use for the sole purpose of cardiovascular disease protection.
While this meta-analysis found no statistically significant benefits from omega-3 PUFAs, there is no evidence of harm from PUFA intake, whether from dietary sources or supplements. There is no need to tell patients who wish to take omega-3 supplements not to do so. But we should not promote their use for the sole purpose of cardiovascular disease prevention.
CHALLENGES TO IMPLEMENTATION: Changing minds won’t be easy
Despite recent findings indicating that omega-3 PUFAs provide little primary or secondary protection against cardiovascular events, advertising from supplement manufacturers may make it hard to change patients’ minds. Because diets and supplements containing these fatty acids do not cause apparent harm, patients and physicians may decide that a small potential benefit is worth the expense.
Acknowledgement
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center for Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.
