Study Finds No CVD Benefit With Omega-3 Fatty Acids

March 17, 2014

WASHINGTON, DC — Supplementing the diets of elderly patients with a moderate dose of long-chain omega-3 fatty acids failed to reduce CVD risk, a new study shows. Taking omega-3 fatty-acid supplements for nearly five years failed to reduce the incidence of CVD mortality, MI, stroke, unstable angina, revascularization, CHF hospitalizations, and resuscitated cardiac arrest, report investigators[1].

"The results of the study show that there is no safety signal, so there's no harm at the levels that were given, but it doesn't demonstrate any benefit in taking dietary supplements in terms of CV outcomes," lead investigator Dr Denise Bonds (National Institutes of Health, Bethesda, MD) told heartwire .

Published March 17, 2014 in JAMA Internal Medicine, the trial is an ancillary study of the Age-Related Eye Disease Study 2 (AREDS2), which includes 4203 men and women treated at US ophthalmology clinics. As part of the factorial-design randomized trial, individuals were treated with 350-mg docosahexaenoic acid  and 650-mg eicosapentaenoic acid (EPA) for 4.8 years. Approximately 20% of randomized participants had a history of CVD. Participants were also treated with the macular xanthophylls lutein and zeaxanthin to determine impact on CV outcomes.

Regarding the primary end point, a composite of CV mortality and morbidity, supplementation with omega-3 fatty acids failed to provide any reduction in clinical events. In terms of secondary end points, which included multiple combinations of components of the primary end point, there was also no reduction in events. In an exploratory analysis, the researchers did not observe any significant difference in clinical-event rates among those with high or normal triglycerides.

Supplementation with lutein and zeaxanthin also failed to reduce CV morbidity and mortality.

In an editorial[2], Drs Evangelos Rizos (University Hospital of Ioannina, Greece) and Evangelia Ntzani (University of Ioannina School of Medicine, Greece) point out that sales of omega-3 fatty acids were over $25 billion in 2011 and continue to grow. The US Food and Drug Administration (FDA) has approved omega-3 fatty acids for hypertriglyceridemia, and the European Medicines Agency has approved them as adjuvant treatment in post-MI patients. However, their use for CV-risk modification remains controversial.

The editorialists point out that the present study was likely underpowered to detect a significant benefit in CV outcomes because the researchers assumed a 25% reduction in the primary end point. The current study, they add, is just one of countless others that continue to test the link between supplementation with omega-3 fatty acids and CV risk. Given these and other results, patients should be informed of the uncertainty surrounding the effect of omega-3 fatty acids on heart health and instead encouraged to regularly consume whole fish.

"What is evident so far is that omega-3 supplementation with daily doses close to 1 g in patients with or without established CVD shows no clear, considerable benefit," write Rizos and Ntzani. "Continuing to conduct more randomized, controlled trials seems unjustified." The field, they add, would be better served by conducting a large meta-analysis or focusing on higher-risk populations, such as those with triglycerides greater than 200 mg/dL.

To heartwire , Bonds said her recommendations for patients would be to focus on consuming a heart-healthy diet that includes fish, which the editorialists agree with, given the epidemiologic evidence supporting whole-fish consumption.

Last October, an FDA advisory panel voted against approval of an expanded indication for a highly purified ethyl ester of EPA for use in combination with a statin in patients with mixed dyslipidemia and CHD or a CHD risk equivalent. Despite reducing lipid parameters, the panel was concerned about the lack of benefit on hard CV outcomes.

Full disclosures for the authors and editorialists are listed in the article and editorial.

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