Higher levels of eicosapentaenoic acid, a type of omega-3 polyunsaturated fatty acid, were associated with a significantly reduced risk of heart failure in a large, multi-ethnic cohort of adults in the United States.
Despite the potential benefits of omega-3s eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for heart health, their use has been controversial, although data in a mouse model showed that dietary EPA was protective against heart failure, wrote Robert C. Block, MD, of the University of Rochester (N.Y.), and colleagues. Their report is in the Journal of the American College of Cardiology.
To examine the impact of EPA on heart failure in humans, the researchers used data from the Multi-Ethnic Study of Atherosclerosis (MESA), a longitudinal cohort study of U.S. adults, including those who are African American, Hispanic, Asian, and white.
The researchers included 6,562 MESA participants aged 45-84 years from six communities. Participants underwent a baseline exam between July 2000 and July 2002 that included phospholipid measurements used to identify plasma EPA percentage, and they completed study visits approximately every other year for a median follow-up of 13 years.
A total of 292 heart failure events occurred during the follow-up period: 128 with reduced ejection fraction (EF less than 45%), 110 with preserved ejection fraction (EF at least 45%), and 54 with unknown EF status.
The percent EPA for individuals without heart failure was significantly higher compared with those with heart failure (0.76% vs. 0.69%, P =.005). The association remained significant after the researchers controlled for age, sex, race, body mass index, smoking, diabetes, blood pressure, lipids and lipid-lowering drugs, albuminuria, and the lead fatty acid (defined as the fatty acid with the largest in-cluster correlation).
An EPA level greater than 2.5% was considered sufficient to prevent heart failure based on prior definitions. A total of 73% of the participants had insufficient EPA (less than 1.0%), 2.4% had marginal levels (1.0%-2.5%), and 4.5% had sufficient levels. However, given that EPA levels can be easily and safely increased with the consumption of seafood or fish oil capsules, increasing EPA is a feasible heart failure prevention strategy, the researchers said.
The study included 2,532 white, 1,794 black, 1,442 Hispanic, and 794 Chinese participants. Overall, the fewest Hispanic participants met the criteria for sufficient EPA (1.4%), followed by black (4.4%), white (4.9%), and Chinese participants (9.8%).
The study findings were limited by several factors, including relatively few participants with preserved ejection fractions and sufficient EPA levels, as well as the inability to account for changes in omega-3 levels and other risk factors over time, the researchers noted.
“We consider this study to strongly determine a benefit of EPA exists, but insufficient to determine whether a threshold for %EPA exists near 3%,” they said. They proposed a follow-up study including individuals with higher levels of EPA to better detect a protective effect.
Lead author Dr. Block had no financial conflicts to disclose. Several coauthors received honoraria from Amarin Pharmaceuticals. The study was funded in part by the National Heart, Lung, and Blood Institute.