Having a greater Omega-3 index (the concentration of omega-3 fatty acids in the blood) is associated with a significantly reduced risk of heart failure and cardiovascular mortality, according to a new study published in Mayo Clinic Proceedings.

The study relied on data from 272,000 adults who participated in the UK Biobank. Researchers used Cox proportional hazards models to predict incident heart failure in those without baseline heart failure, and total/cardiovascular mortality in those with baseline heart failure, all as a function of baseline plasma omega-3 levels.

They found that people who were in the top 20% highest omega-3 fatty acid levels were 21% less likely to develop heart failure over a 13.7-year follow-up period, compared to the bottom 20%.

In the 1,239 people with a diagnosis of heart failure at enrollment, those in the top 20% of plasma omega-3s were 50% less likely to die from any cause during follow-up compared with those in the bottom 20%.

The authors noted that because the study was observational, causality cannot be determined through these findings alone. However, they pointed to several meta-analyses which were consistent with the present findings.

One meta-analysis, which covered studies involving approximately 30,000 patients with coronary heart disease (CHD), found that people with CHD who were randomized to receive daily omega-3 supplements experienced a 10% reduced risk of all-cause mortality, an 18% reduced risk of cardiovascular mortality, a 23% reduction in myocardial infarction, a 33% reduced risk of cardiac death, and a 25% reduced risk of hospitalization for heart failure or unstable angina.

Another meta-analysis found that, in 150,000 members of the general population who didn’t have heart failure at baseline, omega-3s may have served as a preventive measure, reducing the risk of myocardial infarction by 13% and fatal myocardial infarction by 35%, compared to control.

“This new study by Jawad and colleagues provides powerful evidence that omega-3 fatty acids are protective against the development of heart failure, which is one of the most common causes of hospitalization in the U.S. today,” said William S. Harris, PhD, senior investigator of the present study, and president of the Fatty Acid Research Institute (FARI). “The medical profession needs to take seriously the long-term potential of these simple nutrients to address one of our major health challenges.”