A new analysis published in the Journal of the American Heart Association found higher circulating blood levels of omega-3 fatty acids are associated with a significantly lower risk of developing atrial fibrillation (AFib).
The comprehensive biomarker-based study—one of the largest of its kind—analyzed data from hundreds of thousands of participants in the UK Biobank. Researchers showed that individuals with higher omega-3 levels had a lower incidence of AFib over a median of 12.7 years of follow-up, compared to those with lower omega-3 status.
Notably, when properly accounting for the confounding effects of age in statistical models, reported fish oil supplement use was not associated with an increased risk of AFib. This result contradicts previous reports from UK Biobank that “mistakenly concluded that fish oil supplements increase the risk for atrial fibrillation,” researchers said.
“These results reinforce that it’s the physiologic status of omega-3 in the blood—not simply supplementation per se—that correlates with AF risk. In properly adjusted models, supplement use showed no increase in AF risk,” said Dr. Bill Harris, President of the Fatty Acid Research Institute (FARI), and senior investigator on the paper.
The biomarker-based approach provided a more nuanced understanding than studies that rely solely on self-reported supplement usage or dose. It aligns with the broader body of evidence showing cardiovascular benefits of omega-3 fatty acids, researchers said.
“From a clinical standpoint, these findings help clarify an important misconception. When we look at objectively measured blood omega-3 levels, higher status is associated with lower risk of atrial fibrillation—not higher,” Harris said. “This reinforces the importance of evaluating physiology, not assumptions about supplements. Concerns raised by earlier reports linking fish oil use to atrial fibrillation were likely driven by methodological limitations. When age is modeled appropriately, fish oil supplement use does not increase atrial fibrillation risk.”
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