From the Guidelines
Fish oil supplements can increase the risk of atrial fibrillation, particularly at higher doses, as evidenced by multiple randomized controlled trials showing a dose-dependent association between omega-3 fatty acid supplementation and the development of atrial fibrillation 1.
Key Findings
- The risk of atrial fibrillation is higher with prescription omega-3 fatty acid preparations, especially at doses of 1.8 to 4 g daily, with studies such as REDUCE-IT, OMEMI, and STRENGTH trial demonstrating an increased risk of AF with therapy 1.
- Nonprescription fish oil products are not interchangeable with prescription omega-3 products and have not been demonstrated to have cardiovascular outcomes benefits, with variable content and quality, and potential impurities 1.
- The mechanism behind the association between omega-3 fatty acid supplements and atrial fibrillation may involve the effects of these fatty acids on the electrical properties of heart cells.
Recommendations
- If you're currently taking fish oil supplements and have risk factors for heart rhythm problems, such as existing heart disease, high blood pressure, or are elderly, you should discuss this with your healthcare provider to consider limiting your dosage to no more than 1 gram daily or alternative sources of omega-3 fatty acids through diet rather than supplements 1.
- Patients should be aware of the potential symptoms of atrial fibrillation, such as heart palpitations, shortness of breath, or dizziness, and seek medical attention promptly if they experience these symptoms while taking fish oil supplements.
Important Considerations
- The treatment of elevated triglyceride levels and reduction of ASCVD risk should be guided by the use of prescription omega-3 fatty acid products, such as IPE, which have been approved by the U.S. Food & Drug Administration for these indications 1.
- Clinicians should evaluate the potential net benefit of prescription omega-3 fatty acids in patients at high risk of AF, considering the consistency of findings from multiple randomized controlled trials 1.
From the Research
Fish Oil Supplements and Atrial Fibrillation
- The relationship between fish oil supplements and atrial fibrillation is complex, with some studies suggesting a potential link between the two, while others indicate no significant association 2, 3.
- A 2024 prospective cohort study found that regular use of fish oil supplements may be a risk factor for atrial fibrillation and stroke among the general population, with a hazard ratio of 1.13 (95% confidence interval 1.10 to 1.17) for the transition from healthy status to atrial fibrillation 2.
- However, another study published in 2011 found that supplementation with dietary fish oil did not result in a significant decrease in the incidence of postsurgical atrial fibrillation, although there was a significant decrease in time spent in the intensive care unit 3.
- A 2016 retrospective study found that fish and krill oil supplementation did not significantly alter warfarin time in therapeutic range (TTR) or bleeding incidence in patients with atrial fibrillation and deep vein thrombosis 4.
Risk Factors for Atrial Fibrillation
- A 2018 cohort study based on longitudinal data from the Framingham Heart Study found that individuals with at least one elevated risk factor were associated with at least 37.8% lifetime risk of atrial fibrillation, compared to 23.4% with an optimal risk profile 5.
- The study also found that the lifetime risk of atrial fibrillation was 33.4% with a borderline risk profile, and 38.4% with an elevated risk profile 5.
Bleeding Risk and Atrial Fibrillation
- A 2021 substudy found that a perceived high risk of bleeding was the most common reason for withholding anticoagulation for stroke prevention in atrial fibrillation, although median HAS-BLED scores were similar in patients deemed high-risk and those who were not 6.
- The study also found that nearly 12% of patients deemed high-risk for bleeding were ultimately prescribed anticoagulation by 90 days, with similar frequencies of major and clinically-relevant non-major bleeding between the groups 6.