From the Guidelines
Fish oil may increase the risk of atrial fibrillation (AFib) in certain individuals, particularly those taking high doses of prescription omega-3 fatty acid preparations, as evidenced by multiple randomized controlled trials 1. When considering the use of fish oil, it's essential to distinguish between nonprescription fish oil supplements and prescription omega-3 products. Nonprescription fish oil supplements are not regulated by the FDA to the same degree as prescription medications and may contain impurities, saturated fat, and oxidized lipids 1.
Key Points to Consider
- Prescription omega-3 fatty acid preparations, such as icosapent ethyl (IPE), have been shown to increase the risk of AFib in patients with elevated triglyceride levels and established cardiovascular disease or diabetes mellitus 1.
- The risk of AFib associated with fish oil supplements is more significant at higher doses, typically above 1.8 to 4 g daily 1.
- The American College of Cardiology recommends evaluating the potential net benefit of prescription omega-3 fatty acids in patients at high risk of AFib 1.
Recommendations for Use
- Patients with a history of heart problems or AFib should discuss the use of fish oil supplements with their healthcare provider to determine the appropriate dosage and potential risks 1.
- For general heart health, moderate fish oil consumption, such as eating fatty fish twice weekly or taking fish oil supplements containing 250-500 mg of combined EPA and DHA omega-3 fatty acids daily, may be beneficial 1.
From the Research
Fish Oil and Atrial Fibrillation
- The relationship between fish oil and atrial fibrillation (AF) is complex, with some studies suggesting a potential anti-arrhythmic effect, while others indicate a possible pro-arrhythmic effect 2.
- A study published in the International Journal of Cardiology found that intravenous omega-3 polyunsaturated fatty acids (ω-3 PUFAs) slowed atrial conduction and reduced the inducibility of AF, but increased the inducibility of atrial flutter 2.
- In contrast, a randomized clinical trial published in JAMA found that long-term administration of marine omega-3 fatty acids did not significantly reduce the risk of incident AF 3.
- Another study published in PLoS ONE found that dietary intake of fish and fish-derived n-3 fatty acids was not associated with AF risk, although higher levels of docosahexaenoic acid (DHA) were associated with a lower risk of AF 4.
Fish Oil Supplements and Atrial Fibrillation
- A prospective cohort study published in BMJ Medicine found that regular use of fish oil supplements was associated with an increased risk of AF, but may be beneficial for progression of cardiovascular disease from AF to major adverse cardiovascular events 5.
- However, a study published in medRxiv found that plasma omega-3 levels were inversely associated with incident AF, and that fish oil supplement use was not associated with AF risk after adjusting for age 6.
- The evidence suggests that the relationship between fish oil supplements and AF is complex and may depend on various factors, including the dose and duration of supplementation, as well as individual characteristics such as age and cardiovascular health 3, 5, 6.