Omega-3 supplements may be associated with an increased likelihood of developing atrial fibrillation.

Omega-3 supplements may be associated with an increased likelihood of developing atrial fibrillation.

Some clinical trials have suggested that omega-3 fatty acids may be associated with an increased risk for atrial fibrillation (AF), the most common heart rhythm disorder in people with high blood lipids and high risk of cardiovascular disease. AF it is associated with high morbidity and mortality, ultimately making it a major public health burden (1).

 In this meta-analysis, the study that had the highest incidence of AF was a large placebo-controlled trial of 8,179 patients given a very high dose of highly purified icosapent ethyl N3 fatty acid

Although there was an increase in AF in the supplemented icosapent ethyl group among patients with elevated triglyceride levels and despite the use of statins, the risk of ischemic events, including cardiovascular death, was significantly lower among those who received 2 g of icosapent ethyl twice daily than among those who received placebo(2).

In another study included in the meta-analysis providing data on 125,763 patients also found a small increase of AF but a lower risk of cardiac death, myocardial infarction and lower rate of unstable angina versus controls(3).

Again a (2020) study of 427,678 men and women aged between 40 and 69, found that fish oil supplements were associated with a 13% lower risk of all-cause mortality, a 16% lower risk of CVD mortality, and a 7% lower risk of CVD events (388 fewer all-cause deaths, 124 fewer CVD deaths, and 295 fewer CVD events per 100,000 people in a median follow-up of 9 years the conclusion stated that habitual use of fish oil seems to be associated with a lower risk of all cause and CVD mortality and to provide a marginal benefit against CVD events among the general population(5)

This increase in AF needs further evaluation as the relationship of n3 fatty acids and this increase is unknown.

Importantly n3 fatty acids are essential to life and must be obtained from the diet. The positive effects of omega three fatty acids, although they may increase the risk of AF in high-risk patients with elevated lipids, they were found to reduce the incidence of CVD, ischemic events and cardiovascular death(1)(2)(3)(4) and as other studies have found regular supplementation with fish oil has been found to improved biomarkers of cardiovascular and cerebrovascular function(6).

The many benefits of omega3 fatty acids need to be considered against any possible adverse findings in high risk patients.

1.      European Heart Journal - Cardiovascular Pharmacotherapy, 2021

2.      N Engl J Med 2019;380:11–22

3.      Curr Atheroscler Rep 2020;22:45.

4.      Lancet 1999; 354:447–455

5.      BMJ 2020;368:m4561.    

6. Nutrition, Metabolism and Cardiovascular Diseases, Volume 30, Issue 4, 12 April 2020, Pages 625-633