Atrial fibrillation: high levels of Omega 3 reduce risk by 29%

According to a study published in Circulation by a group of researchers led by Dariush Mozaffarian, an expert at the Harvard School of Public Health (Boston, USA), high levels of Omega 3 in the blood reduce the risk of atrial fibrillation by 29 percent. Exerting the greatest beneficial effect against this disorder would be docohexaenoic acid (DHA), i.e., one of the two forms of Omega 3 found in fish and, more generally, in marine-derived sources of Omega 3. 

Omega 3 for heart health

Atrial fibrillation is the most common form of cardiac arrhythmia: more than 6 million people in Europe suffer from it. Its incidence increases with age; other risk factors include high blood pressure, diabetes, cardiac ischemia, congestive heart failure and left atrial hypertrophy (i.e., enlargement, in the heart, of the left atrium). It often appears after heart surgery. 

There are limited therapies available to address this issue. Given its widespread prevalence in increasingly older societies and its possible serious complications (such as stroke and heart failure) finding effective strategies to prevent it is especially important. 

Within this framework, Mozaffarian and colleagues decided to analyze the potential of Omega 3, fatty acids known as valuable allies of heart health. Specifically, years of research have associated these fats with:

• The ability to keep blood triglyceride levels under control;
• The ability to normalize blood pressure;
• Antithrombotic and anti-inflammatory properties;
• Reducing the risk of cardiovascular events, such as heart attack.

Atrial fibrillation: with omega-3 fatty acids, the heartbeat is more regular

The research involved analysis of data on 3,326 U.S. men and women at least 65 years old. At the beginning of the study, none of the participants had atrial fibrillation; during the research, scientists recorded the development of the condition in 789 individuals. They found that participants with the highest blood levels of Omega 3 and DHA had run an approximately 25 percent reduced risk of developing atrial fibrillation. 

Considering only total Omega 3 levels, higher amounts were found to be associated with a 29% reduction in risk, and reasoning in terms of percentage of total fatty acids, each 1% increase in Omega 3 levels was associated with a 9% reduction in risk of atrial fibrillation. 

Focusing instead on individual omega 3s, the association was specific for DHA, with a 23% reduction in risk. Each 0.5 percent increase in DHA levels over total fatty acids was associated with a 6 percent reduced risk of atrial fibrillation. 

The other two Omega 3s analyzed-EPA (eicosapentaenoic acid) and DPA (docosapentaenoic acid)-were not found to be associated with reduced risk of atrial fibrillation.

Omega 3 for the prevention of atrial fibrillation?

"Our results provide evidence that food-derived omega-3 fatty acids may protect against the development of atrial fibrillation at older ages," Mozaffarian and collaborators wrote in the pages of Circulation. 

The main source of these fats is fish. In addition, the market offers a wide range of dietary supplements containing DHA, either alone or in combination with EPA; the possibility of using them not only as a preventive approach to cardiovascular disease, but also in the prevention of atrial fibrillation has aroused strong interest in the medical-scientific community and would represent concrete benefits both for people's quality of life and from an economic point of view.

Unfortunately, however, the research conducted has produced mixed results. Even larger and longer placebo-controlled studies have found an increased incidence of atrial fibrillation dependent on the dose of Omega 3 taken.

Omega 3 drugs and risk of atrial fibrillation

In the case of drugs based on Omega 3 ethyl esters, prescribed for reducing blood triglycerides, the Italian Medicines Agency (Aifa) has issued a note agreed with European regulatory authorities to inform physicians about the association between their intake and the risk of atrial fibrillation.

The note confirms that this association is dose-dependent and that the risk "was highest with a dose of 4 g/day [grams per day]." In contrast, this risk was lower for lower doses as low as 1 gram/day.

In addition, the note specifies that increased risk has been observed "in patients with established cardiovascular disease or cardiovascular risk factors treated with omega-3 acid ethyl ester drugs," without mentioning risks for people in good health or without cardiovascular risk factors. The recommendation is to "seek medical attention if [you] develop symptoms of atrial fibrillation" and, if so, discontinue treatment permanently.

It is good to remember that symptoms of atrial fibrillation include dizziness, fatigue, palpitations, and respiratory problems, and that not all Omega supplements contain these fats in the form of ethyl esters; rather, today's better quality products focus on other, more natural forms, particularly re-esterified triglycerides and phospholipids.

How to deal with it?

Consuming adequate doses of Omega 3 sources, such as oily fish, continues to be important in meeting the body's needs, and Omega 3 supplements continue to be valuable health allies in cases where this is not possible or it is difficult to achieve the recommended intake (e.g., due to food selectivity, allergies, ethical choices, or increased needs). 

Keeping in mind Aifa's guidance on the risk of atrial fibrillation is important. From this perspective, choosing forms other than ethyl esters may be preferable. In any case, fortunately, it is often not necessary to reach the doses that have been associated with a high increase in risk.

Bibliographic references:

Herrmann W, Herrmann M. n-3 fatty acids and the risk of atrial fibrillation, review. Diagnosis (Berl). 2024 May 9;11(4):345-352. doi: 10.1515/dx-2024-0077

IMPORTANT INFORMATION NOTE AGREED WITH EUROPEAN REGULATORY AUTHORITIES AND THE ITALIAN MEDICINES AGENCY (AIFA). 8 novembre 2023. https://www.aifa.gov.it/documents/20142/1804929/2023.11.08_NII_omega-3_IT.pdf

Wu JH, Lemaitre RN, King IB, Song X, Sacks FM, Rimm EB, Heckbert SR, Siscovick DS, Mozaffarian D. Association of plasma phospholipid long-chain ω-3 fatty acids with incident atrial fibrillation in older adults: the cardiovascular health study. Circulation. 2012 Mar 6;125(9):1084-93. doi: 10.1161/CIRCULATIONAHA.111.062653