Fish Oil Supplements Could Increase Risk of Atrial Fibrillation: Study

Researchers warn that individuals should not stop taking omega-3 fish oil supplements until they talk to their doctor about the risk of abnormal heart rhythms.

Individuals who take omega-3 supplements, commonly found in fish oil, may face an increased of experiencing abnormal heart rhythms, according to the findings of a new study.

Researchers with the Harvard T. H. Chan School of Public health warn that side effects of fish oil supplements may result in rapid or irregular heartbeats, leading to a condition known as atrial fibrillation, which can increase the risk of strokes. Their findings were published October 6, in the medical journal Circulation.

Atrial fibrillation is a heart condition where a person suffers abnormal heart rhythm, either rapid or irregular heartbeats. It often begins as short bursts of abnormal heart beating which become longer, more pronounced, or persist over time. Some patients experience it as a heart flutter at first, which later progresses to more severe symptoms. Patients can experience heart palpitations, fainting, lightheadedness, shortness of breath, or chest pain. Initially, the condition is harmless, but it can eventually lead to heart failure, stroke, and even dementia.

The researchers analyzed studies in MEDLINE and Embase databases for research published from 2012 to 2020. They also included a meta-analysis of randomized control trials published in 2019, resulting in data on more than 81,000 patients from seven trials.

Nearly 59,000 patients enrolled in clinical trials took less than one gram per day of omega-3 fatty acids from fish oil supplements. Roughly 22,000 patients in clinical trials took more than one gram per day of omega-3 supplements.

According to the findings, taking fish oil supplements in a dose greater than one gram per day are linked to a higher risk compared to taking less than one gram per day.

During the study, approximately 3.6% of participants developed atrial fibrillation. The risk of atrial fibrillation increased for each one gram increase of omega-3 fatty acids taken. Taking one gram or more of fish oil increased the risk of a-fib by 49%. Those taking less than one gram had an increased risk of a-fib of 12%.

Fish is widely considered a heart-healthy food, but other studies have also linked omega-3 fatty acids in supplement form to increased risk of atrial fibrillation as well.

Prescription strength omega-3 fatty acids, like Vascepa and Lovaza, are often prescribed to patients with high cholesterol. Vascepa is prescribed in 0.5 gram capsules, often in a dose of four or more grams per day, which is higher than the one gram dose that increases the risk of a-fib.

The researchers recommended patients taking omega-3 supplements not immediately stop taking them, whether prescription or over-the-counter. They should talk to their doctor about their potential risk of atrial fibrillation first. They should also be aware of potential symptoms, including dizziness and rapid heartbeat, the researchers warned.

Researchers suggested trying to get as much omega-3 fatty acids from fish and not supplements. Two servings per week of fish like salmon, albacore tuna, and trout can offer sufficient omega-3 fatty acids.