Fish oil for a-Fib

Despite its reputation as a heart-healthy supplement, more than a certain amount of omega-3 fish oil taken every day may actually increase the risk of a common heart arrhythmia, a recent study found. (Source: Adobe Stock)

Atrial fibrillation, or AFib, is the most common type of abnormal heart rhythm, estimated to affect between 2 and 6 million adults in the U.S. AFib causes the heart to contract irregularly or too quickly, which can lead to blood clots, stroke and other heart-related complications.

At the same time, an estimated 7.8% of American adults – roughly 19 million people – take a daily fish oil supplement, many at the recommendation of their doctors and generally based on the belief that the omega-3 fatty acids they contain can benefit their heart health.

Researchers at the Cedars-Sinai Smidt Heart Institute in Los Angeles recently looked into some confusing findings around AFib and omega-3s. They led an analysis of several studies that found not only do omega-3 supplements not prevent the development of AFib … they might actually increase the risk of developing it for some.

They examined data from seven clinical trials involving more than 82,000 patients. Their average age was 65, and 39% were women. About 73% were taking omega-3 supplements at a dosage of less than or equal to 1 gram (1000 milligrams), while the remaining 27% were testing more than 1 gram per day.

Their key finding was that patients who took more than 1 gram per day of omega-3 fatty acids had a 49% increased risk of developing AFib, compared to just 12% of patients who took 1 gram or less of the supplement per day.

“Our goal was to bring clarity, answers and actionable information to the broader medical field and to patients,” said Christine Albert, M.D., MPH, chair of the Smidt Institute’s Department of Cardiology. “In this instance, the results suggest that there may not be a straightforward answer to, ‘Is fish oil good or bad for atrial fibrillation?’ but instead, the answer may depend on the dose.” 

Albert suggested that healthcare providers who offer high-dose omega-3 fatty acid supplements to patients should first discuss the potential risk of developing AFib, and patients should also be informed about its potential symptoms so an early diagnosis can be made.