Omega-3 supplements could increase your risk of atr


Image: New research from the Smidt Heart Institute shows that more than 1 gram of fish oil per day can increase the risk of atrial fibrillation.
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Credit: Photo by Cedars-Sinai

Los Angeles (October 6, 2021) –

Atrial fibrillation is the most common type of arrhythmia that causes the heart to contract irregularly and sometimes too quickly. It is estimated that 33 million people worldwide are affected and can lead to blood clots, stroke, heart failure, and other heart-related complications.

According to the 2012 National Health Interview Survey, an estimated 7.8 percent of American adults, nearly 19 million people, take fish oil supplements.

Recent research conducted by Christine M. Albert, MD, MPH, Professor of Cardiology and Chair of the Department of Cardiology at the Smidt Heart Institute, found that neither vitamin D nor the omega-3 fatty acids found in fish oil promote atrial development prevent flicker. However, other clinical studies conducted outside of Cedars-Sinai indicated an increased risk of developing atrial fibrillation in omega-3-treated patients, which confused doctors and patients alike.

To further explore the possible reasons for differences between the results of these studies, Albert and his team performed a meta-analysis that combined the results of several scientific studies. This analytical comparison between the studies indicated that the risk of developing atrial fibrillation depends on the dose of omega-3 fatty acids.

While there is strong evidence that omega-3s can significantly lower blood triglyceride levels and arthritis pain, most experts agree that it is best to eat omega-3s several times a week.

“Our goal was to provide clarity, answers, and actionable information to the broader medical community and patients,” said Albert, the Lee and Harold Kapelovitz Distinguished Chair in Cardiology. “In this case, the results suggest that there may not be a simple answer to the question, ‘Is fish oil good or bad for atrial fibrillation?’ but instead the answer may depend on the dose. “


The main highlights of the research study include:

  • Data from 81,210 patients who participated in seven clinical trials were reviewed, including one in Cedars-Sinai. The mean age of the patients included in these studies was 65 years and 39% were women.
  • Of these patients, 72.6% participated in clinical trials that tested less than or equal to 1 gram of omega-3 fatty acids per day, and 27.4% participated in clinical trials that tested more than 1 gram of the dietary supplement were tested per day.
  • Patients who took more than one gram of omega-3 fatty acids per day had a 49% increased risk of developing atrial fibrillation, compared with only 12% of patients who took one gram or less of the supplement per day.

Treatment recommendations

Armed with this information, Albert now has recommendations for clinicians, researchers, and patients.

When offering high-dose omega-3 fatty acid supplements, doctors should first discuss the potential risk of developing atrial fibrillation and educate patients about the possible signs and symptoms of the condition so that an early diagnosis can be made and coupled with appropriate treatment.

Researchers, Albert says, should systematically monitor patients for atrial fibrillation and associated side effects to better define the risk-benefit balance in studies examining the effects of omega-3 fatty acid supplements.

“For patients, the risk of developing atrial fibrillation seems to be relatively small if they take a gram or less of fish oil a day,” said Albert. “Ingesting more than one gram of fish oil a day is something you should only do on the advice of your doctor.”

The study, which combined previously published results, failed to determine whether there are patients who are more prone to developing atrial fibrillation when taking fish oil.

The risk of developing atrial fibrillation increases with age and is more common in men than women. In addition to age and gender, other risk factors include high blood pressure, coronary artery disease, heart failure, heart valve defects, obesity and diabetes.

The condition is also more likely to occur during an infection or right after surgery. Stress, caffeine, and alcohol can also trigger seizures. People who do a lot of repetitive, vigorous endurance exercise, such as marathons, can also develop atrial fibrillation. How fish oil can alter the risk of atrial fibrillation in marathon runners or in people with other risk factors is still unknown.

Read more on the Cedars Sinai Blog: Hypertension: What Women Need to Know

Research method


Research subject


Article heading

Effect of long-term marine omega-3 fatty acid supplementation on risk of atrial fibrillation in randomized controlled trials of cardiovascular outcomes: a systematic review and meta-analysis

Publication date of the article

October 6, 2021

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