Study confirms vitamin D, fish oil don't lower atrial fibrillation risk

A study published March 16 in JAMA (the Journal of the American Medical Association) confirms that neither vitamin D nor the omega-3 fatty acids found in fish oil prevent the development of atrial fibrillation (AF), a potentially serious heart rhythm disturbance. The newly published research follows a presentation made by Christine Albert, MD, MPH, at the American Heart Association Scientific Sessions last year.

In their JAMA analysis, Albert and her research team also examined whether vitamin D or omega-3 fatty acids might have an impact on paroxysmal versus persistent atrial fibrillation and whether there might be certain subgroups of patients who would be more likely to benefit or be harmed by the supplements. Overall, the results were mostly consistent across types of AF and groups of patients.

"Our recommendation remains the same," said Albert, chair of the Department of Cardiology in the Smidt Heart Institute and the Lee and Harold Kapelovitz Distinguished Chair in Cardiology. "We do not support taking fish oil or vitamin D supplements to prevent atrial fibrillation."

Albert added, "However, unlike other recent trials that found increased risks of atrial fibrillation with higher-dose omega-3 fatty acid supplements, our study did not find a significantly increased risk of atrial fibrillation with one gram of fish oil per day, which is good news for individuals taking low-dose fish oil for other health conditions."

Similarly, vitamin D supplements at 2,000 international units per day also did not increase AF risk.

Atrial fibrillation, commonly called Afib, is the most common type of abnormal heart rhythm, causing the heart to contract irregularly and, sometimes, too quickly. It is estimated to affect 33 million people worldwide.

The condition can lead to clotting inside the atrium chamber of the heart and clots can then travel from the heart to the brain, causing a stroke. Atrial fibrillation can also lead to weakening of the bottom chamber of the heart, resulting in fluid buildup or heart failure. Importantly, it often results in significant symptoms that can adversely affect one's quality of life.