By Ernie Mundell
FRIDAY, Nov. 13, 2020 (HealthDay News) -- Millions of people take a fish oil or vitamin D supplement in hopes of warding off a host of ills. But a new study finds the nutrients won't shield against the common and potential heart rhythm disorder known as atrial fibrillation.
"A-fib" affects about 2.7 million Americans and can lead to complications such as blood clots, stroke and even heart failure. The risk of a-fib increases with age, high blood pressure and heavy drinking, and may be more common in some families.
The study results "do not support using marine omega-3 fatty acids or vitamin D to prevent atrial fibrillation," said lead author Dr. Christine Albert. She's founding chair in the Department of Cardiology at Cedars-Sinai Medical Center's Smidt Heart Institute in Los Angeles.
On the other hand, "the results do provide reassurance that these supplements do not increase the overall risk of atrial fibrillation and appear to be generally safe for patients who are taking these supplements for other reasons," Albert said in a news release from the American Heart Association.
Her team presented the findings today at this year's virtual annual AHA meeting.
According to the investigators, prior research hasn't provided clear answers on either the benefits or harms of vitamin D and omega-3 fatty acids when it came to a-fib.
This five-year study included more than 25,000 adults, 50 and older, with no prior history of a-fib. It sought to determine whether vitamin D3 supplements of 2000 IU/day or 840 mg/day of omega-3 fatty acids reduced the risk of developing the heart arrhythmia.
During the study, 3.6% of participants overall did go on to develop a-fib. But there was no statistically significant difference in risk for a-fib between people who took the omega-3 fatty acid supplements and/or vitamin D3 supplements versus those who took a placebo.
Dr. Mitchell Weinberg is chair of cardiology at Staten Island University Hospital in New York City. He wasn't involved in the new research, but said the findings came as "little surprise."
Weinberg believes many people place too much hope in the power of supplements to improve their health.
"The idea that taking more of a given vitamin will extend your life or confer significant added health benefits is very attractive to the health-conscious patient," he said.
But, "while a variety of benefits have been attributed to these two supplements, the scientific evidence is not strong enough to support routine high-dose supplementation," Weinberg added.
"While vitamin D is important for bone health, the claim that vitamin D supplementation decreases the risk for heart disease, cancer and diabetes is not very convincing," he said. "Similarly, the beliefs that omega-3 fatty acids decrease triglycerides, reduce inflammation and decrease mood-related disorders, are without sufficient evidence."
Weinberg's advice: "For now, patients should focus on eating healthy, exercising regularly and consistently following up with a health care professional."
Because the new findings were presented at a medical meeting, they should be considered preliminary until published in a peer-reviewed journal.
For more on a-fib, go to the U.S. National Heart, Lung, and Blood Institute.
SOURCES: Mitchell D. Weinberg, MD, chair, Department of Cardiology, Staten Island University Hospital, New York City; American Heart Association, news release, Nov. 13, 2020