TUESDAY, Sept. 30, 2014 (HealthDay News) -- High doses of fish oil supplements won't prevent the return of a common type of irregular heartbeat known as atrial fibrillation, Canadian researchers report.
In fact, 64.1 percent of those taking fish oil for its omega-3 fatty acids experienced new bouts of atrial fibrillation over the course of 16 months, compared to 63.2 percent of those taking a placebo. Fish oil supplements also did not reduce the twin ills of inflammation or oxidative stress, which may explain why they didn't guard against atrial fibrillation, the study authors noted.
"Fish oil has no role to play in the treatment of atrial fibrillation," said lead researcher Dr. Anil Nigam, an associate professor in the department of medicine at the University of Montreal.
Atrial fibrillation is a common malady in which the heartbeat is irregular and can race as fast as 150 beats a minute. A normal heart rate is around 70 beats a minute.
For the study, Nigam and his colleagues randomly assigned 337 patients with atrial fibrillation who were not being treated with medications to prevent the abnormal heart rhythm to 4 grams of fish oil a day or to a placebo. The patients were followed for up to 16 months.
The study, funded by the Canadian Institutes for Health Research and the Heart and Stroke Foundation of Quebec, was published online Sept. 29 in the Journal of the American College of Cardiology.
According to the Heart Rhythm Society, 2.7 million Americans suffer from atrial fibrillation, and that number is likely to increase as the population ages. The condition increases the risk of stroke fivefold and is responsible for 88,000 deaths each year.
Certain risk factors are associated with the development of atrial fibrillation, including obesity, high blood pressure, diabetes and sleep apnea, Nigam said. Some heart conditions, such as heart failure and heart valve problems, can also increase the risk of atrial fibrillation.
"For most people without heart problems, we believe a healthy weight and healthy lifestyle, and a good control of risk factors, can probably help reduce the risk of developing this condition, although this has not been studied per se," Nigam said.
He added that recent studies have found no benefit from fish oil supplements in people with heart disease who are being optimally treated and whose heart is working normally.
"However, people with poor heart function might still benefit from taking fish oil supplements," Nigam said. "What is better and should be recommended is a Mediterranean-type diet rich in natural omega-3 fats and other nutrients, including fresh fruits and veggies, legumes, olive oil, while lowering intake of red meat, trans fats and saturated fats," he said.
Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles, said, "While some studies of omega-3 fatty acid supplementation have shown a modest benefit in treating patients with heart failure, there appears to be no benefit with omega-3 fatty acids in treating atrial fibrillation."
For patients with atrial fibrillation, prescribing traditional medications to prevent this abnormal heartbeat is the most common treatment. Patients may also need to take a blood thinner to help reduce the risk of stroke, he said.
In addition, some patients can benefit from a procedure called catheter ablation, which in essence, burns tiny sections of the heart to prevent the recurrence of atrial fibrillation, Fonarow added.
Preventing atrial fibrillation in the first place is a challenge, and much more research is needed, he noted.
Visit the American Heart Association for more on atrial fibrillation.