(HealthDay)—High doses of fish oil supplements won't prevent recurrence of atrial fibrillation (AF), Canadian researchers report. The study, funded by the Canadian Institutes for Health Research and the Heart and Stroke Foundation of Quebec, was published in the Oct. 7 issue of the Journal of the American College of Cardiology.

Anil Nigam, M.D., from the University of Montreal, and colleagues randomly assigned 337 patients with AF to 4 grams of fish oil a day or to a placebo. The patients were followed for up to 16 months. The primary end point was time to first symptomatic or asymptomatic AF recurrence lasting more than 30 seconds. Secondary end points were levels of high-sensitivity C-reactive protein and myeloperoxidase, for the assessment of inflammation and oxidative stress.

The researchers found that 64.1 percent of those taking the fish oil supplements experienced recurrence of AF over the course of 16 months, compared to 63.2 percent of those taking a placebo. Fish oil supplements also did not reduce inflammation or , which may explain why they didn't guard against AF, the study authors noted.

"Fish oil has no role to play in the treatment of ," Nigam told HealthDay. "However, people with poor heart function might still benefit from taking ," 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."