Eating fish has no effect on abnormal heart rhythm

NEW YORK (Reuters Health) - There are plenty of good reasons to eat fish, but preventing abnormal heart rhythms doesn't seem to be one of them, according to a new study.

Dr. Jarrett D. Berry of the University of Texas Southwestern Medical School in Dallas and his colleagues found no relationship between how much non-fried fish postmenopausal women ate and their risk of developing atrial fibrillation, the most common heart rhythm abnormality.

About a quarter of people will develop atrial fibrillation in their lifetimes, Berry and his team note in the American Journal of Cardiology. The condition occurs when the heart's two upper chambers, or atria, quiver rather than contracting rhythmically. This causes blood to pool in the atria rather than being pumped through the body efficiently, increasing the risk of blood clots and strokes.

There is evidence that omega-3 fatty acids, in fish or as supplements, could help reduce atrial fibrillation risk, Berry and his team write, but other studies have found no relationship.

To investigate, they looked at 44,720 participants in the Women's Health Initiative study, postmenopausal women 50 to 79 years old. During follow-up, which lasted around six years, 378 women, or less than 1 percent of the study participants, developed atrial fibrillation.

Fewer than 5 percent of the women ate five or more servings of fish a week; average fish consumption was 1.5 servings weekly. But the researchers found no relationship between how much fish women ate, or how much omega-3 fatty acid they consumed, and their atrial fibrillation risk.

Berry and his team conclude that their findings offer "no evidence" that omega-3 fatty acid or fish consumption affects the risk that a healthy postmenopausal woman will develop atrial fibrillation.

SOURCE: American Journal of Cardiology, online February 8, 2010.