By Randy Dotinga HealthDay Reporter
 

Putting a confusing twist on the health value of fish oil, a new study suggests that eating lots of fish may actually boost the risk of atrial fibrillation, a potentially dangerous heart condition, in certain people.

 

However, the heavy fish eaters in the study still had a lower risk of sudden death from heart problems, and the study's lead author said the research shouldn't stop anybody from eating fish.

 

In recent years, many doctors have urged patients to eat oily fish — such as mackerel, herring, albacore tuna and salmon — or take fish oil supplements. Both contain omega-3 fatty acids, which have been linked to better recovery from heart disease and a lower risk in older people of atrial fibrillation, in which the heart's electrical system malfunctions, and the muscle fails to beat in an orderly fashion.

 

But it's not entirely clear that omega-3 fats are good for the general population without heart disease. And some research has suggested they may actually boost the risk of atrial fibrillation in certain people, such as those younger than 60.

In the new study, researchers analyzed data from nearly 17,700 U.S. male doctors who took part in the Physicians' Health Study.

 

The men answered questions about their fish consumption in 1983 and were asked in 1998 if they had developed atrial fibrillation.

After adjusting the data to account for factors like existing heart disease, the researchers found that men who ate fish more than five times a week were 61 percent more likely to develop atrial fibrillation, compared to those who ate fish once a month. In total, about 7 percent of all the men in the study said they developed the condition, which is somewhat common among the elderly but rarer among younger people.

 

The findings were to be released Thursday at the Heart Rhythm Society's annual meeting, in Boston.

What could explain the seemingly contradictory finding?

It's possible that omega-3 fatty acids may actually promote the development of atrial fibrillation in younger people but prevent it in older people who have other medical conditions, said study author Dr. Anthony Aizer, an electrophysiologist at New York University Medical Center.