CHICAGO (AP) – Eating fish is good for the heart, but taking omega-3 fish oil supplements did not prevent flare-ups of a common heart rhythm problem as doctors hoped it would, researchers reported Monday.
It was the first large, well-done study to test omega-3 capsules for atrial fibrillation, when the heart quivers instead of beating normally. More than 2 million Americans have the problem, which is more than an unsettling flutter — it raises the risk of blood clots that can cause a stroke.
Small studies have gone back and forth on whether fish oil helps this condition. Researchers tested this by giving 663 people with atrial fibrillation either dummy pills or a high-dose prescription version of omega-3 fatty acids — the good fat in oily fish like salmon, tuna and sardines.
After six months, there was no difference in heart flutter episodes. Doctors say ordinary fish oil supplements that people buy at the store are even less likely to help this condition.
“This is data that we’ve needed sorely,” because so many people are taking supplements, said Dr. Christine Albert of Brigham and Women’s Hospital in Boston. “They showed no evidence of any benefit.”
The study’s leader, Dr. Peter Kowey, cardiology chief at Main Line Health Hospital System near Philadelphia, said many people take supplements and vitamins that have not been well tested.
“People are spending an enormous amount of money on stuff that doesn’t work,” he said.
Results were reported Monday at an American Heart Association conference in Chicago and published online by the Journal of the American Medical Association.
The capsules used in the study are sold as Lovaza in the United States and as Zodin in Europe by GlaxoSmithKline PLC, which paid for the research.
A lot of research suggests that eating fish helps protect against heart disease, and the Heart Association recommends adults eat fish at least twice a week. People with heart disease — clogged arteries — who cannot get enough omega-3 from dietary sources should talk with their doctors about supplements, the association says.
No one should consume more than 3 grams of omega-3 without direction from their doctor, the association says. Fish oil capsules are not for children or women who are pregnant or nursing, because they can cause bleeding problems.
Earlier this month, a big study found that omega-3 pills didn’t slow the mental or physical decline of Alzheimer’s disease patients. The pills in that study had omega-3 derived from algae.
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