AS an excellent source of heart-healthy omega-3 fatty acids, daily fish oil supplements are a popular way to keep the risk of cardiovascular disease at bay.

However, a new study finds regular use of fish oil supplements may increase, not reduce, the risk of first-time stroke and atrial fibrillation among people in good cardiovascular health.

Atrial fibrillation, also called AFib or AF, is a type of arrhythmia, or irregular heartbeat, that people often describe as a flutter or pounding in their chests.

“I can see the headline for this study as ‘Fish oil supplements: Is it time to dump them or not?’” said cardiologist Andrew Freeman, director of cardiovascular prevention and wellness at National Jewish Health in Denver, the United States.

“I say that because over-the-counter fish oil is very seldom recommended, is in none of the guidelines from professional medical societies, and yet that’s what most people take,” said Freeman, who was not involved in the study.

The study analyzed data on over 415,000 people ages 40 to 69 participating in the U.K. Biobank, a longitudinal study of the health of people in the United Kingdom. Nearly one-third of those people, who were followed for an average of 12 years, said they regularly used fish oil supplements.

For people without heart issues, regular use of fish oil supplements was associated with a 13% higher risk of developing atrial fibrillation and a 5% heightened risk of having a stroke, according to the study, published Tuesday in the journal BMJ Medicine.

Over-the-counter fish oil suffers from a lack of purity and consistency, as well as the potential contaminants and heavy metals such as mercury that come with fish, Freeman said.

In fact, the new study found that people with existing heart disease at the beginning of the research had a 15% lower risk of progressing from atrial fibrillation to a heart attack and a 9% lower risk of progressing from heart failure to death when they regularly used fish oil.

Instead, prescription versions of fish oil, such as Vascepa and Lovaza, are used to counter such risk factors such as high triglycerides, a type of blood fat, in people with cardiovascular disease risk, Freeman said.

“But even in the prescription strength, highly purified versions of fish oil, the risk for AFib and sometimes stroke has also been present and doctors are cautious about that,” Freeman said.

”Overall, I would say that the days where people just go to the store and buy buckets of fish oil pills to keep them well should be over, but fish oil may still have a role in people who are already sick.”

When it comes to fish oil, “the devil is in the details,” said Alzheimer’s preventive neurologist Dr. Richard Isaacson, director of research at the Institute for Neurodegenerative Diseases in Boca Raton, Florida. He was not involved in the study.

“First, we recommend testing for omega-3 fatty acid levels — there are finger-prick tests you can buy online which are accurate — and then you should continue to test. You don’t want to take fish oil if you don’t need it,” he said.

Isaacson recommends trying to get your omega-3 fatty acids from food sources and says sardines and wild-caught salmon are the best sources, as they are high in these healthy unsaturated fats and lower in mercury. Farm-raised salmon is not the best choice, he said, due to impurities in the water in which they are raised.

Lake trout, mackerel, herring and albacore tuna are also good sources, he said. However, due to the mercury levels in large fish such as tuna, he recommends consumption of albacore tuna should be kept to twice a week.

(SD-Agencies)