Fish oil supplements, used during pregnancy and to improve cardiovascular and brain health, could increase the risk of heart problems and stroke, new research suggests.
A U.K. study published in the British Medical Journal on Tuesday found that the regular use of fish oil supplements was associated with an increased risk of stroke and atrial fibrillation, which is irregular heartbeat, in the healthy population.
However, taking these supplements could benefit people with a known cardiovascular disease, the study found.
“Regular use of fish oil supplements might have different roles in the progression of cardiovascular disease,” the authors wrote.
Researchers looked at data including more than 415,000 people aged 40 to 69 years between 2006 and 2021 in the United Kingdom.
Richard Bazinet, a professor in the department of nutritional sciences at the University of Toronto, said this is an “important study” which adds to a growing body of research that has signalled fish oil supplements potentially leading to atrial fibrillation in the general population.
“The disadvantage of this study is it’s what we call observational, so that means they didn’t randomize healthy and unhealthy people to get fish oil or a placebo group,” Bazinet said in an interview with Global News Friday.
“The other thing that this study points out is that not all fish oil supplements are the same,” he said.
“You can do a bit of homework and check to see if the supplement you’ve been taking has been quality checked for things like antioxidants and heavy metals, to make sure it’s a good source.”
The study authors acknowledged that more research is needed to determine how using fish oil supplements regularly could impact cardiovascular disease events.
What are the benefits of fish oil?
Fish oil supplements contain omega-3 fatty acids that could help with improving a person’s heart health by lowering blood pressure, fighting inflammation that can hurt blood vessels and decreasing triglycerides in the blood, according to the Mayo Clinic.
Omega-3s are also “extremely important” in brain development in infants and during pregnancy, Bazinet said.
While omega-3 fats are found in fish and even plant sources, supplements are a popular option, especially for those who don’t like to eat seafood.
The Heart and Stroke Foundation of Canada says that the best way to increase omega-3 intake is from the foods people eat.
“If you don’t eat fish, you may choose fortified foods like eggs, milk or margarine,” the foundation says on its website.
Flaxseeds, walnuts, pecans, chia, canola and soybean oil are some good plant-based sources for omega-3 fats.
Bazinet stressed the importance of a healthy diet to prevent heart disease. He cautioned against supplemental approaches, shortcuts or “biohacking” until more research is done on supplement use.
“People should focus on their diets and that’s the number one priority,” Bazinet said.
If people have concerns, he advised talking to a health professional, such as a dietician.