Regular use of fish oil supplements may increase first time heart disease and stroke risk

Medical News Today Article Written by Bob Curley on May 23, 2024 — Fact checked by Sarah Myers, PharmD

Fish oil, a source of omega-3 fatty acids commonly used to reduce cardiovascular risk, might actually increase the risk of heart attack and stroke among people who have good cardiovascular health.

Researchers from China say they have found an association between use of fish oil supplements and heightened cardiovascular risk among heart-healthy individuals even as the study showed benefits of the supplements for those with poor cardiovascular health.

“These findings indicate that the recommendation of fish oil should be more selective and tailored to individual patient profiles,” said Dr. Adedapo Adeyinka Iluyomade, a preventative cardiologist with the Baptist Health Miami Cardiac & Vascular Institute in Florida who was not involved in the research.

“Fish oil may be more beneficial for patients with preexisting cardiovascular conditions rather than for primary prevention in the general population,” he told Medical News Today.

 

Details from the fish oil and heart health study

 

The study, which was published in the journal BMJ Medicine, was drawn from data on 415,737 people in the UK Biobank, about a third of whom took fish oil supplements.

Researchers reported that individuals with no known cardiovascular disease who regularly took fish oil supplements had a 13% higher risk of developing atrial fibrillation and a 5% higher risk of having a stroke than those who had good heart health but didn’t use fish oil.

However, researchers added that individuals who had cardiovascular disease and used fish oil supplements 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.

The risk of transitioning from good health to heart attack, stroke, or heart failure was 6% higher among women who took fish oil as well as 6% higher among non-smokers. The protective effect of fish oil on the transition from good health to death was greater in men and older study participants.

“Regular use of fish oil supplements might have different roles in the progression of cardiovascular disease,” the study authors wrote.

Iluyomade noted that fish oil supplements containing omega-3 fatty acids are widely used for cardiovascular risk reduction.

“Many patients take them for primary or secondary prevention of heart disease based on the belief they have cardiovascular benefits,” he said. “This usage is based on the idea that omega-3 fatty acids have anti-inflammatory properties and can help improve lipid profiles.”

“Omega-3 fatty acids lower triglyceride levels, decrease blood pressure, and reduce inflammation,” said Dr. Rohit Vuppuluri, a cardiologist at the Drs. Sawlani and Sukenik Group in Chicago who was not involved in the study. “However, when fish oil is recommended for medical treatment, it should be consumed using a prescription-grade fish oil rather than over the counter fish oil. This ensures the fish oil is medical grade quality.”

“Eating salmon regularly is also a great source for omega-3 fatty acids,” Vuppuluri told Medical News Today.

 

A mixed bag of research on fish oil supplements

 

Like the current study, past research on the benefits of fish oil has been mixed.

“While some studies and meta-analyses have suggested benefits, such as reduced risk of heart attack and sudden cardiac death, others have shown minimal or no significant impact on overall cardiovascular mortality,” said Iluyomade.

“This study is very interesting and the findings worthy of further exploration, but I still recommend that patients get at least 500mg [of] omega-3s per day, whether from eating fatty fish, taking an omega-3 supplement, or a combination of the two,” said Elana Natker, a registered dietitian and director of consumer and health professional communications for the Global Organization for EPA and DHA Omega-3s, an industry trade group.

“While this study was on a large population, it was observational in nature with potential confounding factors and no consideration of dose,” Natker, who was not involved in the research, told Medical News Today. “Meta-analyses of human clinical trials have found statistically significant reductions in hearth attack and death from heart attack and coronary heart disease.”

The study authors wrote that “further studies are needed to determine the precise mechanisms for the development and prognosis of cardiovascular disease events with regular use of fish oil supplements.”

Natker said that human clinical studies are needed to suggest a causal relationship between omega-3s and atrial fibrillation.

“While concerns have been raised about the effects of omega-3 fatty acids to increase the risk of atrial fibrillation, little or no increase has been seen with daily dosages less than one gram,” she said.

 

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