Why People at Risk of Heart Disease May Want to Avoid Fish Oil

Why People at Risk of Heart Disease May Want to Avoid Fish OilShare on Pinterest
A new study looks at the risk of taking omega-3 supplements for people with high risk of heart disease. Getty Images
  • New research finds that taking omega-3 supplements is associated with an increased risk of atrial fibrillation in people with a high risk of, or existing, heart disease.
  • Experts say the relationship between using omega-3 supplements and heart health is complicated.
  • Talk with your doctor about your risks and what is best for you.

While previous research found strong evidence that omega-3 fatty acids benefit heart health, this popular supplement may also carry a significant risk for some people.

According to a new analysis by the European Society of Cardiology, omega-3 fatty acid supplements are associated with an increased likelihood of developing atrial fibrillation (AFib) in people with high triglyceride levels.

Triglycerides are a type of fat found in the blood.

“Currently, fish oil supplements are indicated for patients with elevated plasma triglycerides to reduce cardiovascular risk,” study author Salvatore Carbone, PhD, of Virginia Commonwealth University said in a statement.

“Due to the high prevalence of elevated triglycerides in the population, they can be commonly prescribed,” he added.

The new analysis looked at five randomized controlled trials and investigated the effects of omega-3 fatty acid supplementation on cardiovascular outcomes.

Study participants had high triglyceride levels. They were at elevated risk of cardiovascular disease or had already received a diagnosis of it.

More than 50,000 participants were given fish oils (a source of omega-3s) or a placebo. Researchers followed them up for up to 7.4 years. The dosage of fish oil was between 0.84 grams and 4 grams daily.

Researchers found that omega-3 fatty acid supplementation was associated with significantly increased risks of AFib compared with a placebo.

“Atrial fibrillation is an arrhythmia, abnormal heart rhythm, characterized by irregular electrical activity in the top chamber of the heart, the left atrium,” Dr. Michael Goyfman, director of clinical cardiology at Long Island Jewish Forest Hills in New York, told Healthline.

“While some people may feel [heart] palpitations in the setting of atrial fibrillation, others have no symptoms,” he said.

Goyfman added that the main concern with AFib is the risk of a stroke or other thromboembolic event, in which a blood clot may form in the heart and then break off and travel to the brain or other organs.

“To decrease this risk, blood thinners are often prescribed to patients with AFib at higher risk of stroke,” Goyfman said.

Omega-3s are essential fats that the body needs to stay healthy.

According to the National Institutes of Health, omega-3s aren’t produced in the body. We have to consume them to maintain healthy levels.

Omega-3s come in three types:

  • alpha-linolenic acid (ALA)
  • eicosapentaenoic acid (EPA)
  • docosahexaenoic acid (DHA)

The National Institutes of Health emphasizes that omega-3s are an important part of the membranes that surround each cell in our bodies.

Levels of DHA are especially high in the eyes, brain, and sperm cells, and play an important role in many bodily functions.

Goyfman confirmed that for healthy people who consume omega-3s as part of a diet like the Mediterranean diet, “the incidence of cardiovascular events was significantly decreased.”

A 2019 science advisory published in the journal Circulation said 4 grams per day of prescription omega-3s can lower triglyceride levels by 20 to 30 percent in most people.

But how important is reducing these levels?

“Triglycerides are a type of fat in our bodies, and their levels are measured with a blood test similar to other fats such as HDL, the ‘good’ cholesterol, and LDL, the ‘bad’ cholesterol,” Goyfman said.

“While there has been some association between high triglyceride levels and cardiovascular disease, causality has never been established,” he said, “and we currently do not use triglyceride levels to calculate someone’s risk of stroke or heart attack.”

Asked whether the benefits of omega-3 supplements for healthy people outweighed their potential risks, Dr. Laurence M. Epstein, system director of electrophysiology at Northwell Health’s Sandra Atlas Bass Heart Hospital in New York, said it’s “unclear.”

“This remains controversial and is why this study was done,” Epstein said. “Some have claimed that they can lower the risk of coronary artery disease by affecting lipids such as triglycerides. Others have suggested that they can reduce the risk of life threatening heart rhythm problems.”

Epstein emphasized the importance of telling your doctor what supplements you’re taking.

“It is crucial that patients let their doctors know all the supplements they are taking,” he said. “This study suggests if you have atrial fibrillation, perhaps you should avoid these supplements.”

“The REDUCE-IT trial showed that patients with high triglycerides who took specific prescription-only omega-3 supplements had decreased risk of cardiovascular events including cardiovascular death,” Goyfman said. “As such, this is a complex question to address.”

According to Goyfman, AFib can be treated with appropriate medications, procedures, or both. The risk of stroke can be reduced with taking blood thinners.

“Some might argue that a reduction in death outweighs the risk of developing atrial fibrillation,” Goyfman said.

“On the other hand,” he cautioned, “people who are not in a category where they may benefit from omega-3 supplementation may be taking on unnecessary risk of developing atrial fibrillation.”

Goyfman said it’s important to keep in mind there are different types of omega-3s.

“Only EPA was used in the REDUCE-IT trial, and a mixture of EPA and DHA was used in the STRENGTH trial, which showed no benefit,” he said.

“Arguably, if different compounds were used, are we comparing apples to oranges?” Goyfman said.

Until further studies are done on specific types and dosages of omega-3s, Goyfman “would not recommend for patients to make a decision to either stop or start omega-3 supplementation without speaking with their physician.”

Epstein added that many supplements are poorly regulated, often have no warnings, and should be better regulated in general.

New research finds that taking omega-3 supplements is associated with an increased risk of atrial fibrillation in people with a high risk of, or existing, heart disease.

Experts say while omega-3s are essential for health, the relationship between using these supplements and heart health is complicated.

They also say that supplements in general are poorly regulated. It’s best to speak with your doctor before including omega-3s supplements in your diet.