Study Reveals Fish Oil Supplements May Increase Risk of Stroke and Atrial Fibrillation

HealthLine reports this, About 20% of adults over 60 in the United States regularly use fish oil supplements to support heart health. However, a new study indicates that these supplements may actually increase the risk of first-time stroke and atrial fibrillation (AFib) among people with good cardiovascular health.

Atrial fibrillation, or AFib, is an irregular heartbeat often described as a flutter or pounding sensation in the chest.

“I can see the headline for this study as ‘Fish oil supplements: Is it time to dump them or not?’” said Dr. Andrew Freeman, director of cardiovascular prevention and wellness at National Jewish Health in Denver. “Over-the-counter fish oil is very seldom recommended and is not included in professional medical guidelines, yet it’s what most people take,” said Freeman, who was not involved in the study.

Fish Oil Only Beneficial for Those with Existing Heart Disease

The study analyzed data from over 415,000 people aged 40 to 69 participating in the UK Biobank, a longitudinal study of health in the UK. Nearly one-third of participants, who were followed for an average of 12 years, reported regular use of fish oil supplements.

For individuals without heart issues, regular use of fish oil supplements was linked to a 13% higher risk of developing AFib and a 5% increased risk of stroke, according to the study published in the journal BMJ Medicine.

Over-the-counter fish oil suffers from issues of purity and consistency, and may contain contaminants and heavy metals such as mercury, Freeman noted. “Studies over the last 10 years have not been very positive for over-the-counter fish oil,” he said. “Fish oil has either shown no benefit or, in some cases, may cause harm, such as increasing the risk of stroke and AFib. So that’s not new.”

The study found that people with existing heart disease at the start of the research had a 15% lower risk of progressing from AFib to a heart attack and a 9% lower risk of progressing from heart failure to death when they regularly used fish oil. According to CNN

Prescription versions of fish oil, such as Vascepa and Lovaza, are used to manage risk factors like high triglycerides in people with cardiovascular disease, Freeman explained. However, even prescription-strength fish oil carries risks for AFib and stroke, so doctors remain cautious.

“Overall, the days of people buying buckets of fish oil pills to stay healthy should be over,” Freeman said, “but fish oil may still have a role for people who are already sick.”

Food Sources for Omega-3s Preferred

“The devil is in the details,” said Dr. Richard Isaacson, a preventive neurologist and director of research at the Institute for Neurodegenerative Diseases in Boca Raton, Florida, who was not involved in the study. “First, we recommend testing for omega-3 fatty acid levels—there are accurate finger-prick tests available online. You don’t want to take fish oil if you don’t need it.”

Isaacson recommends getting omega-3 fatty acids from food sources such as sardines and wild-caught salmon, which are high in omega-3s and low in mercury. He advises against farm-raised salmon due to impurities. Other good sources include lake trout, mackerel, herring, and albacore tuna, though consumption of tuna should be limited to twice a week due to mercury levels.

Non-fish sources of omega-3s include algae, seaweed, chia seeds, edamame, flaxseed, hempseeds, and walnuts. However, these plant-based omega-3s are a different form and may be harder to metabolize in people with high levels of omega-6s, another type of unsaturated fat found primarily in vegetable oils.

If Supplements Are Needed

Experts agree that prescription omega-3 fatty acids are superior to over-the-counter options due to their purity and quality. However, prescribed supplements can be expensive. For those opting for over-the-counter omega-3s, Isaacson provides these tips:

Freshness is key. “Buying from an online or retail superstore, such as Amazon or Costco, isn’t the best idea,” Isaacson said. “We recommend buying from reputable companies directly from their websites.” Fish oil stored in a hot warehouse and close to expiration is vastly different in quality from fish oil recently produced and kept in a home refrigerator. As Reported by The Hill

The US Food and Drug Administration does not monitor the supplement industry to ensure that each product contains what it claims or to test for contaminants such as bacteria, heavy metals, pesticides, plastic residues, and other impurities.

Some organizations, however, test various supplements and pharmaceuticals. Look for labels from these third-party testers before purchasing. The nonprofit US Pharmacopeia (USP) sets widely accepted standards for supplements, but ConsumerLab.com and NSF International also perform third-party testing.