Fish oil supplements, widely used for their heart-healthy omega-3 fatty acids, are a popular method to reduce the risk of cardiovascular disease. Approximately 20% of adults over age 60 in the United States use these supplements regularly to support heart health.
However, a new study reveals that regular use of fish oil supplements may increase the risk of first-time stroke and atrial fibrillation (AFib) among individuals with good cardiovascular health. AFib, a type of arrhythmia or irregular heartbeat, is often described as a flutter or pounding sensation in the chest.
Concerns from Medical Experts
“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. Freeman noted that over-the-counter fish oil is rarely recommended by professional medical societies and questioned its widespread use.
Findings from the Study
The study analyzed data from over 415,000 people aged 40 to 69 participating in the UK Biobank, a longitudinal health study in the United Kingdom. Nearly one-third of the participants, who were followed for an average of 12 years, reported regular use of fish oil supplements.
For individuals without pre-existing heart conditions, regular fish oil supplement use was associated with a 13% higher risk of developing atrial fibrillation and a 5% increased risk of stroke, according to the study published in BMJ Medicine.
Issues with Over-the-Counter Fish Oil
Freeman highlighted issues with over-the-counter fish oil, including lack of purity, consistency, and potential contamination with heavy metals such as mercury. He pointed out that studies over the past decade have shown mixed or negative results for over-the-counter fish oil, with some indicating potential harm, such as increased risk of stroke and AFib.
Interestingly, the study found that individuals with existing heart disease at the start 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 with regular use of fish oil.
Prescription Fish Oil and Caution
Prescription versions of fish oil, such as Vascepa and Lovaza, are used to manage high triglycerides and other cardiovascular risk factors. However, Freeman noted that even these highly purified versions carry a risk for AFib and sometimes stroke, making doctors cautious.
“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,” Freeman said.
Food Sources for Omega-3s
Dr. Richard Isaacson, an Alzheimer’s preventive neurologist, recommends testing for omega-3 fatty acid levels before taking supplements. He suggests obtaining omega-3s from food sources such as sardines and wild-caught salmon, which are high in healthy unsaturated fats and lower in mercury. Farm-raised salmon is not ideal due to water impurities.
Other good sources of omega-3s include lake trout, mackerel, herring, and albacore tuna, though tuna consumption should be limited to twice a week due to mercury levels. Non-fish sources like algae, seaweed, chia seeds, edamame, flaxseed, hempseeds, and walnuts are also rich in omega-3s, though plant-based omega-3s may be harder to metabolize for individuals with high levels of omega-6s, found primarily in vegetable oils.