This is a surprise.
Supplements are often used to support various aspects of health, from improving sleep to enhancing memory, but they can sometimes cause unexpected side effects. This is true even for widely used supplements like fish oil. Recently, some medical experts have raised concerns after a study suggested that taking fish oil might actually increase the risk of certain heart conditions.
The study, published in the journal BMJ Medicine, examined health data from over 415,000 people in the UK, aged 40 to 69, tracked over an average period of 12 years. Researchers aimed to determine whether those who reported taking fish oil supplements regularly experienced different outcomes related to cardiovascular diseases such as atrial fibrillation, heart failure, and heart attacks. They compared individuals with no prior heart disease to those already diagnosed.
The findings revealed that healthy individuals who regularly consumed fish oil were 13% more likely to develop atrial fibrillation—an irregular heartbeat that can trigger serious heart complications—compared to those who did not take fish oil. This group was also found to have a 5% higher risk of stroke, according to the British Heart Foundation. However, for patients already living with heart disease, the results were more favorable. Those with atrial fibrillation who took fish oil supplements had a 15% lower risk of heart attacks, and individuals with heart failure experienced a 9% decrease in mortality risk compared to non-users.
These results align with some earlier studies. For example, a 2020 meta-analysis in Pharmacological Research showed that omega-3 supplementation reduced mortality in heart disease patients. However, other research has contradicted these findings. A 2020 study in Circulation Research found no increased risk of atrial fibrillation among fish oil users. Conversely, a 2021 meta-analysis published in Circulation reported that omega-3 intake could raise the likelihood of atrial fibrillation, echoing concerns similar to the recent study.
The researchers pointed out several limitations, noting that the studies were observational rather than clinical trials, which limits the ability to establish cause and effect. Additionally, definitions of “regular” fish oil use were vague, and there was no information on whether participants consistently took supplements throughout the study period.
Given the mixed evidence, health experts advise caution and emphasize that supplements should not replace a balanced diet. Tracy Parker, a senior dietitian at the British Heart Foundation, highlighted the benefits of the Mediterranean diet, which includes fish, plenty of fruits, vegetables, legumes, nuts, and whole grains, as a proven strategy for reducing heart disease risk. Until further research clarifies the risks and benefits, adopting such dietary habits remains the recommended approach to maintaining cardiovascular health.
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