Healthy adults who take fish oil supplements may be at higher risk of heart problems for the first time, a study suggests.
As a rich source of omega-3 fatty acids, fish oil is often recommended as a dietary preventative to prevent the development of cardiovascular diseases. Other beneficial effects are also attributed to it, such as relieving joint pain.
But new research suggests that taking the popular supplement could actually increase the chances of heart disease and stroke in healthy adults, while reducing the risk in those with a history of the disease.
The study, which involved more than 415,000 Britons, looked at associations between fish oil supplements and new cases of atrial fibrillation, heart attack, stroke and heart failure and death.
They evaluated the potential of these supplements on the risk of progressing from classified good heart health to the secondary stage of atrial fibrillation, the third stage of major cardiovascular events such as heart attack and death.
Healthy adults who take fish oil supplements could be at higher risk of heart problems for the first time, study suggests (Stock Photo)
The study, which involved more than 415,000 Britons, looked at associations between fish oil supplements and new cases of atrial fibrillation, heart attack, stroke and heart failure and death (File photo).
Nearly a third (130,365) of participants, ages 40 to 69, said they regularly used fish oil supplements, including a large number of older, white people and women.
Alcohol intake and the proportion of fatty and non-fatty fish consumed were also higher, while the proportions of current smokers and those living in deprived areas were lower.
During an average follow-up of 12 years, 18,367 developed atrial fibrillation, an abnormal heart rhythm disorder, 22,636 had a heart attack or stroke or developed heart failure, and 22,140 died (14,902 without atrial fibrillation or heart disease).
Of those who went from good heart health to atrial fibrillation, 3,085 developed heart failure, 1,180 had a stroke and 1,415 had a heart attack.
About 2,436 of the people with heart failure died, along with 2,088 who suffered a stroke and 2,098 after a heart attack, according to findings published in BMJ Medicine.
The findings indicated that regular use of fish oil supplements had different roles in cardiovascular health, disease progression and death.
Those who used them regularly without signs of illness had a 13 percent higher risk of developing atrial fibrillation and a five percent higher risk of having a stroke.
But among those who had cardiovascular disease to begin with, regular use of fish oil supplements reduced the risk of progressing from atrial fibrillation to heart attack by 15 percent and from heart failure to death by nine percent.
The risk of going from good health to heart attack, stroke or heart failure was six percent higher in women. It was also six percent higher among non-smokers among fish oil consumers.
Meanwhile, the protective effect of these supplements on the transition from good health to death was greatest in men (seven percent lower risk) and older participants (11 percent lower risk).
Alcohol intake and the proportion of fatty and non-fatty fish consumed were also higher, while the proportions of current smokers and those living in deprived areas were lower (Stock photo)
Led by Sun Yat-Sen University, China, the researchers admit limitations to the study, including the fact that the dosage and formulation of the fish oil were not recorded, which experts say could be key to the results.
However, they conclude: “Regular use of fish oil supplements could play different roles in the progression of cardiovascular disease.”
“Further studies are needed to determine the precise mechanisms for the development and prognosis of cardiovascular diseases with regular use of fish oil supplements.” It is not the first study to reach such conclusions with a 2018 Cochrane review of research that compared 79 trials and found there was “little or no difference in the risk of cardiovascular events, coronary deaths, coronary heart disease events, stroke or cardiac irregularities.