Regular use of fish oil supplements linked to increased risk of heart disease in healthy people

Regular use of fish oil supplements may increase, rather than decrease, the risk of developing heart disease and stroke for the first time among those in good cardiovascular health, but may slow the progression of existing poor cardiovascular health and reduce the risk of death, study results suggest. large long-term study, published in the open access journal BMJ Medicine.

Fish oil is a rich source of omega-3 fatty acids and as such is recommended as a dietary preventative to prevent the development of cardiovascular diseases. But the evidence on how much protection it offers is inconclusive, the researchers explain.

To strengthen the evidence base, we set out to estimate the associations between fish oil supplements and new cases of atrial fibrillation; heart attack, stroke and heart failure; and death from any cause in those without known cardiovascular disease.

And they evaluated the potential role of these supplements in the risk of progressing from good heart health (primary stage), to atrial fibrillation (secondary stage), to major cardiovascular events, such as heart attack (tertiary stage) and death (stage final). scenery).

They were based on 415,737 UK Biobank study participants (55% women), aged 40 to 69, who were surveyed between 2006 and 2010 to collect basic information. This included their usual dietary intake of oily and non-oily fish and fish oil supplements.

Participants’ health was tracked until the end of March 2021 or until death, whichever came first, using data from medical records.

Nearly a third (130,365; 31.5%) of participants said they used fish oil supplements regularly. This group included higher proportions of older people, 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.

Over an average follow-up period of nearly 12 years, 18,367 participants developed atrial fibrillation, 22,636 had a heart attack or stroke or developed heart failure, and 22,140 died; 14,902 without atrial fibrillation or serious cardiovascular disease.

Among those who went from good cardiovascular health to atrial fibrillation, 3,085 developed heart failure, 1,180 had a stroke and 1,415 had a heart attack. And 2,436 of those with heart failure died, as did 2,088 of those who had suffered a stroke and 2,098 of those who had suffered a heart attack.

The findings indicated that regular use of fish oil supplements had different roles in cardiovascular health, disease progression and death.

For those without known cardiovascular disease at the start of the follow-up period, regular use of fish oil supplements was associated with a 13% increased risk of developing atrial fibrillation and a 5% increased risk of having a stroke.

But among those who had cardiovascular disease at the start of the follow-up period, regular use of fish oil supplements was associated with a 15% lower risk of progressing from atrial fibrillation to a heart attack, and a 9% lower risk of progressing from atrial fibrillation to heart attack. heart failure. to dead.

Further analysis revealed that age, sex, smoking, consumption of non-fatty fish, high blood pressure, and use of statins and blood pressure-lowering medications changed the observed associations.

Regular use of fish oil supplements and the risk of going from good health to heart attack, stroke or heart failure was 6% higher in women and 6% higher in non-smokers. And the protective effect of these supplements on the transition from good health to death was greatest in men (7% lower risk) and in older participants (11% lower risk).

As this is an observational study, no conclusions can be drawn about causal factors, the researchers acknowledge. And no potentially influential information was available on the dosage or formulation of fish oil supplements. And since most of the participants were white, the findings might not be applicable to people of other ethnicities, they add.

But they conclude: “Regular use of fish oil supplements could have different roles in the progression of cardiovascular disease. More studies are needed to determine the precise mechanisms for the development and prognosis of cardiovascular disease events with regular use of fish oil supplements. fish oil supplements.


Magazine reference:

Chen, G., et al. (2024). Regular use of fish oil supplements and the evolution of cardiovascular diseases: a prospective cohort study. BMJ Medicine.