Omega-3 FA supplements do not prevent heart disease in latest study
Taking marine-derived omega-3 fatty acid (FA) supplements does not appear to protect participants from coronary heart disease (CHD) and major vascular events, regardless of history of vascular disease, lipid levels, statin use, or diabetes, suggests a recent meta-analysis.
“It provides no support for current recommendations for the use of such supplements in people with a history of CHD,” said the researchers.
The meta-analysis included 10 randomized trials involving 77,917 high-risk individuals (mean age 64 years, 61.4 percent male) and a treatment duration of ≥1 year (mean 4.4 years). Eight trials were double-blinded, comparing omega-3 FA (EPA* dose range, 226–1,800 mg/day) supplements vs placebo, while two were of an open-label design without placebo control. [JAMA Cardiol 2018;3:225-234]
Compared with placebo (or open-label control), omega-3 FA supplementation was not significantly associated with a reduced risk of any CHD events (rate ratio [RR], 0.96; p=0.12), including CHD death (RR, 0.93; p=0.05) or nonfatal myocardial infarction (MI; RR, 0.97; p=0.40).
Neither were omega-3 FAs significantly associated with reductions in the rates of major vascular events (RR, 0.97; p=0.10), including revascularizations (RR, 0.99; p=0.61) or stroke (RR, 1.03; p=0.56). The findings remained in prespecified subgroup analyses defined by sex, prior CHD, diabetes, lipid levels, or statin use.
The overall results also did not change after excluding the JELIS trial, which tested EPA alone instead of EPA and DHA combined. [Lancet 2007;369:1090-1098]
In addition, omega-3 FA supplementation was not significantly associated with altered risk of all-cause mortality (RR, 0.96; p=0.16).
“The conclusions of the present meta-analysis are consistent with those of a 2016 report for the US Agency for Healthcare Research and Quality that also involved study-level data from the same 10 large trials,” the researchers noted.
While the AHA** guideline states that taking omega-3 FA supplements for CHD prevention “is probably justified” in people with a history of CHD, the 2016 guidelines from ESC*** and EAS# indicated that whether omega-3 FAs have a protective effect remains debatable. [Circulation 2017;135:e867-e884; Eur Heart J 2016;37:2315-2381]
“The results of the present meta-analysis provide no support for the recommendations to use approximately 1 g/day of omega-3 FAs in individuals with a history of CHD for the prevention of fatal CHD, nonfatal MI, or any other vascular events,” said the researchers.
Nevertheless, the researchers acknowledged that the 95 percent confidence intervals used in the meta-analysis “cannot exclude a 7 percent lower risk of major vascular events and a 10 percent lower risk of CHD associated with omega-3 FA supplements.” They also added that currently ongoing large trials, such as ASCEND## and VITAL###, will provide further evidence if omega-3 FAs may affect risk of major vascular events.
As the meta-analysis looked at the effects of fish oil supplements only, it remains important that people still meet guidelines for dietary fish consumption of at least two intakes per week, according to study principal investigator Dr Robert Clarke from the University of Oxford, UK.