Omega-3 supplements may guard against cardiac death
Taking long-chain omega-3 fatty acid (LC-OM3) supplements, mainly EPA* and DHA** omega-3s, was associated with a modest but significant reduction in cardiac death risk, according to a meta-analysis of randomized controlled trials (RCTs).
“One notable feature of EPA and DHA omega-3 supplementation is the low risk associated with its use. Because of the low risk for adverse effects, even a modest benefit is clinically meaningful,” said lead author Dr Kevin Maki of Midwest Biomedical Research at Center for Metabolic and Cardiovascular Health in Glen Ellyn, Illinois, US.
The meta-analysis included 14 RCTs involving 71,899 participants who underwent interventions for at least 6 months, with LC-OM3 comprising mainly EPA and/or DHA given as a dietary supplement or pharmaceutical concentrate. Participants were followed for incidence of cardiac death, which included ≥1 of the following outcomes: sudden cardiac death, fatal myocardial infarction, ischaemic heart disease death, coronary death, or cardiac death. [J Clin Lipidol 2017;doi:10.1016/j.jacl.2017.07.010]
In the primary analysis, a total of 1,613 cardiac deaths were reported in the LC-OM3 arms compared with 1,746 cases in the control groups (4.48 percent vs 4.87 percent). In a pooled relative risk analysis, individuals taking LC-OM3 supplements had an 8 percent lower risk of cardiac death than control subjects (p=0.015).
Subgroup analyses revealed that the reduction in cardiac death risk with LC-OM3 supplements was even greater (17 percent; p=0.005) in participants with elevated levels of triglycerides (≥150 mg/dL) or LDL cholesterol (≥130 mg/dL).
The greatest benefit of LC-OM3 supplements was seen in subgroup with >1 g/d of EPA + DHA, with a 30 percent reduction in cardiac death risk compared with controls (p=0.043). Other subgroups analysed including subjects who took LC-OM3 supplements for secondary prevention (p<0.001) or studies with <40 percent statin users at baseline (p=0.001) also showed a risk reduction with LC-OM3 ─ by 13 percent.
“The results … suggest that higher risk groups may be more likely to experience reductions in risk for cardiac death with LC-OM3 supplementation, particularly when provided at a higher dosage,” observed the researchers.
Findings from the meta-analyses of RCTs support results from previous observational cohort studies, which have suggested that higher LC-OM3 consumption was associated with lower risks of cardiac death.
“It’s important to note that these results align with the conclusions in the recent Science Advisory from the American Heart Association, which states that EPA and DHA omega-3 treatment ‘is reasonable’ for secondary prevention of coronary heart disease and sudden cardiac death,” said Maki.
Although several studies included in the meta-analysis were small or not optimally designed, such as control not using placebo, the researchers said these limitations were less likely to affect the outcome of cardiac death than other nonfatal events.