B vitamin and omega 3 fatty acid supplements do not reduce secondary CV event risk
MedWire News: Research suggests that supplementation with B vitamins or omega 3 fatty acids does not prevent major cardiovascular (CV) events in patients with a history of ischemic heart disease or stroke.
The findings do not support the routine use of such dietary supplements for the prevention of CV disease, at least when supplementation is introduced after the acute phase of the initial CV event, says the research team.
Between 2003 and 2007, Pilar Galan (Université Paris, France) and colleagues randomly assigned 2501 patients (aged 45-80 years) with a history of myocardial infarction, unstable angina, or ischemic stroke to receive B vitamins alone, omega 3 fatty acids alone, both treatments, or placebo for a median duration of 4.7 years. The median time between the acute event and randomization in the trial was 101 days, the team notes.
B vitamin status and fatty acid profiles were measured at baseline, 1 year, and at the end of treatment; and major CV events, defined as a composite of nonfatal myocardial infarction, stroke, or death from CV disease, were recorded every 6 months after enrolment.
Galan's team found that allocation to B vitamins (5-methyltetrahydrofolate, vitamin B-6, and vitamin B-12) was associated with a 19% lower median plasma total homocysteine concentration, and that supplementation with omega 3 fatty acids increased plasma concentrations of fatty acids by 37%, compared with placebo.
As reported in the BMJ, 157 patients experienced a major confirmed CV event, with 20 individuals experiencing more than one.
However, treatment with omega 3 fatty acids or B vitamins had no significant effect on the risk for these events (81 vs 76 and 75 vs 82 patients, respectively, compared with placebo), and the cumulative incidence of major CV events was not affected by either treatment.
Treatment with B vitamins was associated with fewer stroke events (46% reduction), but had no significant effect on the rates of other CV events and mortality from all causes.
Omega 3 supplementation was not associated with any of the secondary outcomes.
However, the team does not rule out the possible positive effect of omega 3 supplementation if given at the acute phase.
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By Nikki Withers