Effects of B vitamins and omega 3 fatty acids on cardiovascular diseases: a randomised placebo controlled trial
What this study found
Daily B vitamin or omega-3 supplementation did not reduce major cardiovascular events in this secondary prevention population, so routine use for cardiovascular prevention was not supported. In the combined B vitamins plus omega-3 arm, major cardiovascular events were 75 vs 82 (hazard ratio 0.90, 95% CI 0.66 to 1.23; P=0.50), stroke was lower (21 vs 36; hazard ratio 0.57, 0.33 to 0.97; P=0.04), but all-cause mortality was higher (72 vs 45; hazard ratio 1.55, 1.07 to 2.25; P=0.02). Non-fatal myocardial infarction was not reduced (28 vs 32; hazard ratio 0.88, 0.53 to 1.46; P=0.61).
- Study & population
- Randomized placebo-controlled trial conducted in France among adults aged 45 to 80 years with prior ischemic cardiovascular disease, including myocardial infarction, acute coronary syndrome, or ischemic stroke within the previous year.
- Intervention
- Three oral active regimens were tested: B vitamins alone (5-methyltetrahydrofolate 560 μg, vitamin B-6 3 mg, and vitamin B-12 20 μg; two capsules daily), omega-3 fatty acids alone (600 mg total EPA and DHA in a 2:1 ratio; two capsules daily), or the combination of both regimens at the same doses.
- Key limitation
- The trial was limited to a French secondary-prevention population with prior ischemic events, which may reduce generalizability to other settings or to earlier post-event treatment.
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Open PDFOriginal abstract
Objective To investigate whether dietary supplementation with B vitamins or omega 3 fatty acids, or both, could prevent major cardiovascular events in patients with a history of ischaemic heart disease or stroke. Design Double blind, randomised, placebo controlled trial; factorial design. Setting Recruitment throughout France via a network of 417 cardiologists, neurologists, and other physicians. Participants 2501 patients with a history of myocardial infarction, unstable angina, or ischaemic stroke. Intervention Daily dietary supplement containing 5-methyltetrahydrofolate (560 μg), vitamin B-6 (3 mg), and vitamin B-12 (20 μg) or placebo; and containing omega 3 fatty acids (600 mg of eicosapentanoic acid and docosahexaenoic acid at a ratio of 2:1) or placebo. Median duration of supplementation was 4.7 years. Main outcome measures Major cardiovascular events, defined as a composite of non-fatal myocardial infarction, stroke, or death from cardiovascular disease. Results Allocation to B vitamins lowered plasma homocysteine concentrations by 19% compared with placebo, but had no significant effects on major vascular events (75 v 82 patients, hazard ratio, 0.90 (95% confidence interval 0.66 to 1.23, P=0.50)). Allocation to omega 3 fatty acids increased plasma concentrations of omega 3 fatty acids by 37% compared with placebo, but also had no significant effect on major vascular events (81 v 76 patients, hazard ratio 1.08 (0.79 to 1.47, P=0.64)). Conclusion This study does not support the routine use of dietary supplements containing B vitamins or omega 3 fatty acids for prevention of cardiovascular disease in people with a history of ischaemic heart disease or ischaemic stroke, at least when supplementation is introduced after the acute phase of the initial event. Trial registration Current Controlled Trials ISRCTN41926726.