A review of the literature, which was limited to eight randomised controlled trials equivalent to 24,210 participants found no difference between the B vitamins and placebo for heart attack, stroke, or reductions in the risk of total mortality in people already suffering from heart disease.
The potential role of B vitamins in heart health, by reducing levels of the amino acid homocysteine reported to increase the risk of cardiovascular disease, is controversial. The controversy is set to continue, with the new review being including only five trials with homocysteine data, and all the participants at risk of, or already suffering from, cardiovascular disease.
Various groups have already spoken out about the review, indicating that the review does not reach a “balanced conclusion”.
Epidemiological studies have linked increased blood levels of the amino acid homocysteine to an increased risk of cardiovascular disease (CVD). It has been suggested that by lowering the levels of homocysteine in the blood with B-vitamins, people could cut the risk of CVD.
The new review found “no evidence that homocysteine-lowering interventions, in the form of supplements of vitamins B6, B9 or B12 given alone or in combination, at any dosage compared with placebo or standard care, prevents myocardial infarction, stroke, or reduces total mortality in participants at risk or with established cardiovascular disease”.
B for benefits
A study from the American Journal of Cardiology, however, recently reported that folate supplements could reduce all-cause mortality in people with coronary artery disease (CAD).
Researchers from the Rabin Medical Center in Petah Tikva and Tel Aviv University report that supplements of folic acid (at least 400 micrograms per day) with or without additional B vitamins was administered for an average period of 115 months.
The Israeli researchers report that folate was associated with 28 per cent lower all-cause mortality in people with high homocysteine levels (greater than 15 micromoles per litre), but not in people with lower homocysteine levels.
“Long-term folate-based vitamin therapy was independently associated with lower all-cause mortality in patients with CAD and elevated homocysteine levels,” report the researchers, led by Aviv Mager. “This association was not observed in patients with lower homocysteine levels.”
For reaction to the Cochrane Systematic Review, please click here.
1. Cochrane Database of Systematic Reviews
2009, Issue 4. Art. No.: CD006612, Publication Date: 7 October 2009
“Benefit of B Vitamins for reducing cardiovascular events”
Authors: A.J. Marti-Carvajal, I. Sola, D. Lathyris, G. Salanti
2. American Journal of Cardiology
Volume 104, Issue 6, Pages 745-749
“Impact of Homocysteine-Lowering Vitamin Therapy on Long-Term Outcome of Patients With Coronary Artery Disease”
Authors: A. Mager, K. Orvin, N. Koren-Morag, I.E. Lev, A. Assali, R. Kornowski, M. Shohat, A. Battler, D. Hasdai