Published in the September issue of the Lancet Neurology, the study found no protective benefits in just over three years of follow-up.
Previous studies have indicated a link between raised levels of homocysteine – an amino acid in the blood – and an increased risk of heart disease or stroke. B vitamins are thought to help reduce homocysteine levels, prompting suggestions that the vitamins could help reduce the risk of cardiovascular disease (CVD).
However, the authors of the current study highlight that the heart benefits of B vitamins for people who have already had a stroke are still unknown. Their study, which they say is the first placebo-controlled trial of B vitamins in stroke patients, aimed to assess whether daily supplementation with vitamin B taken in combination with medical care could deliver any protective benefits in this population group.
Dubbed VITATOPS (VITAmins TO Prevent Stroke), the trial involved 8164 people who had suffered from a stroke within the last seven months. Patients were enrolled from 123 medical centers across 20 countries and were randomly assigned to receive B vitamins (4089) or placebo (4075) in addition to their standard drug therapy.
The B vitamins, administered once daily, included 2mg folic acid, 25 mg vitamin B6, and 0.5mg vitamin B12.
Patients were then followed up for an average of 3.4 years, although 9 percent of participants were lost to follow-up.
The researchers found that the average total homocysteine level was 3.8µmol/L lower in the vitamin group than in the placebo group.
However, this did not appear to have any significant impact on lowering the incidence of vascular events, including stroke, heart attack or vascular death. In total, 616 patients taking B vitamins (15 percent) experienced a “major vascular event”, compared with 678 patients (17 percent) in the placebo group.
The researchers concluded that their results “do not support the use of B vitamins to prevent recurrent stroke” but noted that a planned meta-analysis of individual data from all previous, and three ongoing, randomised controlled trials of B vitamins will provide “more reliable estimates of thelong-term effects of B vitamins in the prevention of strokeand other major vascular events” among stroke patients.
The potential role of B vitamins in heart health is controversial in that many of the randomised controlled trials have focused on people already suffering from heart disease.
As a result, some of these studies have been criticized for not answering the question of whether long-term B vitamin supplementation combined with other healthy lifestyle habits could have helped prevent cardiovascular disease before it occurred.
Commenting on the current study, Andrew Shao, senior VP of scientific and regulatory affairs at the supplement trade group Council for Responsible Nutrition (CRN) said that the study was well-designed but that its duration may not have been sufficient for a benefit to manifest. He also noted the limitation related to the incomplete follow-up.
He added that “the trial tested the hypothesis of secondary prevention, essentially treating B vitamins like drugs. The results of this study in no way address the question of whether taking B vitamins can have a beneficial effect on primary prevention”.
“The author highlights the need for continued research in this area, something we would agree with, and also reiterates that subtle benefits can have strong impacts on a population basis, and specifically notes his conclusions are in reference to secondary (not primary) prevention. It’s important for researchers to include these kinds of qualifiers, and we appreciate that the author has done so,” Shao told NutraIngredients-USA.com.
B vitamins in patients with recent transient ischaemic attack or stroke in the VITAmins TO Prevent Stroke (VITATOPS) trial: a randomised, double-blind, parallel, placebo-controlled trial