ملتقى طلاب وطالبات جامعة الملك فيصل,جامعة الدمام - Vitamin B supplementation not linked with stroke prevention

B vitamins appear to be no more effective than placebo in preventing strokes or heart attacks, a Lancet Neurology study published online (4 August 2010) reveals.
Daily doses of B vitamins were found to be safe but did not reduce the incidence of major vascular events in those with a history of stroke or transient ischaemic attack (TIA).
It has been shown that vitamin B lowers homocysteine levels — raised levels are a risk factor for major vascular events.
The present study assessed whether a once daily supplement of vitamin B6, vitamin B12 and folic acid would reduce the combined incidence of non-fatal stroke, non-fatal myocardial infarction (MI) or death in people who had had recent stroke or TIA of the brain or eye.
Over 10 years 8,164 patients were randomly assigned to receive B vitamins or placebo. In total, 616 patients (15 per cent) taking B vitamins and 678 (17 per cent) taking placebo had a stroke, suffered an MI or died (risk ratio 0.91, 95 per cent confidence interval 0.82–1; P=0.05). The authors conclude that their results do not support the use of B vitamins to prevent recurrent stroke.
Helen Williams, a consultant pharmacist for cardiovascular disease, said the results confirm those of previous studies: “Numerous studies have sought to demonstrate the benefit of vitamin supplementation on cardiovascular risk, focusing primarily on patients with coronary heart disease. This study confirms the findings of these previous studies, that vitamin B supplementation to lower homocysteine levels, while safe, does not result in a reduction in cardiovascular events.”
She suggested: “Patients should be advised that there is no evidence to support the use of vitamins B, C and E or folic acid to reduce cardiovascular risk and are no substitute for the interventions that we know do reduce the risk of future events, particularly aspirin, control of blood pressure and statin therapy.”

Study method and results

Patients from 20 countries who had a stroke or TIA within the past seven months were assigned to a daily tablet of B vitamins (2mg folic acid, 25mg vitamin B6, and 0.5mg vitamin B12) or a placebo tablet.
Compared with placebo, treatment with B vitamins was not associated with a significant reduction in the risk ratio for stroke (P=0.25), myocardial infarction (P=0.86) or death from any cause (P=0.49).
There were no differences in adverse effects
between the two groups