MedWire News: Women who regularly take vitamin B supplements do not have a lower risk of heart attacks, strokes and other cardiovascular 'events' than other women, US research shows.

"Homocysteine [an amino acid produced by the body] levels have been directly associated with cardiovascular risk in observational studies; and daily supplementation with folic acid, vitamin B6, vitamin B12 or a combination have been shown to reduce homocysteine levels to varying degrees," explain Dr Christine Albert, from Brigham and Women's Hospital in Boston, Massachusetts, and colleagues.

To investigate whether the regular use of vitamin B supplements can reduce the risk of cardiovascular events, the researchers studied 5442 women, aged 42 years and older, who had either a history of cardiovascular disease or at least three cardiovascular risk factors, such as high blood pressure, high cholesterol and diabetes.

The participants were assigned to take a daily supplement containing folic acid, vitamin B6 and vitamin B12 or a dummy pill and were monitored for around 7 years.

In total, 796 of the women suffered a cardiovascular event during the study period, with some individuals experiencing more than one event.

Analysis showed that, overall, women taking the vitamin supplement were just as likely to suffer a cardiovascular event over the course of the study as those taking the dummy pill. Indeed, 14% of participants in both groups experienced such an event.

Furthermore, when analysed separately, the risk of heart attack, stroke or death due to cardiovascular disease were similar among the two groups.

However, the team did find that average homocysteine levels were 19% lower in women taking the vitamin supplement than in those taking the dummy pill.

"After 7.3 years of treatment and follow-up, a combination pill of folic acid, vitamin B6 and vitamin B12 did not reduce a combined end point of total cardiovascular events among high-risk women, despite significant homocysteine lowering," the researchers summarise in the Journal of the American Medical Association.

They conclude: "Our results are consistent with prior randomised trials performed primarily among men... and do not support the use of folic acid and B vitamin supplements as preventive interventions for cardiovascular disease."