Vitamin B supplements may not cut down the chances of a person getting a second cardiovascular incident like stroke or heart attack, says a new study conducted by researchers in Australia.

Doctors currently prescribe supplements containing the B-group vitamins to patients with a history of cardiovascular diseases in an attempt to cut down homocysteine levels that are implicated in stroke or heart attacks.

The B-group vitamins do help in reducing homocystein in the blood to a certain level, but are not of much help in preventing a second stroke or heart attack, say researchers at Royal Perth Hospital in Western Australia.

In a study titled Vitamins to Prevent Stroke (VITATOPS), the researchers tested a combination of folic acid, vitamin B6 and vitamin B12 in 8,164 patients who had a recent stroke or transient ischemic attack. The patients were given B-group vitamins or a placebo daily in addition to their regular medicines for three years.

When the study group analyzed the trial data after 3.4 years of follow-up, the researchers found the B-group vitamins were no more effective than placebo. As many as 15 percent of the people taking these vitamins had a second stroke or heart attack, compared with 17 percent of those receiving placebo.

However, there was significant reduction in homocystein levels among patients who took B-group vitamins. Moreover, people taking the vitamins had no adverse reactions and the body tolerated these supplements properly.

"The B-group vitamins are safe, but they were not, significantly more effective than placebo in preventing major vascular events among stroke and TIA [transient ischemic attack] patients," says lead researcher Dr. Graeme J. Hankey, head of the stroke unit at Royal Perth Hospital in Western Australia.

The B-group vitamins have not been proven to have a role in secondary stroke prevention. The research group said. However, Dr. Hankey, does not think the new findings are the end of the road for B vitamins in stroke prevention.

“We need to see the effect of B-group vitamins in the three other ongoing trials, particularly in patients who have been treated for several years, and particularly in patients with stroke caused by small vessel intracranial disease," he says in the study report published in the medical journal Lancet Neurology.