Taking a daily dose of folic acid may be an effective way to lower the risk of heart disease and strokes, suggests new research published in the British Medical Journal.

The findings the results of previous studies.

The mechanism involved is folic acid's ability to lower homocysteine levels in the blood. Homocysteine is an amino acid, one of the building blocks of protein, produced in the human body.

Whether higher levels of homocysteine cause cardiovascular disease and stroke has long been a matter of scientific debate.

Dr. David Wald of the Wolfson Institute for Preventive Medicine in London and colleagues conducted an analysis of several studies in an effort to resolve the question.

The team analyzed studies of several types: those that investigated a potential link between homocysteine levels and heart attacks; several that involved participants with a genetic predisposition to higher homocysteine levels; and some that looked at the effects of reducing homocysteine levels.

Overall, the studies were consistent with the observation that lowering homocysteine levels does provide a protective benefit by as much as 10 percent to 20 percent.

Since folic acid reduces homocysteine concentrations in the blood, it is reasonable to conclude that increasing folic consumption will lower the risk of heart attacks and stroke, say the authors of the study.

Natural sources of folic acid include leafy green vegetables such as spinach, broccoli and Brussels sprouts, as well as asparagus, green beans, peas, fortified breakfast cereals, bread, lentils, dried beans and oranges.