LONDON - Can taking folic acid supplements reduce the risk of heart disease and stroke? British researchers believe it can.

After analysing evidence from earlier studies, a team of scientists in Britain said on Friday there is enough research that shows folic acid lowers levels of the amino acid homocysteine and reduces the odds of cardiovacular disease.

"The evidence is very persuasive that lowering homocysteine with folic acid will lower your risk of heart attack and stroke by about 10-20 percent," David Wald, of the Wolfson Institute for Preventive Medicine, Barts and the London, Queen Mary School of Medicine and Dentistry in London, said in an interview.

Folic acid is a synthetic compound of folate, a B vitamin found in green leafy vegetables and liver. Women are advised to take folic acid before conceiving and during the early months of pregnancy to prevent neural tube disorders such as spina bifida.

Homocysteine is thought to increase the risk of cardiovascular disease by damaging the inner lining of arteries.

Wald and his team analysed results of large cohort trials looking at homosysteine and heart attacks and strokes in mainly healthy people and others that tested the effects of lowering levels of the amino acid.

They also examined studies of people with a genetic mutation, which occurs in one in 10 people, that increases their homocysteine level and the impact of folic acid in reducing it.

"The evidence shows clearly that those people who have the genetic defect who have higher homocysteine levels have a high risk," said Wald. "The work we have done looks closely at this type of evidence because if you take enough folic acid, or folate, you can cancel out the effect of this mutation".

The cohort and genetic studies showed a protective effect from lower homocysteine levels. Wald said there are trials that have shown no effect but he explained that they were too small, too short-term or too inconclusive.

"All the evidence put together is compelling," he said, adding that folic acid is a cheap and simple way to reduce heart disease and strokes.

Cardiovascular disease is a leading cause of death worldwide. A family history of the disease, smoking, high blood pressure, raised cholesterol, obesity, lack of exercise and diabetes are risk factors for cardiovascular disease.