Research at the University of Ulster has shown that folic acid and three other related B-vitamins can prevent the accumulation of a high blood level of homocysteine, a new risk factor for heart disease and strokes.
The risk of high homocysteine is similar to the risk of high cholesterol - but the good news is that it is much easier to lower homocysteine levels through increased intake of folic acid.
As well as folic acid, vitamin B-12 and vitamin B-6 can help to prevent a build up of homocysteine.
Professor Helene McNulty, Professor of Human Nutrition and Dietetics at the School of Biomedical Sciences at the University of Ulster, said: "As the folic acid story unfolds, it is becoming clear that its importance goes beyond its major role for mothers-to-be and that, in fact, it is not just a woman's nutrient.
"New and emerging roles for this important vitamin include its probable role in protecting against heart disease and strokes by preventing the accumulation of homocysteine."
Professor McNulty's research confirmed that a fourth B-vitamin – riboflavin – can also play an important role in protecting against heart disease and strokes.
Around 12% of people have a particular genetic make-up which predisposes them to high homocysteine levels. Riboflavin, which is found in dairy foods like milk and yoghurt, prevents the build up of homocysteine in people with this genetic make-up.
Professor McNulty said: "The evidence appears to suggest that if riboflavin intake is good the genetic predisposition towards elevated homocysteine may be overcome. This is a classic example of what scientists call a gene-nutrient interaction".
"To protect against elevated homocysteine in all individuals, including those with the genetic predisposition, a good intake of all four B-vitamins is recommended."
This research was carried out with funding from the Northern Ireland Chest, Heart and Stroke Association and the EU.