A research team at the University of Ulster in Coleraine has confirmed that yet another common vitamin can help protect against heart disease.
This brings to four the number of vitamins found to help block a hormone that can cause long-term damage to blood vessels.
New research by the group into the role of the B vitamin, riboflavin, is published in the American Journal of Clinical Nutrition.
The team found that riboflavin can help reduce levels of the damaging hormone, homocysteine, particularly in people with a genetic tendency to have high homocysteine levels.
Most people are aware that high cholesterol levels can be a contributor to heart disease, but few have heard of homocystine.
Research at Coleraine and other centres has shown, however, that high homocystine levels are at least as dangerous in terms of heart disease as high cholesterol.
Riboflavin now joins folic acid (folate), vitamin B12 and vitamin B6 as nutrients that can help reduce homocystine levels.
Folic acid is also essential in reducing the risk of spina bifida and other birth defects in babies.
About 12 per cent of the general population have a genetic make-up that predisposes them to high homocystine levels.
The new Coleraine study looked in particular at this group and found that riboflavin prevented homocysteine build-up for these individuals.
"The evidence appears to suggest that if riboflavin intake is good the genetic predisposition towards elevated homocysteine may be overcome," said the lead author in the research, Prof Helene McNulty, professor of human nutrition and dietetics at the School of Biomedical Sciences at Coleraine. Riboflavin is found in dairy foods such as milk and yoghurt.
Controlling cholesterol levels could be difficult, but it was comparatively simple to limit homocysteine through the intake of folate and the B vitamins, the findings suggest. "To protect against elevated homocysteine in all individuals, including those with the genetic predisposition, a good intake of all four B-vitamins is recommended," Prof McNulty said.
Researchers are now looking into whether vitamins may also have a role in preventing other diseases including bowel and breast cancer.
Research into nutrients in foods became a hot topic in 1991 when it was discovered that folic acid given to mothers before conception and in early pregnancy could prevent spina bifida and other birth defects.
Intensive work on the subject was done at Trinity College Dublin and Coleraine, as well as centres around the world.
Prof McNulty has continued to study how nutrients influence the progression of disease, particularly the influence of vitamins on homocysteine levels.
The hormone affects blood vessels in particular, and over time high levels can cause the damage typical of heart disease while also increasing the risk of stroke.
Folic acid and vitamins B12 and B6 all help suppress homocysteine levels and so may be protective against vascular disease and stroke.
They are less helpful in the 12 per cent of patients who have a particular genetic predisposition however, hence the importance of Prof McNulty's findings relating to riboflavin.
"The evidence appears to suggest that the effect on homocysteine of this genotype [genetic makeup] is ultimately under the influence of riboflavin," she said.