Folic acid could dramatically reduce the risk of heart disease, deep vein thrombosis and stroke if levels of homocysteine (an amino acid) were reduced, according to researchers in this week's British Medical Journal.
The conclusion rests on strong evidence that a raised homocysteine concentration is a cause of cardiovascular disease. Homocysteine can be lowered by folic acid. Researchers at the University of Ulster reported earlier this year that folic acid and three other related B-vitamins can prevent the accumulation of a high blood level of homocysteine.
The researchers analysed more than 100 studies on the association between serum homocysteine and cardiovascular disease. Some looked at the prevalence of a genetic mutation, which increases homocysteine (genetic studies), and some looked at homocysteine and disease risk (prospective studies).
The genetic studies and the prospective studies did not share the same potential sources of error but both yielded similar results - strong evidence that the association between homocysteine and cardiovascular disease is causal. On this basis, the researchers estimate that folic acid could reduce the risk of ischaemic heart disease by 16 per cent, deep vein thrombosis by 25 per cent and stroke by 24 per cent.
The researchers suggest that folic acid could be taken as tablets by people at high risk (those with existing cardiovascular disease or anyone above age 55), or possibly supplied to the general public through food fortification or a combination of both, as a simple and safe means of prevention.
Folic acid food fortification has already been introduced in the US, Canada and Chile to prevent the birth defect spina bifida. However Europe has adopted a much more cautionary approach. In the UK, the Food Standards Agency recently decided not to recommend the fortification of grain on the grounds that not enough was known about the potential adverse effects.
However, many medical experts see fortification as an effective and inexpensive way to preventing neural tube defects in infants and see concerns about the safety of food fortification for people at risk of vitamin B 12 deficiency as overexaggerated.
Folic acid can be found in green leafy vegetables, fruit, nuts and pulses.