Adding folic acid to food is the most successful way of reducing neural tube defects, a new report suggests.
The policy, used in America and Canada, has resulted in the number of neural tube defects falling by more than three quarters since folic acid fortification was introduced there in 1996.
The study, published in the British Medial Journal, also concluded that Government recommendations advising women to increase their intake of folic acid failed to reduce these birth defects in nine European countries and Israel.
Researchers looked at the incidence rates of neural tube defects in England and Wales, Finland, the Netherlands, Ireland, Hungary, Portugal, three regions in France, two regions of Italy and Israel.
They examined the incidence rates of neural tube defects before and after government's recommendations about taking folic acid supplements, in a study of 13 million births.
The researchers believe that government recommendations did not work because the majority of women either took no notice of them, or only did so for a short while after the publicity campaign.
By fortifying food - such as flour - with folic acid ensures that women get the necessary intake without having to think about it, the team concluded.
In 2000 the Committee on Medical Aspects of Food and Nutrition Policy recommended that the fortification of flour should be introduced in Britain. But the Department of Health consulted the Food Standards Agency to consider the issue.
Two years later the agency asked for more research to be carried out because of potential risks to the elderly. But Canadian research, published last September, detected no ill effects on the elderly, whose vitamin B12 deficiency can be masked by folic acid.
ASBAH's Executive Director Andrew Russell told Link that Britain now lags behind 30 to 40 countries that have added folic acid to food.
He said: “Around 100 babies are born every year with spina bifida, and many more are terminated early because the condition has been detected. That is not a good strategy when you can do primary prevention by adding folic acid to food.”