Flour can be fortified with folic acid
Mandatory fortification of bread with folic acid would slash the risk of babies being born with a heart problem, experience from Canada shows.
Rates of severe congenital heart defects among newborns in Quebec fell significantly after the move to fortify flour and pasta began in 1998.
The British Medical Journal online study lends support to calls for introducing fortification to Europe.
But others argue against this, saying it would inevitably harm some people.
The fear is that adding folic acid to products like bread could harm some elderly people if they are deficient in other B vitamins.
In extreme cases, this can cause irreversible damage to the nervous system.
There is also concern that it may also increase the risk of certain cancers, including bowel cancer, in some people.
In 2007 the UK's watchdog, the Food Standards Agency, agreed with expert recommendations to fortify bread or flour with folic acid.
Since then, at the request of the Chief Medical Officer, an expert working group on folate has been considering the results of recent trials looking at the effect of folic acid on the risk of some types of cancer.
The group is expected to report back to Sir Liam Donaldson this summer.
Folic acid is a synthetic form of folate, a B vitamin found in a wide variety of foods including liver and green leafy vegetables.
Pregnant women and those trying to conceive are already advised to take folic acid supplements to reduce the risk that their baby will have a "neural tube" birth defect like spina bifida.
But uptake is not ideal, particularly because some pregnancies are unplanned and can go unnoticed for some weeks.
The latest work suggests folic acid also cuts the risk of baby heart defects.
In the seven years after fortification was introduced there was a 6% drop per year in the birth prevalence of severe heart defects.
This compares with a 9% drop in neural tube defects.
Writing in the BMJ, lead author Professor Louise Pilote of McGill University in Montreal, said: "Given that severe congenital heart defects require complex surgical interventions in infancy and are associated with high infant mortality rates, even a small reduction in the overall risk will significantly reduce the costs associated with the medical care of these patients and the psychological burden on patients and their families."
Weighing the risks
The British Heart Foundation said the risks and benefits of fortification must be carefully weighed.
A spokeswoman said: "This Canadian study shows that when folic acid was added to flour and pasta the number of babies born with certain severe heart conditions was reduced.
"While the decrease in babies born with heart conditions during this time is statistically significant, many children were still born with congenital heart disease.
"This must be taken into account when considering the benefits of routinely introducing folic acid to flour and pasta in the UK.
"Especially because routine introduction could pose a risk to some elderly people as potentially dangerous vitamin B12 deficiency can be masked by high intake of folic acid."
Dr Sian Astley, a scientist for the Institute of Food Research, said: "Personally, I do not think mandatory fortification is the way forward. It is like using a sledge hammer to crack a nut.
"It would reduce ill health in children but there are cautionary issues.
"An alternative would be to fortify only certain foods and clearly label them so consumers can make the choice. Co-fortification with other B vitamins would be another sensible option."
She said the IFR believes there is still insufficient evidence to make a decision about whether the benefits of fortification would outweigh the risks.