There are fresh calls for the government to fortify flour with folic acid in the UK to help protect newborns from common birth defects.
A new study concludes highest dose of the B vitamin, which can avoid spina bifida in unborn babies, will not harm the general public.
Folic acid is added to flour in more than 80 countries worldwide, but the UK has previously held off.
Pregnant women are advised to take folic acid tablets, but many don’t.
Fortification would offer extra cover-up, say experts.
The idea of mandatory fortification has already been backed by health ministers in Wales, Scotland and Northern Ireland, but not England.
The latest research, published in Public Health Reviews, claims proof for restriction uptake of folic acid to no more than 1mg a day is out-of-date and flawed.
The new re-analysis of the data detects no connection between higher levels of folic acid and damage, although some say there is still not enough proof to say castle is entirely safe.
Prof David Smith, an expert in pharmacology at the University of Oxford, said: “The matter has not been resolved.”
Nutrition expert at King’s College London, Prof Tom Sanders, said there was “overwhelming” evidence in support of the case for folic acid fortification to prevent neural tube defects.
A neural tube defect involves abnormal development of the brain, spine or spinal cord. Approximately one in 1,000 pregnancies in the UK is affected.
Researchers say the cost of adding folic acid would be “pennies”.
Under the government’s 1998 Bread and Flour regulations, white flour is already fortified with iron, calcium and some vitamins – at a cost of simply 71 p per tonne of flour.
Lead author, Prof Sir Nicholas Wald, of the Wolfson Institute of Preventative Medicine, said: “Fortification would be a major saving.
“Failing to fortify flour with folic acid to prevent neural tube flaws is like having a polio inoculation and not using it.”
Study co-author Prof Sir Colin Blakemore, from the University of London, said: “If you can dispel the debate for damage … you are left merely with the facts of the case that not fortifying flour denies a proven and clearly benefit to a significant proportion of the population.”
The US has find a 23% fall in pregnancies with neural tubing flaws( spina bifida and anencephaly) since the implementation of policies was introduced in 1998.
Folic acid results naturally in dark green leafy vegetables but research has suggested three-quarters of women across the UK don’t consume sufficient levels.
It is voluntarily added to some breakfast cereals and spreads, but it is very difficult for pregnant women to get enough from diet alone.
A Department of Health and Social Care spokesperson said: “We want mums-to-be to have healthy pregnancies, and NHS guidance is that girls scheming a pregnancy should take a daily supplement of 400 micrograms of folic acid before conception and until the 12 th week of pregnancy. We also recommend eating more folate-rich foods to reduce health risks of neural tube defects.”
Good sources of folic acid:
spinach, kale, Brussels buds, cabbage, broccoli beans and legumes( e.g. peas, blackeye beans) yeast and beef extracts oranges and orange juice wheat bran and other whole grain foods poultry, pork, shellfish and liver fortified foods( e.g. some brands of breakfast cereals – check the label ).