The Prime Minister's chief science adviser is calling for the mandatory addition of folic acid to packaged bread, saying it could prevent about 10 babies a year from being born with a neural tube defect.
Sir Peter Gluckman and the Royal Society Te Apārangi have today released the results of a study into the benefits and risks of the folic acid fortification of food, as requested by the Ministry of Health last year.
While the expert panel unanimously agreed packaged bread should be fortified with folic acid, they stopped short of suggesting it be mandatory for all bread.
"If you can make for healthier babies, why not," Gluckman said.
But bakers would still be able to choose to produce artisan loaves without the supplement if the Government was to go ahead with the recommendation.
"The committee came to the view it was probably best to allow people some choice," he said.
The report found compelling evidence of lower rates of neural tube defects associated with folic acid fortification but no evidence to link it to neurological or cognitive decline, diabetes, or cardiovascular disease.
Most data also showed no link to increased cancer risk at the levels of folate that would be present in the fortification of food, nor was there evidence unmetabolised folic acid was harmful.
The evidence for fortification was "overwhelming" but the number of women of child bearing age who had sufficient folate levels was "disappointingly low" at only 16.2 per cent, Gluckman said.
The most recent data showed that in 2013, 18 babies were born with the defect and six others were still born.
Another 27 pregnancies were terminated when the defect was picked up in scans.
Others likely ended in spontaneous miscarriages before it was detected.
It was estimated that between 2008 and 2015, an average of 10.3 babies per 10,000 would have the defect.
Neural tube defects are severe birth defects that can lead to miscarriage, stillbirth or life-long and usually serious disabilities.
Many countries, including Australia already mandate the fortification of staple foods with folic acid to reduce the rates of neural tube defects but New Zealand relies on the industry to voluntarily add the supplement.
A 2012 model by the Ministry for Primary Industries estimated that mandatory fortification of bread with folic acid would prevent 18-24 cases a year compared about 10 more than if only 50 per cent of bread was fortified.
In 2016 only 38 per cent of all packaged bread had the supplement added.
But Gluckman said the number was likely to be higher when you took into the account the number of abortions that would be avoided and the lower number of miscarriages likely to occur.
In Australia the number of neural tube defects fell by 14.4 per cent following the implementation of mandatory fortification, which equated to a reduction of about 14 cases a year.
In Canada, it also resulted in a decrease in the number of children born with spina bifida, congenital heart defects and cleft lip.
But across Europe, where fortification was voluntary, there had been no noticeable decrease in instances of neural tube defects.
The only adverse effect of folate discovered was limited and weak evidence from genetic studies which suggested higher blood folate levels might be associated with increased risk of prostate and colorectal cancer, but decreased risk of breast and total cancer.
But, other approaches were also needed, with research showing women were now eating less bread.
AUT Professor of Nutrition Elaine Rush said ideally women would get their folate intake from foods that naturally contained it such as green leafy vegetables, dried beans and whole grain flours.
"Environmental measures in addition to the fortification of bread, that would reach the most vulnerable in society, could include removing the GST on fruit and vegetables, building more community gardens, paying a living wage and reducing homelessness, overcrowding and child poverty," she said.
Dr Andrew Marshall, Paediatrician at Wellington Regional Hospital and member of the MPI Folic Acid Fortification Group, said he believed the fortification of flour, rather than bread, would be more effective and cost efficient."
What is folate?
Folate is a B vitamin and folic acid is the synthetic form of it.
Why is it important?
Folic acid is needed for the proper development of the human body. It is involved in producing the genetic material called DNA and in numerous other bodily functions.
What foods are high in folate?
Foods naturally high in folate include leafy vegetables such as spinach, broccoli and lettuce; asparagus, bananas, melons, lemons, beans, yeast, mushrooms, beef liver and kidney, orange juice and tomato juice.