Bakers voluntarily mixing folic acid into some breads has reduced the risk of babies being born with neural tube defects including spina bifida, an Otago University study has found.
One of the researchers now says going a step further and compelling bakers to add the vitamin would lead to even greater gains.
More than 60 countries require folic acid to be added to foods - usually bread, flour or grains, but also cooking oils in some countries.
New Zealand was on track to join them in 2009, under a transtasman regime, until the Government opted out at the last minute, deferring a decision on mandatory additions to bread to last month, then September.
It was swayed by a food industry campaign against "mass medication" of the food supply and fears of links - later dismissed by the Prime Minister's chief scientific adviser Sir Peter Gluckman - between folic acid fortification and cancer.
The baking industry lobbied for consumer choice, but offered voluntary fortification instead.
The Ministry for Primary Industries (formerly Agriculture and Forestry) is to produce a discussion document for a round of public consultation before Food Safety Minister Kate Wilkinson makes her decision.
It also commissioned Otago University researchers, including Professor Murray Skeaff, to check both the folate levels in a random sample of women of child-bearing age and the amount of folic acid in breads from voluntary fortification.
The study found 59 per cent of women had blood concentrations of folate that were associated with "a very low risk of neural tube defect". This was more than twice the 26 per cent who were found to have this level in the 2008/2009 national adults nutrition survey.
It also found wide variations in the amounts of folic acid in the bread samples - most commonly too little - which has led to a commitment from the three baking companies involved to improve consistency.
Professor Skeaff said yesterday voluntary fortification of bread had contributed to the women's improved folate status, but just how much was unclear because of the concurrent increase in the number of breakfast cereals and other foods that had folic acid added to them.
"Folate status is improving through voluntary fortification, but there's no doubt mandatory [fortification] will improve it more. It will likely reach a lot more women because instead of just being approximately 30 per cent of breads, it will be all breads."
The Paediatric Society urged the Government to bring in mandatory fortification of breads immediately in light of the Otago study, which showed folate levels had improved to about "half-way".
The society said voluntary fortification might reduce the number of neural tube defect pregnancies per year to 50, from the 75 that were estimated to occur previously. Mandatory fortification could reduce the tally to 30, the number that were unpreventable.
"Three slices of fortified bread per day is all it takes, in addition to an otherwise healthy diet."
The Organisation for Rare Disorders also wants a mandatory regime, with exemptions for a small number of products from each baker.
Annette Campbell, who is the spokeswoman for the Association of Bakers and CEO of Couplands Bakeries, would give no hint of the major bakers' final position, saying the ministry's working group and public consultation must be allowed to run their course.
Toddler's mum backs fortification
Kayla Smith, 2, has to use a little walking frame to get around.
The Hawkes Bay toddler was born with spina bifida, in which the spine fails to form properly before birth.
"She can walk if she's holding both of your hands," says Kayla's mother, Julie Smith, who supports mandatory fortification of bread with folic acid. "She couldn't stand up on her own.
"She can walk quite well, she runs with her walking frame, but the balance and strength to hold her body up, she's still working on that."
Kayla has had two operations - one shortly after birth to close her spine and the second to install a device to drain excess fluid from her brain into her abdomen. She will probably need another spinal operation as she grows.
Mrs Smith - whose 6-year-old daughter does not have spina bifida - said that although the future of Kayla's physical development was uncertain, she would probably be able to walk.
"She's on the lower end of problems [for children with spina bifida]. There's lots of other kids who would never get to walk and have a lot more problems."
Mrs Smith took multi-vitamin supplements before Kayla was conceived and during the early pregnancy so is at a loss to explain why spina bifida occurred.
"Maybe she would have been way worse off if I hadn't been doing that."
She supports the proposal to require commercial bakers to add folic acid to bread.
"If there's a way to get folic acid into people's diets so that that's taking that precaution for everyone, then I think it's worthwhile."
Mrs Smith and her husband Craig say that despite her difficulties, Kayla is a happy girl.
* Folic acid is the synthetic form of folate, an essential B-group vitamin that is present in leafy vegetables, citrus fruits, wholemeal bread, yeast, liver and legumes.
* The Health Ministry recommends women take a folic acid supplement for at least a month before conception and during early pregnancy to reduce the risk of neural tube defects in the fetus, including spina bifida.
* Because nearly half of pregnancies are unplanned, fortification of common foods has been debated in New Zealand for a decade as a way of improving the folate status of all child-bearing women.
For the Spina Bifida Association, see facebook.co.nz