Adding folic acid to bread will prevent babies from being born with birth defects without any risk of side-effects, a new report to the Ministry of Health has found.
Released publicly on Friday, the report's contents were delivered to the Ministry of Health in June. It says 10 cases of neural tube defects a year could be prevented if folic acid was a mandatory ingredient in bread.
"No evidence was found to link the use of folic acid supplements or fortification to increased risks of neurological/cognitive decline, diabetes, or cardiovascular disease; nor was there evidence that unmetabolised folic acid is harmful," the report says.
"While the absolute number of babies born or pregnancies terminated with neural tube defects are low, the social emotional and economic costs of such births are high, and folate-fortified bread will reduce the number affected."
The Labour-led Government in the 2000s planned to make folic acid a compulsory ingredient in bread, but the idea was scrapped under National. Then-Prime Minister John Key said he was "not convinced" of the health benefits.
"People can no longer use as an excuse that we don't know if folic acid would be beneficial," Otago University professor of human nutrition and medicine Jim Mann told Newshub. "That argument has gone away."
Former chief science adviser to the Prime Minister Sir Peter Gluckman, who co-authored the research, says there's no reason it shouldn't be added in the baking process.
"If you can make for healthier babies, why not?" Sir Peter told Newstalk ZB.
Neural tube defects include spina bifida and anencephaly, which is when a baby is missing parts of its brain and skull. Many never make it as far as birth - the mothers miscarrying or opting for an abortion instead.
Prof Mann says if it's in bread, women who have unplanned pregnancies won't have to worry about not having taken supplements because it's likely they'll be getting the recommended dose of folic acid from bread.
"We know that a lot of pregnancies are unplanned, and we know that even with planned pregnancies people don't start taking folic acid supplements when they are thinking of conceiving."
Though the report says the benefits of mandatory folic acid in bread outweigh "any possible adverse effects", it stops short of recommending it be compulsory for all varieties - just packaged bread.
"Adopting this recommendation will ensure many more women will have adequate folate status to reduce the risk of neural tube defect, but ensures access to artisan breads for people who might be concerned about possible, but unproven, adverse effects."
In 2016, around 38 percent of packaged breads had folic acid added, the report says, but with a lot of variability - some having more than the recommended dose.
Australia went ahead with mandatory fortification when New Zealand chose not to. The report says there has been a significant fall in neural tube defects since then.
Other countries which introduced fortification have also seen drops, while those that have no compulsory regime haven't.