Putting folic acid in bread could prevent hundreds of miscarriages a year, public health experts say - an "iceberg of heartbreak" invisible to most New Zealanders.
The Ministry for Primary Industries recently called for feedback on putting folic acid in all non-organic bread or bread-making flour (a process called fortification), which it estimated could prevent around 5 to 9 neural tube defect-affected pregnancies a year.
• Read the full investigation into New Zealand's folic acid debate and legacy by clicking here
The NZ College of Public Health Medicine, however, believes as many as 200 miscarriages a year could also be prevented by the change.
The huge difference is because the MPI estimates included only live births, stillbirths and terminations. The college includes spontaneous miscarriages earlier in pregnancy which it believes could be prevented if a mother's folate intake was higher.
"We estimate that there are 15 to 21 times as many neural tube defect-affected cases of spontaneous miscarriages each year as there are live births or foetal deaths (including induced terminations)," the college stated in its submission to MPI, obtained with 100 others under the Official Information Act.
The NZ Medical Association, with more than 5000 members, also submitted that the high number of miscarriages are "a serious new item to factor when considering the cost-effectiveness of fortification".
Dr Scott Metcalfe, chair of the college's policy committee, likened the number of miscarriages that might have been prevented if plans for mandatory fortification had gone ahead in 2009 to "an iceberg of heartbreak".
"It's under the radar, and a loss of hopes and dreams."
MPI admits benefits are likely to be higher than estimated, but says it "deliberately took a conservative approach to ensure the net benefits are justifiable".
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"Many benefits were considered in the analysis, but were not quantified due to the difficulty in accurately quantifying and monetising values, or immateriality," said Bryan Wilson, deputy director-general of NZ Food Safety, a division of MPI.
Sapere Research Group, the company used to help MPI's analysis, had spoken to Metcalfe about the college's submission, including the relationship between folic acid fortification and spontaneous miscarriage.
"The paper referenced by the NZ College of Public Health Medicine submission provides evidence for a trend between increased folic acid intakes and decreased rates of spontaneous miscarriage," Wilson said.
"However, the authors note that the association was driven by supplement use rather than from food. Based on this evidence, we acknowledge that there may be a positive impact on spontaneous miscarriages from increased fortification.
"The evidence is not sufficient to justifiably, and accurately, quantify this potential benefit in our conservative estimates. As such, this benefit has been considered as a possible and unquantified benefit in the updated cost-utility analysis, post-consultation."
Another chapter in NZ's folic acid debate
Getting enough folate, a natural B vitamin found in foods such as leafy green vegetables, before and in early pregnancy can considerably reduce the risk of neural tube defects (NTDs), which include spina bifida and often lead to severe disability, death or termination.
It's very difficult to get enough from diet alone, and women are advised to take folic acid tablets.
However, many don't, and more than half of pregnancies aren't planned - a proportion that rises for young mothers (83 per cent), Māori (75 per cent) and Pacific Kiwis (71 per cent). When those women realise they're pregnant it's often too late - the neural tube closes 15 to 28 days after conception.
For this reason, NZ and Australia agreed to mandatory folic acid fortification from 2009, but the new National Government backed out after an opposition campaign by bakers and the Food & Grocery Council (an industry lobby group), who warned of unknown effects of "mass medication".
New Zealand currently has a voluntary system that aims to have up to half of packaged bread fortified with folic acid (about 38 per cent currently is).
Last year, MPI called for feedback on three options: keep the status quo; boost the voluntary target to 80 per cent; or mandatory fortification of all non-organic bread, wheat flour for bread-making, or wheat flour.
In doing so, it cited a comprehensive 2018 report by the PM's chief science adviser and the Royal Society that concluded unequivocal benefits of mandatory fortification of packaged bread outweighed any potential adverse health effects.
"If mandatory fortification of bread had occurred in 2009, it is estimated that 120 to 171 pregnancies affected by a neural tube defect could have been prevented over the last 10 years," MPI estimated.
Just over 100 submissions were released to the Weekend Herald, two-thirds of which clearly supported some form of mandatory fortification (most wanted bread-making flour fortified). Another 17 were opposed/wanted a voluntary system, and the rest were undecided, neutral or unclear.
Those in favour include the Ministry of Health, Auckland Regional Public Health Service, DHBs including Southern, Canterbury, Capital & Coast and Nelson Marlborough, Plunket, the Medical Association, the College of Obstetricians and Gynaecologists, the Paediatric Society, College of Physicians, Nurses Organisation, College of Midwives, Dieticians NZ, Consumer NZ, scientists, health academics and workers, including doctors and midwives.
Many stressed how mandatory fortification would particularly benefit Māori and Pacific, who have higher NTD rates.
Dr Richard Vipond, medical officer of public health at Waikato DHB, said the 2009 policy reversal "led to New Zealand falling behind other countries, further failings under Te Tiriti o Waitangi, and an ineffective voluntary approach".
The Perinatal and Maternal Mortality Review Committee, tasked by the Government with reviewing all deaths of babies and mothers, strongly supported mandatory fortification. A review of its records found that, of 21 women whose babies died of an NTD, only one took preconception folic acid.
"It is not women and their whānau who are 'the problem', but rather an under-resourced, overly complex and inadequately responsive maternity system," the committee chair, Dr John Tait, submitted.
Opposition - and some support - from the food industry
One of the most outspoken opponents was the Baking Industry Association of NZ, which said the incidence of NTDs was declining already, and MPI's data was wrong and misleading.
"Rather than medicating the population (including the males for whom the impact is not part of the discussion), continued education has proven itself to be key," the association wrote.
The Food & Grocery Council, a vocal opponent in the past and which represents food manufacturers, wants the voluntary system to continue in the interim while more consideration is given to what it says is emerging evidence of possible health risks.
It says those risks include over-consumption of folic acid including by children, whether an elderly person with high folate but low vitamin B12 levels could have faster cognitive decline and what unmetabolised folic acid might do to the nervous system.
A joint submission by the NZ Flour Millers Association and the NZ Association of Bakers - representing the big companies - supported the status quo, including because of worries mandatory fortification would lead to further declines in bread consumption.
However, the associations stated that, if mandatory fortification was opted for, their preferred option was via flour or dough improvers (including bread concentrates and premixes).
There was some food industry support: Kraft Heinz and Woolworths NZ made submissions in favour of mandatory fortification.
MPI's folic acid work was put on hold because of the whole-of-government Covid-19 response, and says "priorities are still being considered, given we have only recently moved to national alert level 1".