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The health benefits and risks of folic acid fortification of food

2018: This report reviews the health benefits and potential risks of adding folate (folic acid) to packaged bread to reduce the rate of neural tube birth defects in New Zealand. The evidence supports mandatory fortification.

This is a joint report of the Prime Minister's Chief Science Advisor Sir Peter Gluckman FRS FRSNZ and Royal Society Te Apārangi.

Download report: The health benefits and risks of folic acid fortification of food

Background

In 2017 the Ministry of Health requested the Prime Minister’s Chief Science Advisor (PMCSA), Sir Peter Gluckman, and the Royal Society Te Apārangi to formally review the health benefits and potential risks associated with folic acid fortification of food. The report was provided to the Ministry of Health in June 2018, prior to the end of Sir Peter’s mandate.

Many countries mandate the fortification of staple foods with folic acid to reduce the rates of neural tube defects. However, New Zealand relies on industry-led voluntary fortification of bread. This report was requested to provide government decision makers and the public with a comprehensive and up-to-date understanding of the available scientific evidence on the health benefits and any potential risks to human health of folic acid fortification of food.

Process

The scientific review was conducted in accord with a general process agreed between the PMCSA and the Society for such reports. The PMCSA appointed an experienced Research Fellow to undertake the primary research and literature reviews. The report was overseen by a Society-appointed panel of experts and a respected member of civil society as a lay observer, and was co-chaired by Sir Peter and Emeritus Professor Robert Beaglehole. There were multiple iterations and discussions over several months, leading to a draft report that was subjected to Ministry feedback and then international peer review.

Findings and conclusions

The report concludes that there is compelling evidence that mandatory folic acid fortification is associated with lower rates of neural tube defects, and that taking folic acid supplements at the recommended doses in pregnancy has no adverse effects on pregnancy outcome or the child’s health.

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 Panel reviewed data related to potential effects on cancer risk. Most data suggest no effect on cancer risks at the doses used in fortification. Some limited evidence from genetic studies of people with different folate metabolism suggests that higher folate levels may be associated with reduced risks of breast and overall cancer, but at the same time may also be associated with higher risks of prostate and colorectal cancer. The Panel discussed this issue in great depth over many months, and took this complex evidence into account in preparing its unanimous advice.

The Panel noted with concern continuing evidence of low levels of folate in women of childbearing age in New Zealand. Based on an overall assessment of the evidence, and also considering the need to ensure that disadvantaged people including Māori receive benefit, the Expert Panel unanimously concluded that the benefits of mandatory fortification of packaged bread with folic acid outweigh any possible adverse effects. Adopting this recommendation will ensure many more women will have adequate folate status to reduce the risk of neural tube defects, but ensures access to artisan breads for people who might be concerned about possible, but unproven, adverse effects.

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.

It is acknowledged that bread intake is not high in all communities and thus other means of fortification or supplementation should be encouraged. In addition, the Panel strongly encourages the continued use of folic acid supplements by pregnant women as recommended by their healthcare professionals, and encourages all women of childbearing age to ensure that their folate intakes are adequate.

Contributors

Royal Society Te Apārangi convened a panel to support the report. 

Expert Panel members

Professor Tony Blakely, MBChB, MPH, PhD, FAFPHM Research Professor, Department of Public Health, University of Otago, Wellington; Director, BODE and HIRP

Associate Professor Elana Taipapaki Curtis, FNZCPHM, MD, MPH, MBChB, BHB Director, Vision 20:20; Senior Lecturer, Medical, Te Kupenga Hauora Māori, University of Auckland

Professor Cameron Grant, MBChB, FRACP, PhD Professor of Paediatrics and Head of Department of Paediatrics: Child and Youth Health, University of Auckland; Paediatrician, Starship Children’s Health

Associate Professor Lisa Houghton, MSc, PhD Associate Professor, Department of Human Nutrition, University of Otago

Professor Ian Shaw, BSc (Hons), PhD, FRSC, CChem, FRCPath Professor of Toxicology, University of Canterbury

Mr Dean Stockwell, MBA, MTech (IM&E), BTech (Food), GAICD, CMInstD, FNZIFST Dean Stockwell Consulting

Panel lay observer

Ms Kerry Prendergast, CNZM Chair, Environmental Protection Authority

Panel co-chairs

Emeritus Professor Robert Beaglehole, MD, DSc, FRSNZ School of Population Health, University of Auckland

Professor Sir Peter Gluckman, ONZ, KNZM, FRSNZ, FMedSci, FRS Chief Science Advisor to the Prime Minister of New Zealand

Peer reviewers

Professor Dennis Bier, MD Professor of Pediatrics, Baylor College of Medicine; Director, Children's Nutrition Research Center, Texas Children’s Hospital, Houston, TX, USA

Dr Luz María De-Regil, DSc, MSc Vice-President, Global Technical Services, Nutrition International

Dr Jeff Fowles, PhD Tox-Logic Consulting, Santa Rosa, CA, USA

Professor Jim Mann, CNZM PhD DM FRACP FRSNZ Professor in Medicine and Human Nutrition, University of Otago, Dunedin, NZ

Professor Richard Martin, BMedSci, BM, BS, MSc, MRCGP, FFPH, PhD Professor of Clinical Epidemiology, Bristol Medical School, University of Bristol, Bristol, UK

Professor Kathleen Rasmussen, ScD, RD Nancy Schlegel Meinig Professor of Maternal and Child Nutrition, Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA

Professor Sir Nicholas Wald, FRCP, FRS Professor of Preventive Medicine, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK