Résumé
Following a request from the French Directorate General for Health, ANSES was asked to deliver a scientific opinion on the state of the evidence on the prevention of neural tube defects (NTDs) by increasing vitamin B9 intake. The opinion estimates the prevalence of NTDs in France using data collected between 2012 and 2021 from five French registries reporting a mean prevalence of 13.5 per 10 000 births. The efficacy of vitamin B9 supplementation and food fortification was evaluated by conducting systematic reviews of human studies. The opinion also provides a comparative analysis of international vitamin B9 fortification strategies, followed by simulations to assess fortification levels and their potential to reduce inadequate vitamin B9 intake in France. The Expert Committee and ANSES concluded that fortifying flour (both refined and whole grain) with 200 μg of folic acid per 100 g would enable 90% of women to meet the Dietary Reference Value for adults and ensure a mean intake exceeding the adequate intake of 600 μg/day of dietary folate equivalents during pregnancy. However, this measure would not replace the recommendation for women to take a folic acid supplement (400 μg/day) from the moment they try to conceive until 12 weeks of pregnancy. ANSES further recommended initiating a public consultation of all the stakeholders.