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Folic acid fortification of non-wholemeal wheat flour in the UK

3 Oct 2021

Professor Mark Kilby explores the Government's decision to add folic acid to non-wholemeal wheat flour, and discusses why this is a major public health win.

In the past few weeks, the UK Government has announced it will introduce the mandatory fortification of non-wholemeal wheat flour with folic acid. In my view as a fetal medicine subspecialist, this is a major public health initiative that will positively lead to a reduction in neural tube defects (NTDs).

It’s been 30 years since the Medical Research Council Vitamin Randomised controlled trial demonstrated that 4mg folic acid taken by women trying to conceive and those in early pregnancy reduced the risk of a fetal NTD by 72%. By including it in non-wholemeal wheat flour, the hope is around 200 cases of NTDs in new-borns will be prevented each year – around a fifth of the UK total.

Studies have noted that ‘natural intake modification’ of the diet with foods rich in folic acid, would be unlikely to achieve a high enough daily intake to be associated with a reduction of risk of this anomaly. Therefore taking oral folic acid supplements or the folate fortification of food, such as flour, is necessary to achieve this public health goal.

National commissioned service for fetal surgery

It was with some excitement that I heard that in 2019, NHS England (after an extensive review of the literature, professional and public consultation) was initiating a national commissioned service for fetal surgery to repair the most severe form of spina bifida called myelomeningocele, in an attempt to reduce morbidity. This was after the Management of Myelomeningocele Study (MOMS) from the USA reported that, in selected cases:

  • prenatal surgical repair of this type of spina bifida reduced the risk of babies having brain malformations,
  • babies were half as likely to need a ventricular shunt, and
  • twice as many children were walking independently at 30 months as compared to the postnatal surgery group.

This initiative was welcome, but I felt a combination of personal emotion and professional confusion, as to why there was no corresponding public health initiative to supplement food with folic acid – a simple and cheap intervention to cause a fall of prevalence of these malformations.

Fortifying flour with folic acid

Fortification of flour was introduced in the USA in 1998 and has since been introduced in 80 countries since this time outside the EU. Fortification of flour was introduced at a level of 1.4μg/100g and was demonstrated as being effective at significantly reducing the prevalence of NTDs and potentially also reducing the risks of other seriously morbid diseases of pregnancy, such as fetal growth restriction.

Other countries, such as Chile, have adopted fortification of folic acid in flour to higher levels than in the USA (to 2.2 μg/100g) and noted a significant incremental reduction in NTD prevalence. Based on this evidence and other sources, the World Health Organization (WHO) and the Food and Agricultural Organization of the United Nations (FAO) recognised that the purpose of food fortification (i.e. the process of adding essential micronutrients to foods) is "to improve the nutritional quality of the food supply and to provide a public health benefit with minimal risk to health".

The situation in the UK and EU

Many countries within the EU, and the UK, have been very slow to implement this effective and relatively cheap public health intervention. Therefore, over the last 30 years, the prevalence of NTDs has not decreased in many European countries and the average rate of NTDs in Europe has been estimated at ~1.6 times higher than in regions of the world with mandatory folic acid-fortification policies in place.

Concerns have focused upon possible unintended consequences such as the inadvertent masking of vitamin B12 deficiency in older people, allowing the associated irreversible neurological symptoms of that deficiency to progress. However, the US experience has indicated that this has not been the case. There have also been concerns related to possible epigenetic consequences of long-term exposure, but long-term investigation is ongoing.

A recent overview publication examining EUROCAT (congenital anomaly) data and estimating the effects of folic acid fortification has indicated that at best, 19,500 NTDs complicating pregnancies would have been prevented since 1998, if such flour fortification had been introduced in the UK. This has rekindled review of this health measure.

The COVID-19 pandemic has had significant adverse effects upon UK population mortality and morbidity. However, it has led to a refocusing upon the role of Public Health and the prevention, as well as the treatment of established diseases.

Although this blog post focuses upon the preventative role of folic acid on NTDs, we should all be encouraged there is evidence supporting more widespread benefits throughout childhood, adolescence and to preventing chronic disease in advanced age, including cardiovascular diseases, certain cancers, osteoporosis, and cognitive dysfunction. It is a very welcome initiative.

Mark Kilby is the Dame Hilda Lloyd Professor of Fetal Medicine at University of Birmingham and lead clinician at the Fetal Medicine Centre, Birmingham Women’s and Children’s Foundation Trust, UK. He is the Vice Chair of the RCOG's Genomics Taskforce (taking over as Chair in November 2021) and chair of the Scientific Advisory Committee (SAC).


  1. MRC Vitamin Study Research Group. Prevention of neural tube defects: results of the Medical Research Council Vitamin Study. Lancet. 1991; 338: 131-137.
  2. Wolff T et al. Folic acid supplementation for the prevention of Neural Tube Defects: An update of the evidence for the US Preventative Services Task Force. Ann Intern Med. 2009; 150: 632 - 639.
  3. Report of the Scientific Committee of the Food Safety Authority of Ireland. Update Report on Folic Acid and the Prevention of Birth Defects in Ireland. 2016.
  4. Morris JK et al. Prevention of Neural Tube Defects in Europe: A Public Health Failure. Front Pediatr. 2021; 9:647038: 1 - 9.
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  6. Qi YP, Hamner HC, Pfeiffer CM Berry RJ. The prevalence of low serum vitamin B-12 status in the absence of anemia or macrocytosis did not increase among older U.S. adults after mandatory folic acid fortification. J Nutr.2014;144(2):170-6.
  7. Haggerty P. UK introduces folic acid fortification of flour to prevent neural tube defects. Lancet 2021;398, 10307:1199-1201.
  8. Department of Health and Social Care; Welsh Government; The Scottish Government; Department of Health (Northern Ireland). Adding folic acid to flour. Date acessed: 1st October 2021.
  9. Department of Health and Social Care UK Government. Folic acid added to flour to prevent spinal conditions in babies. Date accessed: September 20, 2021.
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