Photo of dietitian Ursula Arens

By Ursula Arens, Freelance Nutrition Writer

Discussion about fortification of flour with folic acid is back in the media headlines. This is surprising. There is general agreement among nutrition experts that, the introduction of mandatory folic acid fortification into flour, is welcome. But there is now fierce debate on the more-or-less; how much folic acid should be added to all wheat flour (other than wholemeal) sold in the UK? A few most expert academics and practitioners have critiqued implementation proposals issued in late 2022 as, ‘Not enough!’

The research is yawningly old, and no subsequent research has challenged the observations first made by the Medical Research Council (MRC) Vitamin Research Group in 1991, that improved folic acid status prior to pregnancy results in a significant reduction (about 80%) in the subsequent risk of foetal neural tube defects (NTDs). These severe developmental abnormalities occur within the first month post-conception, and currently about 1000 pregnancies per year are affected in the UK. NHS advice to all women considering pregnancy, is to take a daily folic acid supplement (400ug) before, and until week 12 of pregnancy.

But not all pregnancies are perfectly planned; nearly 50% are ‘surprise’ events, so supplement taking will not protect many women. In contrast, food fortification as a strategy supports greater intakes of nutrients in whole populations, including risk groups. The mandatory addition of folic acid to wheat flour and other frequently consumed foods is now required in about 90 countries (most recently in New Zealand and Malaysia) and has been in place for more than 20 years in the United States. Close monitoring of folic acid fortification in many countries confirms the observations of the reduced subsequent incidence of NTDs, and there are no reports of subsequent concerns in relation to other health issues within populations.

The most authoritative UK nutrition expert committee (Scientific Advisory Committee on Nutrition – SACN), has repeatedly reviewed the proposed introduction of mandatory folic acid fortification, and affirmed their support for such a policy in a report they issued in 2017. Perhaps due to greater freedoms to modify legislation post-Brexit, the UK government decided to implement the clear policy support for folic acid fortification. In September 2021 the Department for Environment, Food and Rural Affairs (DEFRA) issued proposals for folic acid fortification, and a year later, implementation proposals were released. Why have these sparked such fierce debate?

Some background. Reference Nutrient Intakes (RNI) are the amounts of a nutrient that should be sufficient for nearly all people in a population. For folate (the natural food form of folic acid), the UK RNI is 200ug daily. The Upper Level (UL) is the maximum level of chronic intake of a nutrient that is judged to be unlikely to pose any adverse health effects, and for folic acid is 1000ug. Folates are found naturally in some foods: citrus fruits, green vegetables, beans and pulses, and liver, but it is difficult to achieve the levels suggested as protective for NTDs from foods alone. While there is also voluntary fortification of some breakfast cereals, typical dietary intakes of adult women in the UK are about 200ug daily. The DEFRA proposals recommend the addition of 250ug of folic acid to 100g of wheat flour. Modelling and calculations predict that such amounts would result in a reduction in the rates of NTDs by 15-22% a year.

Professor Sir Nick Wald was the epidemiologist who led the initial MRC study in 1991. He and several expert obstetricians and neurologists attended a briefing organised by the Science Media Centre, called for folic acid to be applied to all flours (including wholemeal), and to other staple foods such as rice. They have also called for fortification at much higher levels of 1000ug (1mg) because the predicted protective effects of the four-fold higher fortification level would be about 80% rather than 20%.

There have been many policy debates of the benefits and effectiveness of targeted supplement promotion versus mass fortification of foods, as ways to enhance nutrient intakes in populations to reduce deficiencies and disease. Fortification is less targeted, and provides lower levels of nutrients, but is cheap, benefits nearly all people in populations, and does not require specific education or messaging campaigns (in the way that promoting supplement use does). Supplement dose nutrients within fortified foods would be a new interpretation, and the UK Committee on Toxicity (CoT) have previously recommended that fortification policies should limit the proportion of population whose intakes exceed the Upper Level for folic acid (1000ug per day) due to a lack of data on long-term health effects.

The charity Shine, supports individuals and families affected with NTDs, and is keen to see folic acid fortification legislation implemented as soon as possible. Dietitians and nutritionists now await final decisions on amendments to future Bread and Flour Regulations. And even when these are issued, implementation periods usually allow two years before any legal enforcement for non-compliance can occur. The bread you buy in 2025, will contain folic acid. But how much?