The research team put forward a case for abolishing the upper level of intake for folate, currently set at 1 milligram per day (mg/day), calling the limit ‘a barrier to the wider introduction of mandatory fortification of flour with folic acid to prevent neural tube defects.’​

“Failing to fortify flour with folic acid to prevent neural tube defects is like having a polio vaccine and not using it,”​ said lead author Professor Sir Nicholas Wald from the Wolfson Institute of Preventive Medicine at Queen Mary University of London.

“Every day in the UK, on average two women have a termination of pregnancy because of a neural tube defect and every week two women give birth to an affected child.”​

Despite successive recommendations, the UK has not introduced mandatory fortification. This is in contrast to the US, which introduced mandatory folic acid fortification of cereals in 1998.

A ’flawed’ analysis ​

Writing in the journal Public Health Reviews, ​the paper cites ‘flawed’​ analysis that lead people to believe having a folate intake above an ‘upper limit’​ was harmful to health.

The analysis, conducted by the US Institute of Medicine (IOM), now known as the National Academy of Medicine, also concluded that treating individuals with vitamin B12 deficiency with higher doses of folic acid might lead to an increased risk of neurological damage.

This observation has been challenged by a re-analysis of the data, which could find no relationship between dose of folic acid and the development of neurological damage.

Current fortification efforts in the UK are restricted to the inclusion of iron, calcium and other B vitamins (niacin and thiamin) in white flour.

Fortification of while flour with folate may well provide a protective population safety net, particularly for expectant mothers, who are advised to start taking a daily folic acid supplement, but rarely do so,

Folic acid fortification is primarily to prevent the 1 in every 500-1,000 pregnancies that result in serious neural tube birth defects such as anencephaly and spina bifida.

“From 1998, when the US introduced mandatory folic acid fortification, to 2017, an estimated 3,000 neural tube defects could have been prevented if the UK had adopted the same level of fortification as in the US,” ​said co-author Professor Joan Morris from the Wolfson Institute of Preventive Medicine at Queen Mary.

“It’s a completely avoidable tragedy.”​

Multiple voices of support​

The authors’ conclusions mirror those of other experts, who have called on the UK Government to fortify flour.

Other voices in support include those from the Royal College of Obstetricians and Gynaecologists and the British and Maternal Foetal Medicine Society.

Professor Neena Modi, president of the Royal College of Paediatrics and Child Health, called the research “a game changer for fortification in allaying concerns about exceeding an upper limit of 1mg/day”.​

“In the early stages of pregnancy when neural tube defects arise, many women do not know they are pregnant, others may be unaware of the importance of taking folic acid, or may forget, so fortification of flour, which is harmless if consumed by children and adults, is a logical answer to a problem which can have catastrophic consequences.​

“Around 80 countries already fortify foods and report significant reductions in neural tube defects. It’s a move backed by food manufacturers and other experts. ​

“The Government now needs to implement this simple, highly effective public health measure.”​

UK Government action to date​

The UK Government last provided an update to folic acid back in July last year. Here, its Scientific Advisory Committee on Nutrition (SACN) took a cautious approach, advising that its previous recommendation remains unchanged.

The Working Group on Folic Acid was adamant evidence published since SACN’s previous reports on potential adverse effects of folic acid, does not provide a substantial basis for changing this recommendation.

“Mandatory fortification should only be introduced alongside restrictions on voluntary dietary fortification with folic acid and clear guidance on the use of folic acid supplements,” ​the Committee said.

“This was to ensure no increase in the numbers of people with intakes above the Guidance/Tolerable Upper Intake Level (GL/UL). These recommendations remain unchanged.” ​

Source: Public Health Reviews​

Published online ahead of print: doi.org/10.1186/s40985-018-0079-6​​

“Public health failure in the prevention of neural tube defects: time to abandon the tolerable upper intake level of folate.”​

Authors: Nicholas Wald, Joan Morris and Colin Blakemore.