The mandatory addition of folic acid to flour has the potential to prevent neural tube defects

According to a new paper by Professor Sir Nicholas Wald of UCL, the UK Government’s current proposal to fortify one type of flour with folic acid is inadequate because it suggests a low dose that would fail to prevent hundreds of cases of severe birth defects each year.

The article, which was published in The Journal of Medical Screening, argued that increasing the dose from what is currently proposed would prevent approximately 80% of neural tube defects, which cause life-threatening and disabling spinal conditions such as spina bifida and anencephaly. The proposed policy would only prevent approximately 10%.

In the first four weeks of gestation, the neural tube forms the earliest parts of the brain and spine, typically before the mother is aware she is pregnant. Folate, or vitamin B9, deficiency can result in neural tube defects. Folic acid is a stable synthetic form of folate. While it is recommended that women take folic acid supplements prior to and during the early stages of pregnancy, many mothers fail to do so.

In September of last year, the government of the United Kingdom announced plans to fortify non-wholemeal flour with folic acid in order to better prevent neural tube defects, joining approximately 80 other nations that already do so.

Professor Wald (UCL Institute of Health Informatics) led the international trial (the MRC Vitamin Study) that definitively established folate deficiency as a cause of neural tube defects over three decades ago. He said: “Mandatory folic acid fortification of flour has the potential to significantly reduce the number of disabilities and premature deaths resulting from neural tube defects. However, the level of defence currently proposed is merely symbolic. It makes no sense to implement a policy that prevents only 10 percent of neural tube defects when 80 percent could be prevented without risk by increasing the level of fortification and extending it to wholemeal flour and grains.

The United Kingdom has the opportunity to lead the world in preventing neural tube defects through fully effective flour fortification, as no other country currently fortifies flour to the level proven to be the most effective.

In the paper, Professor Wald noted that there were concerns that a higher dose of folic acid could be neurotoxic, but that these concerns were misplaced because they were based on a flawed study. Another concern was that higher doses of folic acid could mask the symptoms of a different vitamin deficiency (B12 deficiency). However, this concern is no longer relevant, according to the paper, as tests can now detect B12 deficiency in symptomatic patients early enough to administer effective B12 treatments.

He stated that the UK Government should aim for a folic acid intake of 4mg per day, the same amount given to women who participated in the landmark MRC Vitamin Study. This would mean that the level of folic acid fortification should be increased from approximately 0.2mg per 100g of flour to approximately 1mg per 100g of flour.

Why wait for antenatal screening for neural tube defects and selective abortion, argued Professor Wald, when it was possible to prevent the majority of these cases in the first place through fortification?

Between 1992 and 2020, the paper estimates that effective folic acid fortification of flour could have prevented 6,7 million cases of neural tube defects worldwide.

Primary prevention spares families the anguish of a positive screening result and the arduous decision of an abortion if the foetus is affected. Priority should be given to effective primary prevention, with antenatal screening serving as a backup.”

Currently, in the United Kingdom, women who may become pregnant or are planning a pregnancy are advised to take a folic acid supplement prior to conception and continue doing so until the 12th week of pregnancy. In a survey of half a million women in England, however, only one-third reported following this recommendation, with a smaller proportion of less affluent women doing so. Adequate fortification would prevent this health disparity by eliminating the need for dietary supplements.

In the absence of fully effective fortification, folic acid supplements are still necessary; however, the paper suggests that current recommendations should be revised. Most women are advised to take a daily tablet containing 0.4mg of folic acid, while women who have previously had a pregnancy affected by neural tube defects are advised to take a higher dose of 4mg or 5mg, which is only available with a doctor’s prescription in the UK and certain other countries. The paper calls for the recommendation to be revised so that all women are advised to take the higher, over-the-counter dose.

Prof. Wald stated: “Global impact would be substantial if all flour and grains were effectively fortified. It would have a dramatic impact on the prevention of serious birth defects and associated stillbirths, neonatal deaths, miscarriages, abortions, and the physical disability caused by spina bifida.”



Journal reference:

Wald, N.J., (2022) Folic acid and neural tube defects: Discovery, debate and the need for policy change. Journal of Medical Screening.


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