Friday, 18 December 2015

The case for mandatory folic acid fortification?

The UK’s failure to fortify flour with folic acid has caused around 2000 avoidable cases of neural tube defects since 1998.  This is the conclusion of research published online today in the Archives of Disease in Childhood.

The researchers say that the UK should now follow the lead of the US and 77 other countries  in legislating for mandatory fortification of flour to curb the associated toll of fetal and infant death and disability.

Folic acid is a B vitamin which is vital for the formation of red blood cells.

The UK has rightly been cautious about making 'medicines' or dietary supplements mandatory.  In medical ethics we emphasise autonomy and the right to make decisions about one's health and treatment. Autonomy is a fundamental principle of modern medical ethics.  It sets a high ethical threshold, and a key concern must be that the benefits of mandating medicine should be sufficient to breach this fundamental principle.

To a large extent this is a utilitarian ethical calculus, the balance of benefits and potential harms, but there is another fundamental issue, and that is the extent to which the state should discharge a duty of care on behalf of those who cannot make decisions about their lives - in this case unborn children.

In relation to the ethics of mandatory fortifying of bread with folic acid the real question is whether it is necessary to discharge a duty to protect the unborn child.  If current strategies are failing, then we have a duty to consider other approaches.  These authors present convincing evidence that the current strategy isn't working.

We are dealing with appalling consequences. Neural tube defects, which are birth defects of the brain, spine, or spinal cord, include spina bifida, anencephaly, and encephalocele which can be profoundly disabling conditions.

In 1991 the UK Medical Research Council Vitamin Study showed that a supplement of folic acid taken before and during early pregnancy cut the risk of neural tube defects by around 72%.  That is a big difference.

The problem is that it is difficult to achieve a high enough level of folate from diet alone, so taking supplements or eating foods fortified with folic acid is a sensible option for women intending to become pregnant. It is the recommended option for women about to become pregnant.

In 1992 the Department of Health in England advised women to take folic acid supplements before pregnancy to reduce their risk of having a baby with a neural tube defect.  The problem is, as the study showed, most women don’t take them.  Another problem is that women don't necessarily know they are going to be pregnant, and sometimes they don't know initially that they are pregnant - so they don't take the supplement from the right time.

The current recommendation is that every woman considering pregnancy, and up to the 12th week of pregnancy is advised to take a folic acid supplement, or pregnancy specific vitamin supplement providing 400μg every day,   and that they should eat a diet rich in folates and folic acid from foods naturally containing the vitamin or from fortified foods.

But even with these recommendations, many women do not take folic acid supplements in early pregnancy, and it is argued that routine fortification of flour with folic acid is a simple way to increase folic acid intake for everyone.

Many countries have introduced mandatory fortification of flour with folic acid, resulting in  significantly reduced  numbers of neural tube defect births.  So why has the UK been so cautious?

The UK has been cautious in recommending this for a number of reasons. Firstly, although folic acid supplements can correct the anaemia caused by vitamin B12 deficiency, this masks the ongoing damage to nerves caused by B12 deficiency until irreversible nerve damage occurs. Older people are most at risk because uptake of vitamin B12 from diet reduces with age.  There is also conflicting evidence that folic acid might increase the risk of colorectal cancer in older people. This then is a balanced judgement of potential harms to some of the population against the proven benefits in pregnancy outcome.  There is, however, little evidence for this potential harm.

There is little evidence from countries with mandatory folic acid flour fortification that more people have developed nerve damage as a result of vitamin B12 deficiency since the flour had been fortified.

Thus, a key question is whether it would it make a fundamental difference if the UK followed some other countries in making folate-fortified bread mandatory. The answer from this study appears to be a resounding yes.

The authors of the study have estimated the number of pregnancies with neural tube defects that would have been prevented had the UK opted to fortify flour with folic acid in 1998—the year that the US adopted this policy (140 µg of folic acid per 100 g of cereal grain).

They used data on the number of diagnoses of neural tube defects and associated terminations of pregnancy for the period 1991 to 2012 from EUROCAT, a European network of registers that track birth defects, which includes the British Isles Network of Congenital Anomaly Registers (BINOCAR).

The prevalence of pregnancies with a neural tube defect during this timeframe was 1.28 per 1000 births. Most (81%) of the affected pregnancies were terminated.

But unlike the USA, there was no significant change in the prevalence of pregnancies with a neural tube defect in the 14 years between 1998 and 2012, nor were there any significant changes in the prevalence of spina bifida, anencephaly with or without spina bifida, or encephalocele, when analysed separately.

The researchers estimated that there would have been 2014 fewer pregnancies with a neural tube defect in the UK had the US policy been adopted: 1798 fewer in England and Wales; 152 in Scotland; and 64 in Northern Ireland. This equates to an estimated fall in prevalence of 21% between 1998 and 2012, they say.

In the USA, the prevalence of pregnancies with a neural tube defect has fallen by around 23% since 1998, and in Chile, where the level of flour fortification is even higher, at 2.2 µg/100 g, the prevalence has fallen by 36%.

“The failure of Britain to fortify flour with folic acid has had significant consequences,” say the researchers, who emphasise that its addition is “remarkably safe,” with fears that fortification might increase the risk of cancer not substantiated by the evidence.

The longer Britain holds back on this cost effective mandatory supplementation, the more affected pregnancies there are likely to be each year—around 150, nearly all of which would result in the birth of severely disabled babies, if the parents choose to go ahead with the pregnancy, they warn.

The researchers compare the current situation with thalidomide, which resulted in the births of 500 people with disabilities in the UK.

“Justifiably, steps were introduced to immediately halt the epidemic, and regulatory precautions were introduced to avoid another similar epidemic,” they write. “Unfortunately, no such sense of urgency has been applied to the prevention of spina bifida,” the authors say.

“It is a public health failure that Britain has not implemented the fortification of flour with folic acid for the prevention of spina bifida and other [neural tube defects],” they write. This failure “has caused, and continues to cause, avoidable terminations of pregnancy, stillbirths, neonatal deaths and permanent serious disability in surviving children,” they conclude.


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