This week saw the publication of the updated recommendations of the Scientific Advisory Committee on Nutrition (SACN) of mandatory fortification of flour with folic acid, which supports its previous recommendations to the UK government. If this is implemented it would mean that staple products, such as bread, would be likely to make a larger contribution to the folic acid intake of the population.
Why have SACN made this recommendation?
Conclusive evidence has shown that folic acid supplementation during the early stages of pregnancy can reduce the risk of the foetus developing neural tube defects (NTDs) like spina bifida. Currently though, although all UK women of childbearing age are advised to take a daily supplement of folic acid prior to conception and until the 12th week of pregnancy, evidence suggests that this recommendation is not being widely followed.
Significant reductions in the prevalence of NTDs have been reported in countries where mandatory folic acid fortification policies have been reduced, and this would, therefore, seem an effective way to reduce the risk of NTDs.
But could there be any potential adverse effects of folic acid fortification to older people in care homes?
A concern that has been previously raised is that high intakes of folic acid from fortified foods and dietary supplements might mask the anaemia of vitamin B12 deficiency.
In older people the ability to absorb vitamin B12 can decrease, so the elderly are particularly at risk of vitamin B12 deficiency. Symptoms associated with vitamin B12 deficiency include anaemia (identical to that of folate deficiency) and nerve and psychological problems including depression, difficulty with memory, numbness, pins and needles, vision changes and unsteadiness. Treatment with folic acid can improve the anaemia, which could delay a diagnosis of vitamin B12 deficiency, and may lead to irreversible neurological damage. It is therefore important that a timely diagnosis can be made.
Mandatory fortification of folic acid in the US for the last 20 years does not indicate a cause for concern in older people.
SACN reported that no systematic reviews (the type of study that would be used for robust evidence) have evaluated the risk of folic acid masking or exacerbating vitamin B12 deficiency in adults. Where evidence exists in relation to folic acid intakes impacting on vitamin B12 deficiency, such evidence indicates that this relates to doses in excess of 1mg/d. We know from dietary surveys that even amongst the highest consumers of folic acid, intakes are far below that, and it is unlikely that contributions from fortification would lead to intakes exceeding 1mg/day of folic acid. In addition, whilst the risk of NTDs decreased after mandatory fortification in the US (introduced in 1998), the prevalence of vitamin B12 deficiency with or without anaemia has not increased.
SACN also looked at folic acid and cancer risk. Scientific findings are inconsistent but overall do not suggest an adverse effect.
So SACN has recommended mandatory fortification of flour with folic acid, but they have also stressed that this should only be introduced accompanied by controls on voluntary fortification, guidance on supplement use and appropriate population monitoring. This is to ensure mandatory folic acid fortification does not lead to an increase in the proportion of the population with folic acid intakes above 1mg/day.
