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Special report on folic acid fortification

10th March 2007

Author: Yvonne Wake, Public Health Nutritionist and Associate Lecturer at Roehampton University, London.

The 2000 Committee on the Medical Aspects of Food and Nutrition (COMA) report on Folic Acid and the Prevention of Disease has been updated by The Scientific Advisory Committee on Nutrition (SACN) with a list of recommendations relating to folic acid fortification in the UK which is principally designed for women of childbearing age and pregnant women.

COMA made its recommendations in 2000 following a review of all available evidence linking folic acid with human health, and in particular the need for adequate intakes of folate at the time of conception to reduce the risk of a pregnancy affected by neural tube defect (NTD).

The COMA report concluded that fortification of flour with folic acid would be the best way to reduce the amount of pregnancies affected by NTD, but this was refuted by the Food Standards Agency due to concerns about the impact on older adults (65+) with vitamin B12 deficiency who might be misdiagnosed as a result of the masking effect of folate on B12 deficiency. There were also concerns over consumer choice.

However, following a request from the Minister for Health in 2004 to consider folic acid fortification, the debate is ongoing. According to SACN, old evidence has been reassessed and new evidence has emerged showing large benefits of folic acid supplementation in reducing the risk of pregnancies affected by NTD.

This evidence is also supported by the results of mandatory fortification of flour in the USA, Canada and Chile where there is between 27% to 50% reduction in NTD related pregnancies. Available data on NTD-affected pregnancies in the UK appears to be 'insecure' (SACN) because there is so much under-reporting, but figures for 2003 were seen at between 700-900 single births. This leads to obvious questions about why these women are not getting enough folate in their diets and why is it so difficult to target women of childbearing age?

The RNI in the UK for folate is 200 g per day and the tolerable upper level (UL) is 1mg/day, however it is recommended for all women of childbearing age who intend to conceive a child to take a 400g/day supplement of folic acid prior to conception and until the twelfth week of pregnancy in order to prevent NTD.

Data from the National Diet and Nutrition Survey (NDNS) showed that although average daily folate intakes were above the RNI in all age groups, there was some evidence of marginal folate status in young women and people aged >65 years, although SACN supports the fact that it really is very difficult to accurately assess these findings.

Folate (B-group vitamins) is found in a variety of foods such as liver, spinach, green leafy vegetables, and is especially rich in Kale and Brussels sprouts. Which are not exactly the favourite foods of the young and older age groups seen to be consuming 'marginal' folate.

According to Andrew Whitley, author of Bread Matters, (and the originator in 1976 of the Village Bakery in Melmerby) Britons consume around eight million loaves of bread a day plus other countless bread type food such as rolls and croissants. He explained to me that millers remove folate from flour at the time when whole wheat is roller milled to white flour. Half the folate in whole wheat is lost in the milling to white flour. So the message here is pretty obviously 'eat more wholemeal bread' if you want to increase folate consumption.

Whitley reminds us that although almost all age and social groups in the UK consume less than the recommended amount of fibre (16 grams a day); public health messages are not telling us this with the same given emphasis as the salt, fat and sugar messages. Although people are embarrassed to admit it, there appears to be as many as 14 million people in the UK suffering from constipation and 30% of them are children. He objects to mandatory fortification of flour with folic acid because it is a crude form of mass medication which uses a laudable aim (i.e. NTD) but a flawed method.

He says that mandatory fortification is an admission of defeat, implying that there is no other way to get women of child-bearing age to consume enough folate other than sneaking it into all the flour they eat. Also, by not encouraging these women directly to consume an appropriate diet (with supplements if necessary), the policy runs completely counter to the 'choice' and 'personalisation' agendas set out by the government in its 2005 'Choosing Health' white paper. He thinks there is a case for insisting that all flour should have a baseline of adequate nutrients, but this should be done by leaving in more of what is already there (in the whole grain) rather than adding back selective nutrients.

The folate story is a complicated one however and it's not just a question of folate intakes. There is also concern over vitamin B12 deficiency in the elderly and studies have also shown that the dose and the timing of these two vitamin B intakes are crucial to health. In order to shed some light on this very complex subject, Morris et al (2007) examined 1500 healthy elderly persons aged >60 years, and found that high serum folate was associated with anaemia and cognitive impairment in seniors with low vitamin B12 status, and when B12 status was normal, high serum folate was associated with protection against cognitive impairment.

So basically, if your B12 status is good, folate supplementation was good for you, however, cognitive impairment and anaemia usually associated with low vitamin B12 status are made much worse by a high folate status. They found that ~1.8 million elderly might be at increased risk of cognitive impairment and anaemia because of an imbalance between folate and vitamin B12. Thus, this large number of elderly at increased risk of cognitive impairment and anaemia has to be balanced against the number of infants in whom NTDs are being prevented.

David Smith is Professor of Pharmacology at the University of Oxford. The question on his mind is, 'is it ethical to save one infant from developing NTD and hopefully provide that child a high quality life but increase the risk of poorer health in >1000 elderly persons'? On folic acid fortification, Smith asks, 'should countries considering folic acid fortification defer a decision until more is known about the interaction between folate and B12 status?

Smith may be right, as SACN have only made recommendations at this stage and the report openly admits that there is still uncertainty over whether or not folic acid should be the next fortification program in the UK. To confound and add to the uncertainty, food manufacturers are allowed to add folic acid to many types of foods as there are no official controls. Individuals may also choose to take supplements for folic acid.

So in actual fact it is not really known exactly how much folic acid the UK population is consuming and SACN accept that if mandatory fortification of flour was to occur at current levels of folic acid intake (to include intakes from voluntary fortification and supplements) it would also increase the proportion of people in the population at risk of exceeding folic acid intakes above the upper level of 1mg/day and the number of people aged >65 years with low vitamin B12 status would be at risk.

As a result of this, SACN recommends that mandatory fortification should only be introduced in the UK if it is in association with:

  • Action to reduce folic acid intakes from voluntary fortified foods to ensure that the numbers of people with intakes above the GL/UL per day do not exceed current levels and there is no substantial increase in mean intakes or in the folate status of the UK population;
  • Measures for careful monitoring of emerging evidence on the effects of long-term exposure to intakes of folic acid above the GL/UL per day and postulated adverse effects including neurological damage, CVD and cancer.

SACN have also stated that if fortification were to take place; careful consideration will be given to the excess intakes of folic acid within the population, that evidence on benefits of fortification be shown after a five year period, that the general population be given clear guidance on folic acid supplements, and that more reliable diagnoses to identify vitamin B12 deficiency and a clinical strategy to manage issues related to B12 deficiency.

The issues surrounding folate have always been unconvincing which is probably because NO studies have been carried out in non-childbearing subsets of the population to see whether they might also benefit from, or be harmed by exposure to folic acid. The established view was that it must be 'a good thing' to give extra folic acid, not only to prevent NTD's but perhaps prevent cardiovascular disease because it is thought to lower plasma homocysteine concentrations.

Yes, folic acid fortification has reduced the number of NTD's in the USA, which can only be good, but by the same token, there is no conclusive evidence that a folic acid intervention aids cardiovascular disease. If anything, recent findings have resulted in cause for concern (David Smith, 2007),

In the case of cancer where folate nutrition has been more recently associated as a cancer preventative agent, there are differing opinions that folate deficiency enhances, whereas folate supplementation reduces the risk of colorectal cancer (CRC). Kim (2006) argues that recent animal studies and interventions have dampened the enthusiasm for the potential role of folate supplement in CRC prevention and although several animal studies have suggested harmful effects of high folate status, these studies have been ignored by public health policy makers.

Folate appears to possess duel modulatory effects on CRC depending on the timing and dose of folate intervention. An emerging body of evidence suggests that folate may possess potentially serious adverse effects, and not just the masking of B12 deficiency in the elderly.

Supporters of mandatory folic acid have branded the hesitance in folic acid fortification in European countries as public health malpractice, however, if we look at the current debate it appears that this inactivity is better regarded as public health prudence. Mandatory folic acid fortification is a very important consideration and regardless of its benefits in preventing NTD's in other parts of the world, the possibility still remains that certain sections of the exposed population could possibly experience some very distressing adverse effects from increased folic acid intake.

The Food Standards Agency (FSA) have launched a consultation setting out potential options to improve the intake of folate for young women with a view to reducing the amount of neural tube defect (NTD) affected pregnancies in the UK. This is the website to offer your opinions http://www.food.gov.uk/folicacid, and the four suggested options are:

  • to continue the current policy of advising all women who are planning a pregnancy to take a 400 mg folic acid supplement daily, before conception and up until the 12th week of pregnancy;
  • To increase efforts to encourage young women to take folic acid supplements as well as increasing their consumption of folate-rich foods;
  • To encourage the food industry to fortify more foods with folic acid on a voluntary basis;
  • To recommend the mandatory fortification of bread or flour with folic acid.

The 13th March 2007 is the deadline for responses. The FSA board meeting will be held in May 2007 to discuss the SACN report on Folate and Disease Prevention and the consultation feedback. According to Rosemary Hignett who is head of Nutrition at FSA 'this is an opportunity for consumers, industry, health charities and other stakeholders to express their views and opinions on this issue'.

The incidence of Neural Tube Defect is the driving force behind folate fortification. Surely we should be concentrating on finding ways of encouraging women of childbearing age and pregnant women to increase their intakes through good healthy food?

References:

Kim Y-I (2006) Folate: a magic bullet or a double edged sword for colorectal cancer prevention. Gut, 55: 1387-1389
Morris M S., Jacques P F., Rosenberg I H., & Selhub J (2007), Folate and vitamin B12 status in relation to anaemia, macrocytosis, and cognitive impairment in older Americans in the ago of folic acid fortification. American Journal of Clinical Nutrition 85; 193-200
Rosenberg I.H. (2005) Science-based micronutrient fortification: which nutrients, how much, and how to know? American Journal of Clinical Nutrition 82; 279-80.
SACN (2006) Folate and Disease Prevention. London TSO
Smith D., (2007) Folic Acid fortification: the good, the bad, and the puzzle of vitamin B-12. American Journal of Clinical Nutrition; 85 3 - 5
Whitley A (2006) Bread Matters - The state of modern bread and definitive guide to baking your own. Fourth Estate, London