Download Folic acid and the prevention of NTDs

H E A LT H
Folic acid and the prevention
of NTDs
Adequate levels of folic acid in the mother’s body at conception and in the early stages of pregnancy can
prevent serious birth defects, such as spina bifida. But pregnancy can be a surprise. This makes getting
the message to those most at risk a real challenge.
The National Committee on Folic Acid
Food Fortification was established in
2004. The Committee is looking at the
issue of fortifying foods with folic acid
in light of the relatively high levels of
neural tube defects (NTDs) in Ireland
of data on pregnancies that do not
reach full term and the lack of a
national congenital defects birth
register in Ireland.
NTDs are a group of birth defects
that result in abnormalities in the
Genetics.
and evidence that folic acid
consumption can reduce the incidence
of these birth defects. The Committee
report, published in 2006, highlighted
that the incidence of NTDs in Ireland
is higher than in the rest of Europe. In
2004, it was estimated that 1.5 in every
1000 babies are born with an NTD
each year. The report also noted the
central nervous system and spinal cord.
These occur in the first few weeks of
pregnancy. The most common NTD is
spina bifida. The spinal defect can
sometimes be repaired through surgery,
but surgery is not always a solution.
Most babies born with spina bifida will
survive but will have moderate to
severe handicap. More severe NTDs,
Early pregnancy.
actual incidence of NTDs may be
under-estimated because of the absence
such as anencephaly and iniencephaly,
are fatal.
AT A GLANCE
NTDs.
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JULY 2008 HEALTH
Folate and folic acid
The B vitamin, folate, occurs naturally
in foods. Good natural dietary sources
of folate include: green vegetables,
especially asparagus, broccoli, green
beans, peas and spinach. Other good
sources include: cauliflower, eggs,
potatoes, oranges and orange juice. But
as with many vitamins, folate is easily
destroyed during cooking, food
processing and even if fruit or
vegetables are over-ripe or bruised.
Folic acid, the synthetic form of folate,
is most commonly used in vitamin
supplements and fortified foods. See
our tables for the folic acid content of a
range of vitamin supplements and a
variation within certain genes can also
influence how well folate is used in
the body.
Down to the genes
It has been found that a section of the
Irish population have a genetic
predisposition to metabolise folate
differently. Research based in Ireland
has identified variations in at least two
genes that can increase the risk of
having a baby with an NTD. This leaves
some individuals with a greater risk due
to their genetic makeup. Up to half of
folate related NTDs are thought to be
explained by one of these genes, known
as MTHFR. A 2004 paper published in
the British Medical Journal showed that
the link between MTHFR genotype and
NTD risk was greater than previously
thought. This means that some women
need more folic acid than others, not
these birth defects. But this may prove
to be another challenge.
Useful contacts
Food Safety
Who needs folic acid?
Authority of Ireland
It has been found that there is a high level
of public awareness of the importance of
taking folic acid during pregnancy. The
advice is that folic acid supplements at a
level of 400µg should be taken prior to
conception and for the first twelve weeks
Abbey Court
of pregnancy. However, being aware of
this fact does not always mean it is acted
upon. Also, the time when folic acid is
taken is crucial to prevent NTDs. When
pregnancies are planned and folic acid is
taken, this most often starts when the
pregnancy is confirmed. This is too late as
the neural tube is completely developed
between 21 and 28 days after conception.
Research from the UK published in
Public Health Nutrition found that a
large proportion of women reported
www.fsai.ie
Lower Abbey Street
Dublin 1
Advice 1890 336 677
tel (01) 817 1300
fax (01) 817 1301
email [email protected]
The Irish
Association for
Spina Bifida and
Hydrocephalus
National Resource
Centre
Old Nangor Road
Clondalkin
Dublin 22
1890 20 22 60
tel (01) 457 2329
fax (01) 457 2328
“When only a specific group of the
population has higher folic acid needs, we
must ask whether mandatory fortification of
bread is the right approach.”
www.iasbah.ie
Irish Nutrition and
Dietetic Association
Ashgrove House
Kill Avenue
Dun Laoghaire
Co. Dublin
email [email protected]
www.indi.ie
selection of fortified foods. You may
also see a blue symbol on some foods
stating ‘with extra folic acid’ or ‘contains
just because natural dietary sources of
folate may be less effectively absorbed
than synthetic folic acid, but because of
folic acid’. This symbol has been devised
by the Food Safety Authority of Ireland
(FSAI, see Useful contacts) to indicate
that food has been fortified.
Research has shown that folic acid is
better absorbed by the body than
natural folate. This can also be referred
to as ‘bioavailability’. Foods that have
natural folate can contain inhibitors
that block the absorption of the
vitamin. Folic acid, the synthetic form
of folate, is not easily destroyed or
this genetic predisposition.
For most adults, the Recommended
Daily Allowance (RDA) of folate is 200
micrograms (µg) per day. However, for
women of childbearing age, an intake of
400µg of folic acid per day is
recommended to protect their
pregnancy against the development of
NTDs. However, the Irish Association
for Spina Bifida and Hydrocephalus
(see Useful contacts) recommends that
women with a higher risk of having a
affected by inhibitors. This means the
body can then make better use of the
vitamin in the synthetic form.
However, natural food sources of
folate still make a vital contribution to
our daily intake. Research published
last year in the American Journal of
Clinical Nutrition found that the
baby with an NTD need to take as
much as 4000µg per day, ten times the
recommended amount for women of
childbearing age. Family history of the
presence of NTDs is one sign of those
who are at risk.
For women in the higher risk
category, eating foods naturally high in
bioavailability of the natural folates
can be as high as 80% of that of folic
acid. Foods naturally high in folate are
also good sources of other valuable
vitamins and fibre.
Besides folate bioavailability,
folate or food fortified with folic acid
will not provide the required amount of
folate to protect against having a baby
with an NTD. Those in the high risk
category should be identified and
targeted to help reduce the incidence of
taking folic acid during pregnancy.
However, more significantly, most did
not take it in early pregnancy when it is
most needed to protect against NTDs. It
was also found that those from lower
socio-economic groups were much less
likely to take folic acid when it is most
critical. Younger women were less likely
to take folic acid at all. This evidence is
also reflected in Ireland’s population.
Research carried out in Ireland from
2001-3 found that folic acid is often not
taken before conception. It was also
found that younger, poorer and less
educated women were the least likely to
take folic acid.
Useful websites
European Food
Information Council
www.eufic.org
Folic acid, today
and everyday
www.folicacid.ie
Catch 22?
Planning for the unplanned
The Committee report highlights that
about half of all pregnancies in Ireland
are unplanned. There is an inherent
contradiction here that makes it more
difficult to address the need for women
to take folic acid before they conceive.
Folic acid is needed at adequate levels in
the early stages of pregnancy to help
prevent NTDs. But if women are not
planning on having a baby, with the
HEALTH JULY 2008
consumer choice
Report by
Aisling Murtagh cc
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FOLIC ACID CONTENT
Folic acid per dose (µg)
Supplement
B VITAMINS
Berocca Plus effervescent
366
Solgar B complex ‘50’ tablets
400
Sona B complex tablets
400
Quest Multi B complex
400
Viridian B complex High Five capsules
200
FOLIC ACID SUPPLEMENTS
general pressures and worries of life, it
is unlikely they will prioritise one issue
and one nutrient. Women who are not
planning pregnancy are more likely to
use contraception, such as the pill.
Would adding folic acid to the
contraceptive pill go some short way to
lessening the risk? Such a move may be
controversial in itself. Or is there
another solution?
Clonfolic folic acid tablets
400
Sona folic acid tablets
400
Food fortification
Viridian folic acid capsules
400
The issues are clear, but the solutions are
not. However, in 2006 the National
Committee on Folic Acid Food
Fortification recommended that most
white, brown and wholemeal bread on
sale in Ireland should be fortified with
120µg of folic acid per 100g. The aim is to
increase folic acid intake in all women of
IRON SUPPLEMENTS
Sona iron complete liquid
100
Vitabiotics Feroglobin capsules
500
MULTIVITAMINS
Centrum Complete tablets
200
Seven Seas Multibionta tablets
200
Solgar VM-75 tablets
400
Sona Multiplus capsules
400
Quest Super Once a Day tablets
200
Sona Calcium Complete tablets
200
Vitabiotics Skin, Hair and Nails capsules
500
childbearing age. It was also recommended
that monitoring is an essential part of a
fortification programme, to ensure it is
effective and safe.
Mandatory folic acid fortification of
foods has already been introduced in
other countries, such as the US,
Canada, Chile, Brazil, Indonesia and
Israel. In the case of the US, it has
been documented that this has led to
Alpro light unsweetened soya milk
85 per 250ml
a decline in the incidence of NTDs.
Research from 2002 found that the
increase in folic acid in the
Avonmore Supermilk
70 per 100ml
Brennans sliced white bread
19 per slice
Dairygold light
100 per 10g serving
Flora vegetable spread
100 per 10g serving
Kelloggs breakfast cereals1
58 per 30g serving
Kelloggs Nutrigrain bar
50 per bar
SUPPLEMENTS FOR PREGNANCY
Vitabiotics Pregnacare tablets
400
Viridian Pregnancy Complex capsules
400
SUPPLEMENTS FOR WOMEN
Solgar Female Multiple tablets
800
Vitabiotics Wellwoman capsules
400
OTHER SUPPLEMENTS
Pharmaton capsules
100
FORTIFIED FOODS: FOLIC ACID CONTENT
Kelloggs Special K cereal bar2
34 per bar
Nestle breakfast cereals1
51 per 30g serving
1 Folic acid content may vary slightly depending on cereal and serving size. 2 Kelloggs
cereal bars in general are fortified, folic acid content may vary depending on size of bar.
population was double than expected.
However, all flour in the US is
fortified with folic acid at the level of
140µg per 100g of grain.
But regardless, this creates another
question that needs addressing: what
are the implications of fortifying bread
with folic acid for those outside of the
target category? There are reported risks
and benefits beyond NTD prevention.
choice comment
Mandatory folic acid fortification of foods has great potential benefit. However, the time and circumstance in life
when we consume more or less folic acid has an impact on whether it is beneficial. A high intake is not best for the
elderly and those with polyps in the bowel, which are more common in the over 50s. On the other hand, it is
essential to ensure women of childbearing age get enough folic acid to prevent NTDs. The key point seems that
most women know they should take folic acid, but also need to become aware of when it is most important.
It is vital to have enough folic acid in the body pre-conception and in the early stages of pregnancy. When only a
specific group of the population has higher folic acid needs, we must ask whether mandatory fortification of bread is
the right approach. This could also increase the folic acid intake of those who don’t need it.
To retain consumer choice, it is proposed that only some breads will be fortified. Is this enough to allow
consumers to make informed choices? Consumers must be made aware of which foods contain added folic acid,
especially since extra folic acid is not good for some consumers and they may not be aware of this.
This issue goes beyond mandatory fortification. Many foods and food supplements already contain folic acid at
varying levels. It also raises another issue - the need for greater regulation of voluntary fortification of foods with all
nutrients - not just folic acid.
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Benefits
There are general nutritional benefits
from having an adequate intake of folic
acid. It supports the nervous system and
general cell function. The genetic
predisposition discussed earlier does not
just relate to NTDs, but has also been
found to contribute to a greater risk of
developing other diseases, such as
cancer, heart and Alzheimer’s disease,
because of the inadequate use of folate
in the body.
Risks
Increased intake of folic acid in the
elderly has been found to mask vitamin
B12 deficiency. This can then enhance
the deterioration of nervous system
functioning that result from B12
deficiency, if undiagnosed. Questions
have also been raised regarding the
potential effects of stores of unused folic
acid in the liver.
Research has also suggested that
taking folic acid supplements can
increase the risk of bowel cancer in at
risk populations, such as those who
have polyps in the colon. These are
more common in the over 50s. While
most polyps will not develop into
cancer, high levels of folic acid can
accelerate the process where cells may
become cancerous. This is worrying
when we look at the fact that bowel
cancer is the second most common
cancer in Ireland (skin cancer being the
most common).
Mandatory fortification of folic acid
has also been proposed in the UK. The
issue is currently on hold pending an
expert review of evidence relating to
bowel cancer risk and folic acid. This
review is not expected to be concluded
until mid-2009.
It is important to highlight that
when the link between bowel cancer
risk and folic acid has been made, high
levels of folic acid were consumed, well
above the RDA.
In Ireland, recommendations from
the mandatory fortification programme
have set an upper limit on the amount
of folic acid to be added to bread
(120µg per 100g). This aims to provide
protection against a high intake
occurring in the general population.
Folic acid is a vitamin we all need.
We must keep in mind that there is a
distinction between the benefits of folic
acid at recommended levels, and the
potential risks of a high intake.