Folic
Acid
DESCRIPTION:
Folic acid was originally found in
yeast, where it was recognised to be an "anti-Anaemia"
factor. Folic acid is a member of the B complex and has the
chemical name pteroyl glutamic acid.
Folic acid is unstable to heat, air,
water and alkali, and careful cooking methods must be employed
to ensure adequate amounts of this vitamin are retained.
Folic acid is needed for many
physiological reactions. More specifically, folic acid is needed
for the synthesis of DNA and therefore for cell division. It is
also involved in the production of the non-essential Amino
Acids methionine and glycine.
DEFICIENCY
Folic acid deficiency causes a
megaloblastic Anaemia
(see vitamin B12).
This is often also associated with a diminished number of white
blood cells (leucopenia).
Rapidly generating tissues are
affected by folic acid deficiency and so the intestinal mucosa
may also suffer. In babies and young children, growth may be
affected.
Those who are most at risk from
folic acid deficiency are as follows:
- The elderly (who tend to have
poorer diets or impaired absorption)
- Those with intestinal
malabsorption syndromes (particularly steatorrhoea, where
the stools contain undigested fat)
- Pregnant women (the developing
foetus make considerable demands on the maternal folic acid
stores)
- Alcoholics
Upper safe level for daily
supplementation = 400µg
Recommended Daily Allowance = 200µg
Birth Defects:
Supplements of folic acid (400 µg per day) are highly advisable
prior to conception as well as in the first twelve weeks of Pregnancy,
as low folic acid intake is strongly associated with the birth
defect spina bifida (1).
Anaemia:
Folic acid supplements must be used under medical supervision
for the treatment of diagnosed megaloblastic Anaemia,
as folic acid can mask a vitamin B12 deficiency (2) (see under
vitamin B12 section). Normally, folic acid is only prescribed
after vitamin B12 has already failed to bring a response.
Alcoholics:
Alcoholics may benefit from a supplement of folic acid as they
tend to have depleted levels of this vitamin (3).
Coronary Heart Disease:
Recent research shows that folic acid supplements may offer
protection against heart problems in later life by maintaining
low blood homocysteine levels (4).
The overall risk from folic acid
mega-dosing is deemed very slight.
INTERACTIONS
AND CONTRA-INDICATIONS
Vitamin B12:
As previously mentioned, folic acid supplements taken by people
with developing vitamin B12 deficiency may obscure a correct
diagnosis and delay the appropriate treatment.
Zinc:
Very high folic acid intakes may also result in disturbed Zinc
absorption.
Methotrexate:
Certain drugs used in the treatment of cancer (e.g. methotrexate)
are specifically designed to inhibit folic acid. People being
given these drugs should therefore only take folic acid
containing supplements under strict medical supervision.
Anticonvulsant Drugs:
Folic acid should not be taken with anti-convulsant drugs unless
directed by a medical doctor.
Food (µg/100g)
Brewer’s yeast 2400
Wheatgerm
310
Wheat bran 260
Nuts 110
Pig’s liver 110
Leafy green vegetables 90
Bread, wholemeal 39
Eggs 30
Bread, white 27
Fish, fatty 26
Bananas 22
Potatoes 14
REFERENCES:
1. Butterworth CE Jr and Bendich A.
Folic acid and the prevention of birth defects. Annu Rev Nutr,
16:73-97, 1996.
2. Matthews JH. Cobalamin
and folate deficiency in the elderly. Baillieres Clin Haematol,
8;3:679-697, 1995.
3. Cravo ML et al. Hyperhomocysteinemia
in chronic Alcoholism:
correlation with folate, vitamin B12
and vitamin B6
status. Am J Clin Nutr, 63;2:220-224, 1996.
4. Lowering blood homocysteine with folic acid based
supplements: meta-analysis of randomised trials, 316:894-8,
1998.
Related News Stories
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on emotional health.
Research into the amounts of folic
acid needed by pregnant and breastfeeding women.
Recommended levels of folic acid
during pregnancy.
Researched links between B vitamins
and hearing loss in the elderly.
Adequate folic acid intakes may help
prevent homocysteine.
Studies support the use of a
multivitamin supplement in reducing the risk of colon cancer.
Ensuring good levels of zinc during
pregnancy and whilst breast-feeding will increase the baby's
chances of being healthy.
Research into foetal abnormalities
and folate supplementation in developing countries.
B vitamins help to lower
homocysteine levels, which may help prevent the risk of heart
disease.
Research suggests that low levels of
folic acid may increase the risk of heart disease.
Folic acid is needed for many
physiological reactions, especially for the synthesis of DNA and
therefore for cell division. During pregnancy the developing
foetus makes considerable demands on the maternal f
olic acid stores, therefore it is important for pregnant women
to have adequate stores of f
olic acid.
Research into folic acid gives
greater understanding of its role in the body.
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