Inadequate intake of dietary folates and folic acid has
been strongly associated with the elevated levels of blood
homocysteine which have been identified as a key risk
factor for both cardiovascular disease and Alzheimer's
disease. But folates and folic acid are also very
important in protecting against certain cancers and birth
defects and it is these functions which are considered here.
The term folic acid may be confusing to some, because it is
in fact one of the most important and heavily researched of
the B complex of vitamins and widely used in this form as a
dietary supplement. In the form of folate compounds the
vitamin is also found naturally in the body as well as in
various common foods.
Folic acid is essential for a large number of biochemical
reactions within the body, including the metabolism of
energy from food, but is particularly important in ensuring
that the continual process of cell division within the body
proceeds normally. This is especially vital during the
rapid development and production of new cells during the
first weeks after conception. Inadequate intake of folates
and/or folic acid in the early stages of pregnancy has been
identified as a cause of what are known as "neural tube
defects" which lead to inadequate or abnormal development
of the foetal brain and spinal cord.
One of the most dreaded diseases which may result from
these problems is spina bifida, but the incidence of this
has been shown to be reduced by 75% when folic acid
supplements of 400 mcg are taken during the first three
months of pregnancy. Folic acid supplements are
recommended because they are much more easily absorbed,
"bioavailable" in the jargon, than folates from food.
It would in fact be difficult to obtain sufficient supplies
of this nutrient from ordinary food sources.
Supplementation is therefore recommended for all women of
child bearing age because the need for this nutrient is at
its most critical in the very early days of a pregnancy,
possibly before the mother is even aware of her condition.
This is not to say, however, that a diet rich in folates
should not still be followed, because amongst the best and
most readily available sources of folates are leafy green
vegetables, and orange juice which also provide a plentiful
supply of valuable anti-oxidants and are extremely
beneficial to general health.
A single cup of spinach or asparagus, for example, may
provide as much as 130 or more micrograms (mcg) of folate;
a small glass of orange juice perhaps 80 mcg. Pulses such
as beans and lentils are also good sources, the latter
providing around 180 mcg in just half a cup, beans between
80 and 140 mcg according to type.
Best of all, however, is fortified breakfast cereal, a
single cup of which may yield between 200 and 400 mcg,
reflecting the FDA's insistence on the addition of folic
acid to refined grain foods, including bread.
Although this policy is driven mostly by a desire to
protect the unborn, the more general advice to consume at
least five servings of fruit and vegetables a day has also
been put forward as a protector against cancer. Certainly
such a diet would be rich in folates, and research suggests
a strong association between folate deficiency and an
increased incidence of certain of the more common cancers,
including those of the cervix, colon and rectum, lung,
oesophagus and breast. It is thought that the association
may arise because of the role of folate in DNA repair
within cells, DNA damage being regarded as a principal
cause of cancer.
However, conventional medicine remains reluctant to accept
folic acid supplementation as a possible weapon in the
battle against cancer, even though one large scale study
has reported a halving of breast cancer risk in women
taking more than 600 mcg daily. For reasons which are not
understood, however, this protective effect was only
observed in the case of those women who also consumed at
least one alcoholic drink per day. In general it can be
said that the link between folic acid intake and cancer
risk remains a matter of association rather than clear
causation, but orthodox opinion is much less cautious in
recommending a high intake of folates from food.
But not surprisingly, given the potential benefits,
nutritional therapists are much less a cautious in
recommending folic acid supplementation at levels far in
excess of the officially Recommended Dietary Allowance
(RDA) of 400 mcg (0.4 mg) a day; some suggesting as much as
10 mg (10,000 mcg). And in fact there appears little
reason for concern over the ingestion of such apparently
large amounts.
Although the US Food and Nutrition Board has recommended
that folic acid intake should be limited to 1,000 mcg (1
mg) per day, this is not so much because of possible
problems with such an intake of folic acid in itself, but
rather because it may cure a particular type of anaemia
which is one of the symptoms of an underlying deficiency of
vitamin B12. Whilst you might think that such a cure would
be beneficial, the problem is that it may mask the
underlying vitamin B12 deficiency with potentially serious
neurological consequences.
But the solution to the problem would seem straightforward.
It is simply to ensure that a generous supply of vitamin
B12 is obtained along with any folic acid taken. And this
should not be difficult if the vitamins are taken as part
of a supplement containing the entire B complex, as is
always recommended. As with all vitamins supplements, they
should for maximum effectiveness be taken in conjunction
with a comprehensive multi-mineral.
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Steve Smith is a freelance copywriter specialising in
direct marketing and with a particular interest in health
products.
Find out more at
http://www.sisyphuspublicationsonline.com/LiquidNutrition/In
formation.htm
