The somewhat misleadingly named folic acid is in fact one
of the most important of the water soluble B complex of
vitamins. In the form of folates it is found naturally in
the body as well as in various common foods. As folic acid
it has been extensively researched and is widely available
as a food supplement.
Inadequate dietary intake of folates by pregnant women has
been widely publicised as a cause of serious and even fatal
birth defects. Research has also suggested a strong
association between folate deficiency and an increased
incidence of certain of the more common cancers.
The implications of these findings will be covered in
subsequent articles in this series, but this article will
focus on the role of folates and folic acid in regulating
blood homocysteine, excessively high levels of which have
been identified as a key risk factor for both
cardiovascular disease and Alzheimer's disease.
Homocysteine is a protein formed as a perfectly normal
by-product of the body's digestive processes and in
optimally healthy individuals it will be removed harmlessly
from the body But its effective removal is heavily
dependent on the presence of adequate supplies of three B
complex vitamins, B6, B12 and folic acid or folates.
The build up of excess homocysteine if these vitamins are
not present in sufficient quantities can have severe
consequences. A large 1997 European study of young and
middle aged adults showed a more than doubled risk of
cardiovascular disease and stroke for individuals whose
blood homocysteine levels were in the top fifth of the
normal range. In fact some sources attribute as many as
10% of heart attack fatalities and an even higher
proportion of stroke deaths directly to high homocysteine
levels. Since these are still two of the biggest causes of
premature death and disability in the affluent Western
world, such figures are particularly alarming.
The link between raised homocysteine levels and Alzheimer's
disease is not quite so well established, at least in the
view of orthodox medicine, but a number of studies have
found a clear association. It has also been observed that
sufferers from this appalling disease are more likely to be
deficient in both folic acid and dietary folates. Not
surprisingly perhaps, given that damage to blood vessels
appears to be one of the principal effects of elevated
homocysteine, it has also been strongly linked with
vascular dementia.
The role of folic acid and folates in lowering blood
homcysteine levels is well established, with one recent
study showing 60% and 90% reductions when supplement
regimes of 0.2 mg and 0.4 mg respectively were followed.
And given that high homocysteine levels have been shown to
increase the risk of cardiovascular disease, as well as
Alzheimer's and other dementias, it might be thought
self-evident that supplementation should be a powerful
weapon against them.
Conventional medicine, however, continues to be cautious
about recognising the link. Although there is good
evidence from at least one ten year study that high levels
of dietary folate can reduce heart attack risk by more than
50%, there appears not be the same direct corroboration for
the effects of folic acid supplementation. Somewhat
bizarrely, therefore, the profession finds itself
recommending supplementation for the purpose of reducing
the elevated homocysteine levels known to increase the risk
of disease, but declines to recommend it as a specific
protector against the disease itself. Not surprisingly,
nutritional therapists show no such hesitation, and many
recommend supplementation at levels far in excess of the
officially Recommended Dietary Allowance (RDA) of 400 mcg
(0.4 mg) a day.
But whatever the benefits of high dosage supplementation,
it is clear in any case that a diet rich in folates can
only be of benefit to the body's general health. This is
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.
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.
Despite this official recognition of the importance of this
nutrient, the US Food and Nutrition Board nevertheless
recommends that folic acid intake should be limited to
1,000 mcg (1 mg) per day. But this is not so much because
of any possible ill effects of the folic acid itself, but
rather because it may cure megaloblastic (commonly known as
pernicious) anaemia which is one of the symptoms of an
underlying deficiency of vitamin B12. If the removal of
this symptom means that the deficiency is consequently
undetected and left untreated, the neurological
consequences may indeed be severe.
But to the educated layman the solution to this potential
problem appears readily apparent. It is simply to ensure,
through supplementation if necessary, that a generous
intake of vitamin B12 is also obtained. This should
present no difficulty if the standard recommendation never
to take one of the B vitamins in isolation is followed.
These vitamins should always be taken as part of a
supplement containing the entire complex, and for maximum
benefit should preferably be accompanied by a comprehensive
multi-mineral.
----------------------------------------------------
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
No comments:
Post a Comment