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Protect
Against Cancer With Folic Acid
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 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.
Steve Smith
