Although dietary zinc has been known since the 1960s to
play an important role in human health, it was not until as
recently as 1990 that its role as an important ant-oxidant
was identified. Perhaps not surprisingly, early attention
focussed on zinc's role as an essential mineral for sexual
and reproductive health, particularly in the male; but it
is now known that its functions are much more numerous.
Indeed some nutritional practitioners go so far as to claim
that plentiful supplies of dietary zinc are vital for the
proper functioning of every cell in the body.
Initial laboratory experiments appeared to show two ways in
which zinc discharged its anti-oxidant functions. The first
is that dozens of vital enzymes within the body contain
zinc and in these enzymes the zinc molecule acts directly
as an anti-oxidant, protecting the biochemical structure of
the enzyme from free radical attack. Secondly, zinc acts
to stabilise proteins which may otherwise react with highly
unstable minerals, particularly iron and copper, to form
free radicals.
These experimental demonstrations of zinc's anti-oxidant
activity have now been amply confirmed by studies of the
effects of zinc deficiencies and supplementation in live
humans; and some researchers have given particular
attention to zinc's activity within the brain.
Zinc is found in higher concentrations within the brain
than any other essential mineral except iron and is
believed to be particularly important in preserving the
effectiveness of the so-called "blood brain barrier" (BBB).
The purpose of the BB is to protect vital brain and
nervous system tissue from the toxins which it might
otherwise absorb through the blood supply. The potential
problem is that the BBB is made of a highly sensitive and
fragile membrane, largely comprised of fatty acids, which
is particularly vulnerable to the oxidative damage caused
by free radicals.
The supposition is therefore that oxidative stress upon the
body may lead to reduced effectiveness of the BBB, with a
consequently increased likelihood of degenerative health
problems within the brain and nervous system; the best
known of these being Alzheimer's and Parkinson's disease.
This supposition has been borne out by laboratory
experiments on rats, which have also shown that zinc
deficiency in these animals significantly reduces the
strength of the BBB.
It is perhaps not surprising, therefore, that zinc
deficiency in humans has long been associated with brain
pathologies including schizophrenia, multiple sclerosis,
dyslexia, Huntington's disease, various dementias anorexia
and depression. The logical corollary of these
well-established findings should be that adequate supplies
of dietary zinc will protect against these pathologies,
perhaps especially those degenerative ones most closely
associated with long-term oxidative stress.
Unfortunately, however, it appears that zinc is one of
those minerals which it is becoming increasingly difficult
to obtain from the daily diet. Soil depletion,
environmental pollutants and diets high in refined
carbohydrate diets are all implicated in dramatically
reducing the amount of zinc active within our bodies; and
the problem is especially acute for the elderly, whose less
efficient digestive systems often struggle to absorb
adequate amounts of the mineral, even supposing that these
are present in the diet in the first place.
And these problems are compounded by the fact that the
functions of zinc are by no means confined to brain and
nervous system health. Adequate zinc is also necessary for
the effectiveness of the immune system and wound healing,
for reproductive and sexual health, the prevention of
degenerative eye disease, the regulation of blood sugar and
the maintenance of skin health to name but a few.
Not surprisingly, therefore, nutritional therapists make a
strong case for routine zinc supplementation, particularly
for the older population, and commonly recommend a daily
protective dose of 15-25 mg of zinc per day. Both the US
and EU authorities suggest a Recommended Dietary Amount
(RDA) of 15 mg, and a good quality multi-mineral product
will commonly provide around half this quantity. Higher
doses of the single mineral are of course available when
required for tackling the conditions detailed above, but
more than 200 mg of zinc daily should not be taken for
extended periods because this may interfere with the
absorption of other minerals.
In this context it should be remembered in any case that
the body functions holistically and that all supplements of
zinc, of whatever quantity, should be taken together with
comprehensive multi-mineral and multi-vitamin preparations.
----------------------------------------------------
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