Vitamin B3, commonly known as niacin or nicotinic acid, is
one of the B complex of water soluble vitamins needed by
the body every day.
In its derivative form of nicotinamide, niacin is required
by the body for the production of coenzymes known as, if
you'll forgive the jargon, nicotinamide adenine
dinucleotide (NAD) and nicotinamide adenine dinucleotide
phosphate (NADP).
The importance of NAD and NADP may be shown by the fact
that over 200 of the body's other enzymes are dependent on
an interaction with them for an almost infinite variety of
vital functions.
The antioxidant enzymes, superoxide dismutase, catalase and
glutathione, for example, are the body's first line of
defence against highly damaging superoxide free radicals
and work in a closely complementary fashion. Each of these
anti-oxidant enzymes is formed by the body from the amino
acids in the proteins in your diet, and each is needed for
the others to function correctly.
This holistic functioning of the body is also reflected in
the dietary requirements for the successful production of
the enzymes. As well as a good supply of first-class
protein, ie that containing each of the essential amino
acids, a wide variety of vitamins and minerals are required
to allow optimal levels of enzyme manufacture.
So for example, vitamin E cannot do its work in the absence
of an adequate supply of active vitamin C. In its turn,
vitamin C cannot remain active without the presence of
glutathione. And although it is the most prevalent
anti-oxidant enzyme in the body, glutathione cannot act
effectively in the absence of the trace mineral, selenium,
and vitamins of the B complex, including B3 and B6.
In addition to its importance in assisting with the
manufacture of anti-oxidant enzymes, there is also some
evidence that levels of niacin above those required for the
avoidance of deficiency may have some protective effect
against the DNA cell damage that may be a precursor to the
development of cancer.
Intense attention has also been paid to the apparent
effectiveness of niacin (or nicotinic acid) in reducing
blood levels of Low Density Lipids (LDLs), the so-called
"bad" cholesterol, an effect recognised since 1955. It has
also been demonstrated by numerous research reports that
levels of High Density Lipids (HDLs), or "good" cholesterol
may be raised by niacin. This has given rise to
extravagant claims for niacin as a natural alternative to
conventional heart drugs, including statins. But it has to
be stressed that the beneficial effects appear to require
pharmacological doses of several grams a day, which should
only be taken under medical supervision.
In fact the recommended upper safe level of niacin intake
has been set by the Food and Nutrition Board at 35 mg a day
to avoid the unpleasant flushing of the face and body which
is a common side effect of high doses. At the other end of
the scale, the most important extreme deficiency disease
relating to vitamin B3 is known as pellagra.
Symptoms of pellagra affect the skin, the digestive system
and the brain, so sufferers may develop a heavily pigmented
rash on areas of the skin exposed to sunlight; they may
experience vomiting and diarrhea and symptoms similar to
the early signs of dementia. In the most extreme cases
pellagra can even be fatal if allowed to progress untreated.
Fortunately, however, as little as 11 mg of niacin a day
has been shown to be sufficient for the prevention of
pellagra, and the disease should never now be seen in
affluent Western societies. But the Recommended Dietary
Allowance (RDA) has been set at a slightly higher, safety,
level of 16 mg for men and 14 mg for women To put this in
perspective, a small 3oz serving of lean chicken or turkey
will provide between 5 and 7 mg, beef 3 mg; and salmon or
tuna (a particularly rich source) between 8 and 11 mg. An
unfortified cup of cereal may provide 5 mg, fortified
perhaps as much 20 mg or more.
Milk, nuts, beans and leafy green vegetables may be useful
secondary sources, but it should be noted, however, that
unrefined grains such as corn or wheat (even in the form of
wholemeal bread) are relatively poor sources because the
niacin they contain is not easily absorbed by the human
digestive system.
The RDA of 16mg should be easily achieved through a
normally well balanced daily diet, and should be enough to
prevent deficiency disease, but as always in nutrition,
mere absence of disease is not at all the same thing as
optimal health. So the sensible approach to
supplementation, and the one recommended by numerous
authorities to ensure maximum benefits, appears to be to
take a multi-vitamin or B complex supplement sufficient to
raise niacin intake to around 20 mg a day.
----------------------------------------------------
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
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