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Use
Carnitine As A Versatile Anti-ageing Nutrient
Author: ©Steve P Smith
L-carnitine
is a compound derived from lysine, one of the eight essential
amino acids required by the body. Although it is often described
as a vitamin, L-carnitine is better thought of as a micronutrient
which can be manufactured within the body. Dietary sources are
important, however, because the amount of L-carnitine required
by the body may sometimes exceed its ability to produce it.
The
very name "carnitine" is derived from the Latin "carnus",
which also of course gives us the term "carniverous".
So it should be no surprise that red meat is the richest food
source of this nutrient. 3 oz of beef steak, ground beef or mince
will typically provide around 80 mg of L-carnitine; a similar
serving of pork or bacon perhaps 20-25 mg. For those unable or
unwilling to consume red meat, other sources are unfortunately
much less productive. A half pint glass of milk may provide 8mg,
fish 5mg and lean chicken a mere 3 mg. Non-animal foods are a
relatively poor source of L-carnitine.
Conventional
medical wisdom, however, is that even vegetarians should be able
to produce enough L-carnitine from their diets to avoid symptoms
of deficiency. But as always in matters of nutrition, the avoidance
of deficiency is not at all the same thing as the achievement
of optimum health. So alternative practitioners and advocates
of nutritional therapy are ever keen to stress the potential benefits
of supplementation with the acetyl-L-carnitine form of this compound,
which is much the most easily absorbed.
Acetyl-L-carnitine
has been hailed as an anti-oxidant, as a weapon in the treatment
of both chronic and acute heart disease, as an aid to the production
of energy, and as a boost for cognitive function.
Although
the evidence is not yet clear cut, it has been suggested that
acetyl-L-carnitine may play a role in reducing the production
of the stress hormone, cortisol, an over supply of which is implicated
as a factor in premature ageing and its associated diseases. It
is believed that too much cortisol may suppress levels of dehydroepiandrosterone
(DHEA), the key adrenal hormone, lavish levels of which are believed
to help protect against the degenerative diseases commonly associated
with ageing in the affluent West. Levels of DHEA begin to decline
from about the early twenties onwards, just as levels of cortisol
begin to rise, potentially creating a vicious circle of bodily
decline.
Supplementing
the diets of laboratory rats with acetyl-L-carnitine has been
shown to increase tissue levels of L-carnitine, which are known
to decline naturally with age, and to improve the metabolism of
energy within the cell mitochondria. This research has generated
considerable interest, although conventional medicine is not yet
persuaded of its long term implications, if any, for human health,
pending the results of the large scale clinical trials which are
planned.
The
evidence is much more clear cut, however, for L-carnitine's role
in tackling heart disease. A number of studies have indicated
that L-carnitine supplementation may be effective in restricting
the damage to the heart muscle that typically follows a myocardial
infarction (heart attack) and in improving the survival rates
and exercise tolerance of those suffering from progressive heart
failure or angina.
Research
also suggests that L-carnitine supplementation in the form of
acetyl-L-carnitine may slow the advance of Alzheimer's and other
forms of dementia in the elderly. Nutritional therapists also
claim that such supplementation can enhance memory and other cognitive
function in healthy young adults; a claim that conventional medicine
is of course reluctant to accept.
One
potential problem with carnitine supplementation, however, is
that absorption rates are relatively poor; only up to around 20%
as opposed to perhaps 75% from L-carnitine from food sources.
Acetyl-L-carnitine, however, is much the easiest to absorb, and
supplements in this form are readily available and recommended
by some authorities in quantities of between 500 and 1,000 mcg;
so that even at low rates of absorption a plentiful supply may
be obtained. As already noted, carnitine is a perfectly natural
substance, manufactured in the body, and supplementation in these
kind of quantities has not been shown to give rise to any side
effects other than minor gastric upset in rare cases.
So
as ever, the sensible and cost effective precaution appears to
be to combine supplementation with a normal daily diet already
well supplied with foods rich in acetyl-L-carnitine.
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