Could This Common Vitamin Be The Secret Weapon in the Battle Against Depression?

Vitamin B12, occasionally also known as cobalamin, is one
of the most important and most intensively studied of the B
complex vitamins. This group of vitamins is known as the B
complex because of their biochemical similarity and because
of their close interaction and interdependence in the
performance of their numerous vital functions. So the B
complex vitamins are commonly found together in various
common food sources and, each being water soluble, will
also be excreted together from the body. A deficiency in
one of the complex is therefore almost always accompanied
by a corresponding deficiency in each of the others.

But all of that said, the consequences of a deficiency are
different in the case of each individual vitamin, and
deficiencies of B12 are particularly associated with
cardiovascular disease, a type of anaemia, Alzheimer's
disease and other dementias, and depression.

Vitamin B12 is required for the body's manufacture of the
essential amino acid, methionine and its associated enzyme,
methionine synthase, an inadequate supply of which may lead
to an excess of homocysteine, a naturally occuring protein
within the body, which is well known to be associated with
an increased risk of cardiovascular disease.

But it is also now known that sufferers from Alzheimer's
disease are often found to have low levels of vitamin B12
in their blood as well as the raised levels of homocysteine
which are also associated with more common vascular
dementias. In fact a number of studies have suggested that
low B12 and high homocysteine levels may as much as double
the risk of Alzheimer's.

Although conventional medicine remains reluctant to accept
any causal link, it might well seem to the "intelligent
layman" who takes an interest in these matters that such a
link is more likely than not. And this is particularly so
when it is remembered that vitamin B12 deficiency leads to
a reduction in the synthesis of methionine, which is known
to be essential for the methylation reactions which are in
turn vital for the health of nerve cells and
neurotransmitters.

Research has also noted a strong associative link between
vitamin B12 deficiency and depression, that widespread and
disabling, but still poorly understood and defined
condition. In fact different studies have suggested that
up to 30% of patients with depression severe enough to
require hospital admission may be deficient in vitamin B12,
and that elderly people found to be deficient in the
vitamin are twice as likely to suffer severe depression as
those with normal blood levels.

Again the conventional "wisdom" prefers to regard these
findings as an observational association rather than
evidence of a causal link. But it has been argued that
such a link may be due to B12's acknowledged role in the
synthesis of methionine and its associated enzymes, which
are vital for the effective performance of certain
neurotransmitters whose absence is known to be a factor in
depression.

Evidently Alzheimer's disease, dementia and depression are
all conditions which become more common and more severe
with advancing age, so perhaps it should be no surprise
that deficiencies of vitamin B12 are also much more
frequent in the elderly population. In fact as many as 10
-15% of the over 60s may be severely deficient, but a far
higher proportion than this are likely to fall below the
threshold required for optimum protection against these
justifiably dreaded diseases.

However, these deficiencies are unlikely to be caused by an
inadequate dietary supply. The Recommended Dietary
Allowance (RDA) for vitamin B12 is only 2.4 mcg a day, an
amount which should be readily obtainable, except perhaps
for those following a strict vegetarian regime, given that
a single 3 oz serving of fish or red meat may provide this
quantity. For those with a taste for it, sea food may
provide a great deal more, and chicken, turkey, eggs, milk
and cheese are also useful, though less lavish, sources.

But good absorption of vitamin B12 from food is heavily
dependent on the normal stomach acid and digestive enzymes,
the quantity and effectiveness of which decreases
substantially as the body ages, and on the presence in the
stomach of a specialised protein known as Intrinsic Factor.
The correct action of Intrinsic Factor requires the
presence of adequate calcium in the body, another nutrient
in which the elderly are of course notoriously likely to be
deficient.

Absorption of B12 from supplements is much less
problematic, however, because stomach acid and digestive
enzymes are not required to release the vitamin from its
protein bindings. So this is a rare case in which even
conventional medical "wisdom" recognises the value of
supplementation, at any rate for the over 50s.

So given that relatively small amounts of these vitamins
are required by the body, and that no toxicities or adverse
side effects have been reported, there really seems no
reason to run the risk of a deficiency.

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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