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WELLNESS AND NUTRITION
Moderate Drinkers
Beware – You Too Could Be Flushing
Vital Vitamin B1 Out Of Your
Body
Back in the 1930s, thiamine, also known as
vitamin B1, was one of the first compounds to be isolated and recognised as a
vitamin, that’s to say a compound essential to health which the body cannot
manufacture for itself, and which must therefore be obtained from the diet.
The functions of
thiamine within the body are highly complex biochemically, but what’s important
to know is that thiamine and its associated enzymes are essential for the
body’s production of energy from food.
As always with the B complex vitamins, however, the proper functioning
of thiamine depends on an adequate supply of the other members of the complex,
and the performance of the thiamine related enzymes in this case is
particularly dependent on the associated vitamins, riboflavin (B2) and niacin
(B3).
That said; there is a
characteristic disease of severe thiamine deficiency, beriberi, which has been
recognised for several thousand years.
This disease should never now be seen outside medical text books in
affluent Western societies, but alcoholics and heavy drinkers, for whom the
absorption of adequate thiamine presents particular problems, frequently show
symptoms.
Beriberi is regarded
as having “wet” and “dry” forms, the symptoms of the former being principally
observed in problems with the cardiovascular system, including severe fluid
retention and in severe cases even congestive heart failure. So-called “dry” beriberi is
characterised by problems with the nervous system, particularly the peripheral
nerves of the limbs, which may lead to pain and weakness in the muscles.
Beriberi may also have
serious effects on the brain, partly through increased free radical activity,
leading in extreme cases to conditions known as Wernicke’s encephalopathy
and/or Korsaloff’s amnesia or psychosis.
Wernicke’s is identified by characteristic physical nervous “ticks”, especially
unusual movements of the eyes, whereas Korsaloff’s is the term applied when
these symptoms are accompanied by severe amnesia.
If you think these
symptoms remind you of the archetypal “street wino” you’d be right, because in
advanced societies they’re most commonly found in alcoholics and heavy
drinkers, supporting the theory that malnutrition is a major contributor to
their problems. It makes sense
that this should be so. For not
only do such people tend to have very inadequate diets, but their damaged
livers also struggle to metabolise the few nutrients which they do take
in. Alcohol, of course, is also
known as a powerful diuretic, and when you consider that thiamine, in common
with the other vitamins of the B complex, is highly water soluble, and easily
excreted by the body, you have a potent recipe for nutritional disaster.
So how much thiamine do you need to avoid this disaster?
As always, the
Recommended Dietary Allowance (RDA) for thiamine (most recently established in
1998) is set at the level designed to prevent deficiencies in normally healthy
people. But of course, the
prevention of deficiency is not at all the same as thing as ensuring optimum
health, and the RDAs for thiamine are therefore set at the very low levels of
1.2 mg for men and 1.1 mg for women.
As the slight differential suggests, higher intakes are required in
proportion with higher bodyweight, and particularly muscular bodyweight. An increased intake of 1.4 mg is also
suggested for pregnant women.
A number of common
every day foods provide good sources of thiamine. A serving of fortified breakfast cereals, for example, may
provide 0.5 – 2mg, a single cup of wheatgerm 4 or more mg. A 3 oz serving of pork will contain up
to 0.75 mg, lentils, peas, brown or enriched white rice 0.2 mg, and a slice of
wholemeal bread 0.1 mg.
These figures would
seem to suggest that most people should have little difficulty in achieving
their RDA. But the problem is that
thiamine is notoriously fragile, and almost any type of processing of these
foods, including boiling or even toasting bread may dramatically reduce
thiamine content.
So it’s perhaps not
surprising that research suggests average intakes in Western societies may be
as low as 2 mg a day for men and 1.2 mg for women. These figures are worryingly close to the RDAs which, as
noted, are in any case set at a level only designed for the avoidance of
outright deficiency. Being averages,
it likely follows that there must be many people who routinely fall below them,
and there are also factors to be considered which may dramatically increase the
body’s demand for thiamine and therefore the risk of deficiency.
As well as the
consumption of alcohol, these include intensive physical exercise, normal
growth in adolescence, pregnancy and breast feeding, and feverish illnesses,
particularly malaria. As with
alcohol, heavy intakes of tea and coffee have been shown to have a severely
depleting effect on the body’s levels of thiamine, and this is due to so-called
“anti-thiamine factors”, in addition to the loss of the water soluble vitamin
which may be attributed to the diuretic effects of these drinks. There is also evidence that older
people may struggle to absorb sufficient quantities of this nutrient even when
their diet appears adequate.
There is no
recommended upper safe limit for the intake of thiamine, any excess being
easily excreted by the body, and no known toxic effects. Supplementing with thiamine is
therefore recommended for the vulnerable groups listed above, which in fact
comprise a significant proportion of the supposedly well population, and may
well be beneficial for all who seek optimal health and maximum energy
levels. The close interdependency
of the B vitamins, however, means that thiamine should be taken as part of a
supplement containing the whole complex.
The proper functioning of the vitamin also requires the presence of
adequate minerals, particularly magnesium.
Steve
Smith
September
2007
