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, but there are two types you need to know about.
Hexavalent
chromium has wide applications for industry, but is toxic to humans both on
external skin contact and through internal consumption. Trivalent chromium, however, appears to
be not only completely safe, but potentially highly beneficial to health, and
all mentions of chromium in the remainder of this article will relate only to
this type.
Perhaps
the most important function of chromium lies in its interaction with other key
nutrients, particularly niacin (vitamin B3) and certain amino acids, to form
what is known as the “glucose tolerance factor” (GTF), which enhances the action
of insulin and consequent metabolism of glucose to produce energy within the
body. The correct metabolism of
glucose, of course, is also crucial in regulating blood sugar levels; and a lack
of insulin or a decrease in the body’s sensitivity to it may give rise to the
increased blood sugar levels characteristic of diabetes. Less well known, perhaps, is that
insulin is also important in the metabolism of dietary protein and
fat.
Although
the mechanism by which chromium enhances insulin action is not fully understood
there is evidence that supplements of up to 200 mcg a day may have some effect
in reducing the need for additional insulin in diabetics. This evidence, however, is based on
Chinese research which orthodox medical opinion remains reluctant to accept as
necessarily applicable to Western diets and obesity patterns; insisting that
more research is needed. But whilst
from the strictly scientifc point of view this may be
true, it is worth noting that the benefits were observed at relatively low and
harmless levels of supplementation.
So, as ever, regard must be had to the likely balance of risk and
reward.
Moreover,
but perhaps logically enough, it has also been suggested that a deficiency of
chromium may be a factor pre-disposing an individual towards the development of
type 2, ie late onset, or non-insulin dependent,
diabetes.
There
is also some evidence that similar deficiencies in chromium may be implicated in
increased levels of blood cholesterol, although orthodox opinion maintains that
this does not necessarily imply that supplementation in non-deficient
individuals will serve to reduce
these levels.
Chromium’s role in the metabolism of glucose, protein and fat has led to a widespread belief that it may help not only in the reduction of body fat but in the acquisition of lean muscle mass. But sadly, although there is some research to support this idea, there is at least as much which showed no such benefits, and chromium supplements should not therefore be marketed or regarded either as a bodybuilding or diet product.
Owing to the supposed paucity of information on the action
of chromium within the body, neither the
Chromium
in foods is commonly found in small, in fact minute, quantities. Moreover these amounts have been found
to vary considerably even within batches of the same food. For these reasons it is difficult to
give accurate indications of the amounts which may be expected in servings of
common foodstuffs. As a generalisation, however, it may be stated that lean meats
such as beef and turkey (especially when processed), fresh vegetables, particularly,
broccoli and green beans, are probably the richest readily available
sources.
Even these, however, will seldom provide more than around 10 mcg per serving at most, and often considerably less. It’s also important to note that the foods high in refined sugars which are so common in the modern Western diet are not only themselves low in chromium but also appear to increase the excretion of chromium from the body. Unsurprisingly, therefore, it is estimated that the average adult daily intake of chromium may be as little as 20 - 40 mcg a day, of which only around 2% may be successfully absorbed and utilised by the body, and that deficiencies of the mineral are consequently quite common.
But
if supplements of chromium are to be taken, regard must be had as always to the
holistic functioning of the body.
Chromium is absorbed best, for example, when taken in the presence of
adequate vitamin C; whereas an excessive intake of calcium by contrast, will
further restrict chromium absorption.
But taking too much chromium is likewise to be avoided because any excess
may restrict the body’s absorption of the essential minerals zinc and iron.
Happily, however, none of this need be as confusing as it may sound. Supplementing with between 50 and 200 mcg of chromium a day appears to be both safe and potentially beneficial provided it is obtained as part of a comprehensive multi-mineral supplement. But for best results, as always, this multi-mineral should be taken in conjunction with a quality multi-vitamin preparation.
Steve Smith
October 2007
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