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Iron
Is One Of The Body’s Most Vital Minerals – But You May
Well Be Getting Too Much
Iron is
probably the best known of all the essential minerals found in the human
body; and this is not surprising since it is
vital for the formation of hundreds of the proteins and enzymes on which health
depends. But iron deficiency is
nevertheless one of the commonest nutritional problems seen worldwide and is
surprisingly prevalent even in the affluent West, particularly amongst
vegetarians and those who consume little or no red meat.
Unfortunately the solution is not so straightforward as a simple program of supplementation. The problem is that the body does not easily get rid of excess iron which may therefore tend to accumulate in the body. Unused molecules of iron appear to be particularly prone to oxidation and “free radicalisation” and may contribute to the age-related degeneration of the organism associated with free radicals. Excess iron is believed to be a particular risk factor for the oxidation of the low density lipids (LDL), or “bad cholesterol” recognised as a precursor of atherosclerosis, or hardening of the arteries, a major premature killer in the West.
Sufficient
iron, however, remains vital for human health; and its best known and most
important function is in the formation of haemoglobin,
the protein in red blood cells which carries oxygen around the body. Around two-thirds of the iron in the
body is believed to be used for this purpose. Not surprisingly, since a lack of
iron means an insufficiency of oxygen being delivered to the body’s cells,
fatigue is the principal and best known deficiency symptom, reflected in a
significantly reduced ability to tolerate physical exercise or activity; but it
can also lead to headaches, dizziness, shortage of breath and even angina in
extreme cases.
But
it’s not just the red blood cells which depend on iron. White blood cells, too, and therefore
the health of the immune system, are heavily reliant on an adequate supply to
combat bacterial and viral infections; and it is worth noting that lowered
immune system responsiveness may be observed as a symptom of inadequate iron
intake well before the onset of outright anaemia.
Iron
is also an essential constituent of a number of the catalase and peroxidase
anti-oxidant enzymes which are particularly important in neutralising hydrogen peroxide, perhaps the most dangerous
of all free radicals.
Iron
has important interactions with other vital nutrients. A deficiency of vitamin A has been shown
to increase the effects of anaemia and the deficiency
condition responds better to treatment with iron when
combined with vitamin A supplementation.
Good levels of vitamin C likewise appear to assist in the body’s
absorption of iron from food sources.
It is also particularly important to ensure adequate intakes of copper
and zinc if iron is to be properly metabolised.
The
best food sources of iron are red meat, poultry and fish, although wholegrains, egg yolks and green vegetables also provide a
certain amount. However, the
consumption of calcium rich foods at the same meal is believed to reduce the
absorption of iron, as is the consumption of refined carbohydrate. Taking tea or coffee soon after a meal
will also reduce iron absorption.
So-called “heme” iron is the form found in the haemoglobin content of meat, poultry and fish. It is the
most desirable form of the mineral because although it is readily absorbed by
the body it does not accumulate within it.
Unfortunately, however, heme iron commonly
supplies only about one-third of the total obtained from the diet. Regard therefore needs to be had to the
amount of non-heme iron consumed which may build up in
the body over time, with possibly adverse consequences for health.
The
Research
in fact indicates that many adult males and post menopausal women are likely to
exceed the RDAs by consuming up to 18 mg per day of iron from their normal diet,
but this could well be a deficiency intake for individuals during adolescence,
pregnancy, menstruation and those undertaking intensive exercise regimes, all of
which may increase the body’s need for iron.
Careful
regard therefore needs always to be had to individual diet and requirements, but
iron supplements should in any case be taken only as part of a comprehensive
multi-vitamin and multi-mineral preparation. It is also especially important to note
that any iron supplementation is strongly contra-indicated for young children,
except under close medical supervision, because of a high risk of severe
toxicity.
Steve Smith
February 2008
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