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 US Food and Nutrition Board (FNB) Recommended Dietary Allowance (RDA) for iron is 8 mg a day for adult males and 11 mg for male adolescents. The allowance for females is higher to allow for losses during menstruation and is set at 15 mg a day for adolescents and 18 mg for adults. The requirement for iron rises dramatically during pregnancy at any age, the RDA being set at 27 mg. Post-menopause, however, the RDA for women is the same as for men.

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.