Iron deficiency is common, particularly amongst women. In the developing World the population relies largely on plant based iron, whereas in Western nations populations derive more iron from red meat. Evidence suggests that the non-haem iron from plants is not as well absorbed as the haem iron from red meat. Based on these differences it might be expected that iron deficiency is rare amongst Western populations, however this is not the case. The medical treatment for iron deficiency is a supplement of non-haem iron, usually iron sulphate. However the efficiency of such supplements are not good because the non-haem iron may not be absorbed well. For example, in one study1 pregnant Burmese women with mean serum ferritin levels of 14.15 μg/L (54.8 % of the women had serum ferritin levels below 10 μg/L) were administered 60, 120 or 240 mg of iron in the form of iron sulphate. Only those receiving 120 or 240 mg of iron saw significant improvements in their iron status.
Part of the problems with non-haem iron is the existence of a number of factors that inhibit its bioavailability. For example tea and coffee can inhibit the absorption of non haem iron in humans, although the exact reason for this inhibition is not fully understood. Another factor that can inhibit the absorption of non-haem iron is the presence of particular types of dietary fibre. For example in one study2 researchers incubated iron sulphate with a number of dietary fibres including pectin, lignin and psyllium mucilage and also with a number of chelators including ascorbic acid, EDTA (ethylenediaminetetraacetic acid), fructose, cysteine and citrate, at various pHs. The lignan and psyllium mucilage showed the greatest ability to bind the iron sulphate at the conditions that most closely resembled those of the digestive tract. Citrate and EDTA were also effective at binding iron sulphate. Dietary fibre and chelating agents present in food may therefore inhibit the absorption of non-haem iron.
The ability of psyllium mucilage and lignin to inhibit the absorption of iron sulphate has also been demonstrated in dogs3. In this model system the lignin and psyllium mucilage were highly effective at inhibiting non-haem iron absorption while the presence of pectin was less effective, and cellulose had no effect. Iron absorption is therefore a complex process that depends not just on the loss of iron from body stores, but also from the amount of iron ingested, the type of iron ingested and the presence of certain inhibitors. The matter is complicated further because some factors such as vitamin C can improve the absorption of iron. This is because vitamin C can reduce the ferrous form of iron to the ferric form, and this reduced form of iron is more easily able to interact with the gut transporters. Of course, consuming red meat is the best way to correct iron deficiencies because the haem iron in red meat is very well absorbed and inhibitors have less of an ability to lower haem iron bioavailability.
Dr Robert Barrington’s Nutritional Recommendation: Those who eat red meat frequently generally do not develop iron deficient states unless blood loss is excessive. Vegetarians and those who do not eat red meat however are more susceptible to becoming deficient in iron. If iron status is deficient or borderline, high intakes of non-haem iron are necessary to reverse the condition. In addition, avoidance of inhibitors such as certain dietary fibres and chelating agents is also necessary. Supplements of iron in the inorganic form such as iron sulphate are not well absorbed but supplements of iron that are amino acid chelated have improved absorption rates. High intakes of amino acid chelated iron supplements in the absence of known iron inhibitors are therefore the best option to reverse and iron deficient state if red meat cannot be consumed.
RdB
