Defining optimal body iron

The major liabilities of Fe lack include defects in psychomotor development in infants, impaired educational performance in schoolchildren, increased perinatal morbidity, and impaired work capacity. Few if any of the relevant investigations have demonstrated these abnormalities in the absence of ana emia. Consequently, adequate Fe nutrition can be defined as a normal haemog lobin concentration. On the other hand, optimal Fe nutrition should be rega rded as sufficient body Fe to avoid any limitation in tissue Fe supply, ter med Fe-deficient erythropoiesis. A variety of laboratory measurements have been used to identify this milder form of Fe deficiency, including serum fe rritin, transferrin saturation, erythrocyte protoporphyrin, mean corpuscula r volume, and more recently the concentration of the soluble fragment of tr ansferrin receptor in serum. Recent studies indicate that the serum transfe rrin receptor is the preferred measurement, because enhanced synthesis of t he transferrin receptor represent the initial cellular response to a declin ing Fe supply. Moreover, unlike other methods, it is not affected by chroni c inflammation or infection which are often confused with Fe deficiency. In an otherwise normal healthy population the transferrin receptor:ferritin v alue provides a useful quantitative index of body Fe over a wide spectrum o f Fe status, ranging from Fe repletion to Fe-deficiency anaemia. It is conc luded that optimal Fe nutrition is best defined as a normal haemoglobin, se rum ferritin and transferrin receptor concentration.