IRON-DEFICIENCY IN DISTANCE RUNNERS A REINVESTIGATION USING FE-59-LABELING AND NONINVASIVE LIVER IRON QUANTIFICATION

In a group of male distance runners, 23 out of 45 athletes showed decr eased serum ferritin values (< 35 mu g/l). The high prevalence of a ty pical iron deficiency in runners was confirmed in a subgroup of eight athletes in which the iron meta bolism was studied in detail using rad io-iron labelling and liver iron quantification. Most of these athlete s showed an up-regulated Fe-59 absorption and a decreased liver iron c oncentration as compared to a control group. Fe-59 activity in collect ed samples of stool, urine or sweat was measured sensitively using a s hielded high-pure germanium spectrometer. In periods without running, a faecal excretion of Fe-59 equivalent to 1.5 ml blood loss/d was obse rved, which represents the normal iron excretion. Under intensive trai ning or racing conditions, a significant increase up to 4.9-6.6 ml blo od loss/day was observed, whereas excretion of Fe-59 in urine or sweat was negligible. Thus, gastrointestinal blood loss was the main reason for the slightly negative iron balance in the runners. This confirms earlier studies in the literature using qualitative blood stool testin g. A treatment with 100 mg ferrous iron/day for 3 months significantly increased the values for serum ferritin (from 34 +/- 11 to 54 +/- 18 mu g/l) and liver iron (from 105 +/- 42 to 227 +/- 67 mu g/g liver).