BIOAVAILABILITY OF FE, CA, P AND MG IN FE-DEFICIENT RATS TREATED WITHDIFFERENT SOURCES OF DIETARY IRON

Iron deficiency (DO) markedly decreases the concentration of iron and calcium in the liver, femur and sternum. We investigated the effect of the source of dietary iron [ferric citrate alone (citrate diet), or c ombined with bovine blood at a proportion of 1:1 (citrate+heme diet), and ferric protein (protein-Fe diet)] on the nutritive utilization of Fe, Ca, P and Mg in anemic and healthy rats. All diets contained the s ame amount of Fe (40 mg/kg diet). In Fe-deficient rats (DT) fed citrat e, citrate+heme or protein-Fe diet the apparent digestibility coeffici ent (ADC) of Fe were 39 %, 37% and 94% greater than in the respective control groups (C); hemoglobin regeneration efficiencies (HRE) were re spectively 47%, 51%, and 172% greater than in the control groups. The ADC of Ca was not affected by Fe deficiency, whereas the ADC of Mg dec reased significantly, and that of P increased under our experimental c onditions. In Fe-deficient rats fed Fe for 10 days (DT), the concentra tions of hemoglobin approached normal values. However, serum Fe remain ed low, indicating that Fe reserves were still depleted. Hepatic and f emoral Fe concentrations were also lower in all DT groups, whereas Fe concentrations in the sternum increased significantly, suggesting an i ncrease in erythropoiesis. After supply of dietary Fe for 10 days in i ron-deficient groups (DT), Ca and P concentrations increased in sternu m, a site assumed to have higher requirements for these minerals. In t he liver these values tended to normalize, whereas in the femur Ca and P stores remained depleted. Mg concentrations after the replenishment period generally approached normality in all three organs.