Bioavailability of caseinophosphopeptide bound iron in the young rat

Iron forms strong and soluble complexes with 1-25 caseinophosphopeptide (CPP) issued from the enzymatic hydrolysis of beta-casein. That could prevent iron from insolubilization and low digestive absorption. Young iron deficient rats (5 mg iron/kg diet for 4 weeks) were repleted (200 mg iron/kg diet, 2 weeks) using either FeSO4 or iron bound to CPP of whole hydrolyzed beta-casein (beta-cas hydr group) or purified molecule (beta-cas (1-25) group). Two other groups were fed a control diet (200 mg/kg as FeSO4) for the 6 weeks, either ad libitum (control) or pair fed (PF) to experimental groups. A metabolic balance was performed during the 2nd week of repletion. Experimental groups displayed a higher iron absorption than control groups, but did not differ among themselves. At the end of the 2 weeks repletion period, FeSO4 and beta-cas hydr groups showed similar values of Hb, Hct, and RBC count, which were lower than control and PF groups. Hct and Hb values of the beta-cas (1-25) group were higher than beta-cas hydr and FeSO4 groups, but did not differ from control and PF animals. MCV values of control and PF groups did not differ from FeSO4 group but were lower than the beta-cas (1-25) and beta-cas hydr groups. The Fe liver content was significantly higher in peptide-bound Fe groups ((1-25) beta-cas and beta-cas hydr) than the three other groups; the FeSO4 group showed the lowest levels. Binding iron to phosphocaseino-phosphopeptide seems to improve its bioavailability and to hasten the cure of iron deficiency in the young animal. (C) Elsevier Science Inc. 1997.