IMPROVEMENT OF ZINC INTESTINAL-ABSORPTION AND REDUCTION OF ZINC IRON INTERACTION USING METAL-BOUND TO THE CASEINOPHOSPHOPEPTIDE-1-25 OF BETA-CASEIN/

Binding zinc (Zn) to soluble caseinophosphopeptides (CN), produced by the hydrolysis of caseins, improves its absorption and could prevent i nhibition by other nutrients such as iron (Fe). The absorption of Zn ( 100 mu mol/L) bound to the 1-25 CN (beta-CN(1-25)) of beta-casein, or as ZnSO4 was studied using the isolated, perfused rat intestinal loop system. Fe (Fe-CN or Fe gluconate (Fe Gluc)) was added at Zn/Fe ratios of 2:1, 1:5 and 1:10. Disappearance from the lumen (Q1) and net absor ption (ZnAbs) of Zn-CN were statistically greater than for ZnSO4; Zn r etention by the mucosa (Q2) did not significantly differ. Fe Glue redu ced Q1, Q2 and ZnAbs for ZnSO4 at ratios of 1:5 and 1:10 and for Zn-CN at a ratio of 1: 10. Fe-CN reduced Q1 and ZnAbs of both forms of Zn a t a ratio of 1:10; Q2 remained unchanged. Binding Zn to beta-CN(1-25) improved Zn absorption and prevented Fe from inhibiting its absorption . (C) Inra/Elsevier, Paris.