EFFECT OF CASEIN PHOSPHOPEPTIDES ON ZINC AND CALCIUM-ABSORPTION FROM BREAD MEALS

Animal studies suggest that casein phosphopeptides (CPP), formed by pr oteolytic digestion of casein, have a positive effect on Ca availabili ty. The aim of this study was to investigate the ability of CPP to imp rove Zn and Ca absorption from phytate-containing bread meals. Secondl y, it was tested whether the Ca content of the meal influenced the eff ect of CPP on Zn absorption from a high-phytate meal. Zn and Ca absorp tion from single model meals was determined by extrinsic labeling with Zn-65 and Ca-47 and measurement of whole-body retention. Thirty-one h ealthy adults (19-30 y) divided into three groups received one of thre e meal types based on white-wheat rolls with different phytate and Ca content: A: low-phytate/high-Ca (n=10), B: high-phytate/high-Ca (n=10) and C: high-phytate/low-Ca (n=11). Each individual received the same meal type at three different occasions with 0, 250 and 1000 mg CPP add ed. CPP had no effect on Zn absorption: A: 14.3+/-4.4% ((X) over bar+/ -SD) (0 mg CPP), 16.7+/-6.6% (250 mg CPP) and 16.0+/-8.8% (1000 mg CPP ); B: 7.0+/-1.6%, 7.7+/-3.0% and 8.0+/-2.6%; C: 7.7+/-2.5%, 7.0+/-2.3% and 6.5+/-1.6%, respectively. Addition of 1000 mg CPP reduced fractio nal Ca absorption from meal A: 33.8+/-7.1%, 30.5+/-6.3% and 25.9+/-8.7 % (p<0.05), whereas CPP had no effect in meal B: 29.3+/-8.3%, 27.0+/-7 .4% and 27.6+/-11.0%. However, the absolute quantity of Ca absorbed wa s unaffected. In conclusion, Zn and Ca absorption from these meals wer e not significantly influenced by the addition of CPP. Ca addition cou ld not explain the failure of CPP to improve Zn absorption.