EFFECT OF CASEIN PHOSPHOPEPTIDES ON UTILIZATION OF CALCIUM IN VITAMIN-D-REPLETE AND VITAMIN-D-DEFICIENT RATS

It has been reported previously, that phosphopeptides increase calcium absorption from the ligated intestinal loop. Therefore, the effect of casein phosphopeptides on the apparent absorption, retention and femur mineralization of calcium in vivo was studied. Weanling vitamin D-replete and vitamin D-deficient rats were fed diets containing 18 wt% protein from either whey protein, whey protein plus phosphopeptides or casein. Vitamin D-replete rats fed whey protein plus phosphopeptides showed slightly higher plasma calcium levels than rats fed whey protein. Vitamin D-deficient rats fed whey protein plus phosphopeptides or casein had normal plasma calcium levels at the end of the first week of the experiment whereas the whey protein group showed hypocalcemia (1.74 mmol/l). At the end of the experiment all groups had similar plasma calcium levels. The apparent absorption and retention of calcium as well as femur dry weight, ash and calcium content were not affected by the type of milk protein or by phosphopeptides provided with the diet in vitamin D-replete or vitamin D-deficient rats. The results of this study suggest that phosphopeptides do not affect calcium absorption and utilization in rats.