Treatment of eggshell with casein phosphopeptide reduces the severity of ovariectomy-induced bone loss

It has been generally accepted that calcium intake prevents bone loss, and frequent fracture resulted from osteoporosis. However, it is still elusive as to how effective sole calcium intake is in preventing or attenuating the severity of osteoporosis. Here, we demonstrate the effects of eggshell-casein phosphopeptide (ES-CPP), and compared these effects those of calcium supplement, for restoring ovariectomy-mediated bone loss. CPP, synthesized from the hydrolysis of casein (0.5%) using trypsin, was added to the grinded ES and was then administered to the ovariectomized (OVX) rat at 100 mg/kg for 4 weeks. Urine and feces from each group were collected each day, and were used to calculate the apparent calcium absorption rate in a day. After 4 weeks incubation, blood and femoral bones were isolated for the analysis of parameters representing osteoporosis. The apparent calcium absorption rate was significantly increased in the ES-CPP treated groups, in comparison to both the OVX and the commercial calcium supplement (CCS) treated group. Notably, treatment with ES-CPP markedly enhanced the calcium content in femoral bone and the relative weight of femoral bone to body weight, though calcium content in serum was barely changed by treatment with ES-CPP. Parameters of osteoporosis, such as osteocalcin in serum and bone mineral density, were rescued by treatment with ES-CPP, compared to treatment with commercial calcium supplement. This finding strongly suggests the possible use of ES-CPP in preventing or attenuating the severity of postmenopausal osteoporosis.