Abstract
A study was performed to investigate the bioavailability of calcium (Ca) in whey, in comparison with CaCO3 and CaHPO4. Five-week-old female rats were ovariectomized, and then fed on a low-Ca diet (Ca: 0.01%) for 27 days. Thereafter, the rats were divided into three groups, those given whey, CaCO3 and CaHPO4, respectively. Calcium balance, microdensitometric characteristics and fracture properties of the bone in each group were estimated. No significant differences in serum Ca levels, food efficiency and body weight gain were found among the three groups. On the other hand, in the whey Ca diet group, urinary Ca excretion was higher than in the other two diet groups. In the whey and CaHPO4 groups, the femur fracture properties and the parameters of microdensitometry (ΣGS, ΣGS/D, GSmin and GSmax) were increased in comparison with the CaCO3 diet group. In the whey diet group, these parameters were slightly higher than those in the CaHPO4 diet group (not significant). These results suggest that whey, as a Ca source, increases the strength of bone.
