칼슘과 비타민D 섭취수준이 성장기 흰 쥐의 골밀도에 미치는 영향

Abstract

The importance of an adequate calcium and vitamin D intake on the bone growth and health is universally recognized. But KNHANES indicated that dietary calcium and vitamin D intake remains inadequate regardless of age group. Thus, there is a need for a method that can complement the calcium and vitamin D intake. The Purpose of this study was to investigate the effect of calcium and vitamin D intake on bone density in growing rats. To determine the effects of milk on bone density, powdered skim milk was fed. And whey calcium was used to increase utilization of calcium. They were fed different levels of calcium and vitamin D in each groups for 5 weeks. Total of 55 Sprague Dawley male rats (5 weeks old) were divided into 7 groups according to calcium and vitamin D level. Rats were fed diet with different levels of calcium and vitamin D for 5 weeks. Control group is normal calcium normal vitamin D group (0.5 % Ca, 1,000 IU VD). Experimental group is divided into two calcium level; low(0.25%),high(1.0%) calcium. Vitamin D subgroup in low and high calcium groups divided into three levels; low(10 IU VD), normal(1,000 IU VD), high(5,000 IU VD). After 5 weeks of experiment, the femoral bone density was measured. Body weight gain was significantly higher in low calcium group than high calcium group. FER tend to be higher in low calcium group, but there were no statistically significant differences. Serum level of 25(OH)D was significantly increased with increasing dietary vitamin D levels. But serum Ca and P concentration were not affected by dietary calcium and vitamin intake among 7 groups. Although serum ALP activity and PTH concentration were not significantly different by calcium and vitamin D intake levels, serum PTH concentration was the highest in LCLD groups. In bone density analysis, BCD was higher and CaPO4 coefficient was lower in HC groups than LC groups. Bone density were not significantly different by vitamin D intake level. But BCD and BD were significantly increased with both increasing dietary calcium and vitamin D levels. BCD and BD were increased more significantly with increasing Vitamin D and calcium intake rather than calcium intake only.

According to this study, we found that powdered skim milk diet containing calcium and vitamin D had a positive effect on bone density. Higher levels of calcium and vitamin D intake are associated with greater bone density. Therefore, it could be suggested that the fortified milk with calcium and vitamin D will have a positive effect on bone density in growing adolescents.