期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：2012
卷号：58
期号：4
页码：240-246
DOI：10.3177/jnsv.58.240
出版社：Center for Academic Publications Japan
摘要：Having higher bone mineral density (BMD) during growth is complexly influenced by many factors. For example, nutrition and physical exercise are key factors. However, few studies have investigated the combined effects of these factors. In this study, we investigated the effect of physical exercise and different levels of protein intake on BMD and bone strength of growing male rats. Forty-seven male Wistar rats (5 wk old) were randomized into 10% (Low), 20% (Moderate) and 40% (High) protein diet groups, and each group was further divided into exercise groups (LEx, MEx, HEx) or non-exercise groups (L, M, H). Exercise group rats were trained 6 d per week on a treadmill (25-30 m/min, 60 min) for 60 d. After being sacrificed, their BMD and bone strength were evaluated. The BMD of tibia, femoral breaking force and energy were significantly lower in the low protein diet groups than the other diet groups. In particular, the femoral breaking energy was significantly lower in the HEx group than in the H group, while there were no differences between LEx and L or MEx and M. Taken together, our data suggests that a low protein intake could suppress acquisition of bone mass and increasing bone strength during growth. Moreover, a high protein intake could also suppress bone strength during growth in which physical activity was vigorously performed. Therefore, sustaining an adequate protein intake level, around 20% protein intake, may be of significance for increasing not only bone mass but bone strength during growth.
关键词：bone mineral density;protein;physical exercise;growing phase
