wenty-eight days of vitamin D restriction and/or a high-fat diet influenced bone mineral density and body composition in young adult female rats

Vitamin D deficiency is associated with the risk of osteoporosis, and also influences skeletal muscle functions. Recently, we reported that a high-fat diet with vitamin D restriction decreased bone mineral density (BMD) in young adult male rats. Therefore, we hypothesized that vitamin D restriction and/or a high-fat diet would influence BMD in young adult female rats. Sprague-Dawley strain female rats (11-week-old) were divided into four groups: a basic control diet (Cont.), a basic control diet with vitamin D restriction (DR), a high-fat diet (F), and a high-fat diet with vitamin D restriction (FDR). At 28 days after starting the experimental diets, the weights of the soleus muscle and gastrocnemius muscle mass were significantly lower in the high-fat diet groups compared with the normal-fat diet groups. The cortical BMD of the femur was significantly lower in the DR group compared with the Cont. group, while no significant differences in the cortical, cancellous, and total BMD of the femur in the FDR were observed compared with the F group. Myogenin is one of the muscle-specific transcription factors. The levels of mRNA expression of myogenin in the gastrocnemius muscle from the DR and F groups were reduced compared with the Cont. group. We revealed the influences of vitamin D restriction and/or a high-fat diet on the BMD and muscle in young adult female rats. Further studies on vitamin D deficiency in the regulation of muscle as well as bone metabolism would provide valuable data for the prevention of osteoporosis and sarcopenia.