Association between Nutritional Intake Status and Appendicular Muscle Mass in Female University Students with a High Physical Activity Level*

Abstract

This study investigated the association between nutritional intake and indices of muscle mass or strength in 104 female Japanese university students who participated in sports activities during their junior and senior high school periods and had a high current physical activity level (PAL). Body composition was measured by the bioelectrical impedance method, and appendicular muscle mass (AMM) and skeletal muscle mass index (SMI) were evaluated as muscle mass. PAL was estimated using a factorial method and nutritional intake status was investigated using a food frequency questionnaire based on food groups (FFQg). Grip strength was measured as an index of muscle strength. According to the criteria for diagnosis of sarcopenia, four of the participants had low muscle mass and one also had low grip strength. Although there were no significant differences in body size or grip strength between participants with a high versus low SMI, participants with a low SMI had a significantly higher percentage of body fat (27.7 ± 4.7% vs. 23.3 ± 4.1%), and significantly lower AMM (16.0 ± 1.4 kg vs. 20.6 ± 1.5 kg), total energy intake (1770.4 ± 386.5 kcal/d vs. 2017.1 ± 389.9 kcal/d), and protein intake (57.3 ± 15.0 g/d vs. 67.0 ± 14.2 g/d), as well as a tendency to have a significantly lower carbohydrate intake (239.6 ± 49.3 g/d vs. 268.1 ± 54.4 g/d), than those with a high SMI. These results indicate that even some female university students with a high PAL have a lower muscle mass and might have a low dietary intake, mainly protein and carbohydrate. The results of multiple regression analysis of AMM, SMI, or grip strength with PAL and nutrient intake revealed that PAL and total energy intake or protein intake were significantly and positively associated with muscle mass and strength. These results suggest that a high PAL as well as total energy intake and protein intake among the macronutrients contribute to high muscle mass and muscle strength in young women.