Dietary protein intake among adults in the United States and its relationship to select body composition measures

Abstract

Higher protein intakes may help maintain lean body mass in adults. The purpose of this research was to examine the relationship between dietary protein and body composition measures among adults in the US, with a focus on older adults, using data from NHANES. Dietary data were from two 24‐hour recalls. Body composition data were from DXA measurements from NHANES 2003–04. SAS and SUDAAN software were used for data management and regression analyses. All analyses were performed separately by age group (19–50, 51–70, and 71+) and gender. Covariables were age, height, total energy intake, physical activity (average intensity from physical activity monitor), total body fat mass (g), race/ethnicity, and education level. Results indicate that protein intake (expressed either as g/day or % of energy) was positively associated with total lean mass (excluding bone) in males 19–50 and 51–70 (P < 0.01) and with trunk lean mass in males of all age groups. The percent of protein contributed by animal foods was positively associated with total and trunk lean mass in males 19–50 (P < 0.01). These associations were not significant in females. Findings suggest that protein intake is a modifiable factor associated with lean body mass in this nationally representative analysis of men. Supported by grants from the CSU Agricultural Research Initiative, National Cattlemen's Beef Association, and the Dairy Council of California.