The Relationship between Protein Intake and Lean Mass in Non-Hispanic Black and East Asian Females

Low lean mass (LM) is associated with increased cardiometabolic disease risk and increased injury risk. Protein (PRO) intake is an important strategy to build and maintain LM. There is limited data quantifying PRO intake and evaluating the association between PRO intake and LM in non-athletic, young adult, female populations, and even less in females of color. The purpose of this study was to characterize PRO intake and evaluate the association between PRO intake and LM in females of color.

85 Non-Hispanic Black (n=42) and East Asian (n=43) females (Age: 22.5 ± 3.8 yrs, BMI: 23.8 ± 3.5 kg/m²) completed this study. Participants completed a 3-day dietary log. A dietary analysis software assessed total caloric intake and total PRO intake and PRO intake as a percentage of total calories (%PRO). LM was assessed using dual-energy x-ray absorptiometry. Multiple linear regression analyses were performed to assess the association between PRO intake and LM, after controlling for potential cofounding variables (e.g., race, age, MVPA).

For the full sample, PRO intake was 86.1 ± 30.0 g and %PRO was 17.4 ± 4.8%. After accounting for covariates, there were significant correlations between total PRO intake (g) and LM (p < 0.001, Δr² = 0.304) and %PRO and LM (p = < 0.001, Δr² = 0.232). PRO intake was a significant predictor of LM in NH Black (p = 0.008) and East Asian females (p = 0.005); %PRO was a significant predictor of LM for NH Black females (p = 0.035) only.

In this ethnically diverse sample of young-adult females, PRO intake and %PRO were within recommended guidelines to support LM. We found a moderate association between total PRO intake and LM in both ethnicities; however, %PRO may be a more important metric of adequate protein intake to support LM in NH Black females.