Association between dietary protein intake and bone mineral density in adolescents: a cross-sectional study

Elevated daily protein consumption was significantly correlated with enhanced bone mineral density (BMD) across multiple skeletal sites in adolescents, as observed in the National Health and Nutrition Examination Survey. These results highlight the pivotal role of dietary protein in fostering bone health in the youth.

The relationship between dietary protein intake and bone mineral density (BMD) remains inconclusive, particularly among adolescents. This study aimed to investigate the association between dietary protein intake and BMD in adolescents.

This cross-sectional study utilized data from 12-19-year-old participants in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2010. Average daily protein intake was calculated from two consecutive 24-h dietary recalls. Dual-energy X-ray absorptiometry (DXA) was used to evaluate the BMD of the total femur, femoral neck, total spine, and lumbar spine. Multivariate linear regression was used to evaluate the association between dietary protein intake and BMD, adjusted for dietary protein intake per 10 g/day and multiple covariates. Stratified analysis, interaction analysis, and sensitivity analysis were performed to assess the consistency of this relationship and identify potential modifiers.

After excluding missing data, the analysis included 2,640 adolescents. In the fully adjusted model, dietary protein intake showed a significant positive association with both total femur BMD (per 10 g/d: β = 5.25, 95% Cl = 1.69 ~ 8.82) and femoral neck BMD(per 10 g/d: β = 5.23, 95% Cl = 1.56 ~ 8.89). This positive association between dietary protein intake and BMD persisted in sensitivity analyses after multiple interpolation with all covariates missing. Subgroup analyses found no interaction between subgroups, or interaction results showed no clinical significance.

This study suggests that higher dietary protein intake is associated with increased BMD in US adolescents, highlighting the potential role of protein in adolescent bone health.