Associations between ultra-processed food intake and bone mineral density in children and adolescents

The consumption of ultra-processed food (UPF) has been linked to bone metabolism in adults, but its impact on bone mineral density (BMD) in children and adolescents remains unclear. This study analysed data from 4809 children and adolescents aged 8–19 years, drawn from the National Health and Nutrition Examination Survey (NHANES) 2011–2018. UPF intake was categorised according to the NOVA classification system, with the percentage of energy derived from UPF divided into quartiles (Q1–Q4). A weighted multiple linear regression model was used to examine the relationship between UPF intake and lumbar spine BMD (LSBMD) and subtotal BMD (SBMD). Stratified analyses were conducted to explore associations across various subgroups. The results indicated that UPF intake was positively associated with LSBMD. This association was significant in girls for both LSBMD and SBMD. Positive correlations with LSBMD also emerged in 12–15 years old and specific subgroups. Moreover, mediation analysis showed total cholesterol mediated 4·8 % of the UPF–LSBMD link, and HDL-cholesterol mediated 0·9 % of the UPF–SBMD one. These findings indicate that UPF intake is associated with increased BMD in children and adolescents. Future research should further investigate the complex effects of UPF on the health of this population.