Association between serum vitamin C and body mass index in adolescents aged 12-19 years

Evidence on the association between serum vitamin C (sVC) levels and obesity is limited. This study aimed to explore the relationship between sVC and body mass index (BMI) in adolescents aged 12 to 19 years.

We analyzed data from the National Health and Nutrition Examination Survey (NHANES) 2003-2006, with 3952 participants. sVC and BMI were independent variables and dependent variables, respectively. The associations of sVC with BMI were examined using multivariable linear regression models. Age, sex, and race/ethnicity were analyzed as subgroups. Then, we devised smooth curve fittings and saturation threshold analysis to address the nonlinear relationship.

sVC had a negative correlation with BMI after adjusting for all covariates (β: -1.020, 95% CI: -1.359, -0.680). In the subgroup analysis by age, sex, and race/ethnicity, there was still a negative correlation between sVC and BMI (p < 0.05). The analysis of saturation effects of sVC and BMI showed the relationship between sVC and BMI in female adolescents followed an N-shaped curve, whereas the relationship between sVC and BMI in adolescents aged 12-15 years and Mexican Americans followed a U-shaped curve.

Based on the results, proper vitamin C supplementation may be beneficial to weight loss. However, considering the threshold effect, large-scale and good-quality randomized controlled trials are required to obtain the optimal vitamin C level for weight control.