Skin Carotenoids Measured by Reflection Spectroscopy Correlates with Vegetable Intake Frequency in Adolescents of Racial and Ethnic Minorities in Houston, Texas.

Background: Objective methods are needed to assess adolescent fruit and vegetable (FV) intake to better evaluate interventions aimed at improving FV intake. Skin carotenoid concentration measures provide a potential objective biomarker of FV intake, but the plausibility and robustness must be established across adolescent populations.

Objective: The objective of this study is to evaluate the relationship between pressure-mediated reflection spectroscopy-measured skin carotenoid scores (SCSs) and self-reported FV intake frequency among US racial and ethnic minority adolescents in Houston, TX.

Design: This is a secondary analysis of data collected on adolescents participating in the randomized, controlled study "Teens Committed to Health Through Activity, Relationships, and Good Eating (Take CHARGE!)."

Participants/setting: Participants were Hispanic (86.2%), African American (12.6%), and Asian (1.2%) adolescents (10-17 years of age) (N=167) who participated in a year-long healthy lifestyles program as their physical education class in Houston, TX from August 2018 to 2019.

Main outcome measures: Over the course of a year, participants' SCSs were measured by pressure-mediated reflection spectroscopy and self-reported FV intake frequency was assessed using questions from the School Physical Activity and Nutrition questionnaire at four separate time points.

Statistical analysis: The relationship between adolescent SCSs and FV intake frequency was tested using generalized linear mixed models, controlling for BMI z-score, sex, time-point, group assignment, and age.

Results: SCSs were positively predicted by self-reported intake frequencies for FV (β=2.398, p=0.028), vegetables (β=3.870, p=0.010), and orange and dark green vegetables (β=5.274, p=0.019), with no significant relationship observed with fruit intake frequency (β=1.151, p=0.613).

Conclusion: Self-reported total FV (combined), vegetable, and orange and green vegetable (combined) intake frequency is a predictor of SCSs among racial and ethnic minority adolescents in Houston, TX. Skin carotenoid measurement merits further investigation as a biomarker of vegetable intake in US adolescents.