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 (F/V) intake to better evaluate interventions aimed at improving F/V intake. Skin carotenoid concentration measures provide a potential objective biomarker of F/V 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 F/V 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.

Participants and setting: Participants were Hispanic (86.2%), African American (12.6%), and Asian (1.2%) adolescents (age 10 to 17 years) (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 F/V intake frequency was assessed using questions from the School Physical Activity and Nutrition questionnaire at 4 separate time points.

Statistical analysis: The relationship between adolescent SCSs and F/V intake frequency was tested using generalized linear mixed models, controlling for body mass index z score, sex, time point, group assignment, and age.

Results: SCSs were positively predicted by self-reported intake frequencies for F/V (β = 2.398; P = .028), vegetables (β = 3.870; P =.010), and orange and dark green vegetables (β = 5.274; P = .019), with no significant relationship observed with fruit intake frequency (β = 1.151; P = .613).

Conclusions: Self-reported total F/V (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.