Skin Carotenoids Measured by Reflection Spectroscopy Correlate with Dietary Carotenoid Intake in Racially and Ethnically Diverse US Toddlers from Houston, Texas

Background: Methods to objectively assess fruit and vegetable (FV) intake in young children are needed in order to support rigorous assessments of policies and interventions. Non-invasive skin carotenoid concentration measurements may provide a rapid assessment of toddler carotenoid and carotenoid-rich FV intake. background OBJECTIVE: The aim of this study was to evaluate the relationship between pressure-mediated reflection spectroscopy-measured skin carotenoid scores (SCSs) with proxy-reported carotenoid and FV intake in racially and ethnically diverse, US toddlers.

Design: This study was a secondary analysis of data obtained from a randomized, controlled 10-week study of the effect of an interactive healthy playgroup intervention versus classroom parent education on the diet and physical activity of toddlers. This study collected skin carotenoid and 1-week dietary intake using a 31-item semi-quantitative food frequency questionnaire analyzed by Nutrient Data System for Research nutrient database. The current study determined dietary predictors of toddler SCSs.

Participants/setting: Participants were racially and ethnically diverse toddlers (12-36 months) and adult guardian dyads (N=50) recruited from the community in Houston, TX from Fall 2018-Spring 2019.

Main outcome measures: At baseline and 10-12 weeks after baseline, SCSs were measured by pressure-mediated reflection spectroscopy (Veggie Meter (TM)), guardians reported toddler diet using a food frequency questionnaire (FFQ), and carotenoid intake was estimated from the FFQ responses using a nutrient database.

Statistical analysis: The relationship between toddler SCSs and intake of total and individual carotenoid species, and FV servings was tested using generalized linear mixed models, controlling for BMI-for-age percentiles, group assignment, and age.

Results: SCSs were positively and significantly predicted by estimated intakes of total carotenoids (p=0.002), beta-carotene (p=<0.001), and lutein & zeaxanthin (p=0.003). Reported intakes of alpha-carotene, beta-cryptoxanthin, and lycopene were not predictors of SCS. Skin carotenoid scores were predicted by estimated total FV intake (p=0.047) and vegetable intake (p=0.006), but not fruit intake (p=0.580). results CONCLUSION: These results showed that reported dietary carotenoid intake is a significant predictor of SCSs in an ethnically and racially diverse population of toddlers. Toddler skin carotenoid measurement holds promise as a rapid, objective, non-invasive biomarker of dietary carotenoid intake.