Reflection Spectroscopy-Assessed Skin Carotenoids Are Positively Associated With Diet Quality and Food Security Among Participants in a Community-Based Nutrition Intervention

Objective: Examined convergent validity of reflection spectroscopy-assessed skin carotenoid scores (SCS) by examining associations between SCS and (1) self-reported fruit and vegetable (F&V) intake, (2) Healthy Eating Index scores derived from 24-hour recalls, (3) food security, (4) self-efficacy for F&V intake, and (5) barriers to F&V intake. Design: Cross-sectional study Participants/Setting: We analyzed baseline data from adult participants (n = 217) who were recruited as part of an intervention study focused on mobile markets. Main Outcome Measures: Skin carotenoid scores were assessed using the Veggie Meter. Self-reported F&V intake was assessed using items from the Behavioral Risk Factor Surveillance System and the Nutrition Data Systems for Research (NDSR). Healthy Eating Index scores were derived from 24-hour recalls, and self-efficacy, barriers to F&V intake, and food security were measured using validated scales. Analyses: Pearson product-moment correlations and regression analyses were used to examine cross-sectional associations between SCS and diet, diet quality, and psychosocial measures. We assessed differences in skin carotenoids by level of food security with analysis of variance and a mixed model. Results: Participants were 85.7% female, the mean age was 49.2 years, and the mean body mass index was 32.7 kg/m². There were positive correlations between SCS and (1) Behavioral Risk Factor Surveillance System-assessed vegetable and fruit intake per day (r = 0.15, P = 0.03 and r = 0.20, P < 0.01, respectively), (2) NDSR-24 hour recall F&V servings (r = 0.24, P < 0.01, and r = 0.23, P = 0.01, respectively), (3) NDSR-24 hour recall carotenoids (r = 0.20, P = 0.03): (4) Healthy Eating Index scores (r = 0.30, P < 0.01), and (5) Self-efficacy for eating F&V (r = 0.15, P = 0.04). There was positive association between SCS and food security such that having low food security compared with high food security was associated with lower SCS (low vs high 232.6 ± 82.7 vs 293.5 ± 104.2, P = 0.002), which was attenuated when controlling for age, income, and race. Conclusions and Implications: SCS may be a useful biomarker of diet quality. Future studies could examine relationships between SCS, diet quality, and food security in additional populations.