Reflection Spectroscopy Skin Carotenoids Correlate with Serum Carotenoids in School-Aged Children

BACKGROUND: Serum carotenoids are thought to reflect higher consumption of fruits and vegetables. However, venous blood draws are invasive and not suitable for pediatric populations. Reflection spectroscopy (RS) offers a noninvasive alternative for measuring carotenoids in the skin; however, the relationship between RS-assessed skin carotenoids and serum carotenoids in children remains understudied. OBJECTIVES: This study aimed to test the hypothesis that RS-assessed skin carotenoids would significantly correlate with serum and dietary carotenoids in children. METHODS: This was a cross-sectional study among children (n = 51, 11.0 ± 1.9 y). Serum carotenoids were quantified using high-performance liquid chromatography. Skin carotenoids were assessed using the Veggie Meter, a pressure-mediated RS device. Dietary carotenoids were measured via 7-d food diaries and analyzed using the Nutrition Data Systems for Research software. Height and weight were measured to calculate the BMI percentile. Log transformation was applied to all carotenoid variables to address right-skewness. Pearson's partial correlations were conducted, adjusting for age, sex, and BMI percentile. Benjamini-Hochberg false discovery rate (FDR) correction was applied for multiple comparisons. RESULTS: Most participants (76%) had a normal BMI percentile for age and sex. Skin carotenoids significantly correlated with serum lycopene (r = 0.31, P = 0.034), β-cryptoxanthin (r = 0.49, P < 0.001), β-carotene (r = 0.75, P < 0.001), lutein (r = 0.45, P = 0.002), zeaxanthin (r = 0.36, P = 0.013), and total carotenoids (r = 0.65, P < 0.001). Skin carotenoids were significantly correlated with several dietary carotenoids, including β-carotene (r = 0.48, P = 0.0095), α-carotene (r = 0.38, P = 0.041), lutein/zeaxanthin (r = 0.37, P = 0.041), and dark green vegetable intake (r = 0.43, P = 0.033). Dietary and serum carotenoids were not significantly correlated with each other after FDR correction. CONCLUSIONS: RS-assessed skin carotenoids demonstrated robust correlations with serum carotenoids, supporting their utility as a noninvasive biomarker of carotenoid status in school-aged children.