Validation of resonance Raman spectroscopy-measured skin carotenoid status as a biomarker for fruit and vegetable intake in Korean adults.

Blood carotenoid concentration measurement is considered the gold standard for fruit and vegetable (F&V) intake estimation; however, this method is invasive and expensive. Recently, skin carotenoid status (SCS) measured by optical sensors has been evaluated as a promising parameter for F&V intake estimation. In this cross-sectional study, we aimed to validate the utility of resonance Raman spectroscopy (RRS)-assessed SCS as a biomarker of F&V intake in Korean adults. We used data from 108 participants aged 20-69 years who completed SCS measurements, blood collection, and 3-d dietary recordings. Serum carotenoid concentrations were quantified using high-performance liquid chromatography, and dietary carotenoid and F&V intakes were estimated via 3-d dietary records using a carotenoid database for common Korean foods. The correlations of the SCS with serum carotenoid concentrations, dietary carotenoid intake, and F&V intake were examined to assess SCS validity. SCS was positively correlated with total serum carotenoid concentration (r=0.52, 95% confidence interval [CI]=0.36 to 0.64, <0.001), serum β-carotene concentration (r=0.60, 95% CI=0.47 to 0.71, <0.001), total carotenoid intake (r=0.20, 95% CI=0.01 to 0.37, =0.04), β-carotene intake (r=0.30, 95% CI=0.11 to 0.46, =0.002), and F&V intake (r=0.40, 95% CI=0.23 to 0.55, <0.001). These results suggest that SCS can be a valid biomarker of F&V intake in Korean adults.