Samsung Advanced Institute of Technology

Objective: Optical spectroscopy-measured skin carotenoid status (SCS) has been validated for estimating fruit and vegetable (F&V) intakes; however, limited research has addressed SCS kinetics in whole-diet interventions. This controlled feeding trial aimed to explore SCS’s response to carotenoid intake changes via whole-diet intervention, evaluating its biomarker potential.

Methods: Eighty participants aged 20？49, without underlying diseases, were randomly allocated to the high-carotenoid group (HG, n=40) or control group (CG, n=40). The HG consumed a high-carotenoid diet (21.0 mg total carotenoids/2000 kcal), while the CG consumed a control diet (13.6 mg total carotenoids/2000 kcal) for six weeks. Subsequently, skin and blood carotenoid concentrations were tracked without intervention for four weeks. SCS was measured weekly via resonance Raman spectroscopy, and serum carotenoid concentrations were analyzed bi-weekly using HPLC. Baseline carotenoid and F&V intakes were assessed via 3-day diet record. Kinetics of SCS and serum carotenoid concentrations were analyzed using weighted generalized estimating equation. Pearson’s correlation analyses were used to examine baseline correlations between SCS and dietary carotenoid and F&V intakes, as well as serum carotenoid concentrations.

Results: During the intervention, the HG showed a faster and greater SCS increase than the CG (difference in slope per week=8.87 AU, P-interaction<0.001). Baseline SCS had positive correlations with total carotenoid intake (r=0.45), total F&V intake (r=0.49), and total serum carotenoid concentration (r=0.79) (P<0.001 for all).

Conclusion: These results suggest that SCS is a valid biomarker for monitoring changes in carotenoid intake through whole-diet, which sup-ports the utility of SCS for assessing carotenoid-rich F&V intake.