Comparison of Skin Carotenoid Content and Dietary Carotenoid Intake

Abstract

Abstract Objectives Skin Carotenoid Content (SCC) is a validated biomarker of vegetable intake. The objective of this study is to compare SCC to self-reported diet and supplement intake. Methods This cross-sectional study used baseline data from 61 participants in an ongoing intervention trial (Nutrition Interventions for Cognitive Enhancement). Participants were cognitively normal older adults (≥65 years, MMSE score >25). SCC was determined non-invasively by Resonance Raman spectroscopy (VEGGIE METER®; Longevity Link Corporation). Three measurements were taken on the fingertip and averaged. Dietary intake was obtained by 3-day diet records. A dietitian reviewed the diet records and entered the records into the Nutrition Data System for Research (version 2019). Linear regression was used to assess relationships between self-reported carotenoid intake and SCC measurement. Results The mean SCC was 279 ± 72.1. Correlations for self-reported individual carotenoid intake and SCC scores were beta-carotene (r2 = 0.15, β̞ = 0.38, P = 0.002), alpha-carotene (r2 = 0.10, β̞ = 0.32, P = 0.01), and lutein + zeaxanthin (r2 = 0.16, β̞ = 0.41, P = 0.001). Correlations for self-reported combined diet and supplement intake and SCC scores were beta-carotene (r2 = 0.15, β̞ = 0.38, P = 0.002), alpha carotene (r2 = 0.10, β̞ = 0.32, P = 0.01), and lutein + zeaxanthin (r2 = 0.07, β̞ = 0.26, P = 0.04). Neither reported diet nor diet and supplement intakes of beta-cryptoxanthin, lycopene, and retinol were related to SCC scores. Correlations for food group and SCC scores were dark vegetables (r2 = 0.15, β̞ = 0.39, P = 0.002), deep yellow vegetables (r2 = 0.09, β̞ = 0.30, P = 0.02), and total vegetable intake (r2 = 0.16, β̞ = 0.40, P = 0.001). Conclusions Within older adults, the SCC is a good indicator of dietary lutein + zeaxanthin, beta-carotene, and alpha-carotene intake. The finding that lutein + zeaxanthin relationship decreases when accounting for combined diet and supplement intake suggests need to investigate bioavailability of supplemental lutein + zeaxanthin. Funding Sources National Institutes of Health.