Skin Carotenoid Score as a Potential Early Biomarker of Metabolic Syndrome Risk in Adolescents

Background/Objectives: The increasing prevalence of overweight and obesity in adolescents represents a major global health concern. Adolescent weight gain frequently shows additional metabolic risk factors, including insulin resistance, hypertension, and dyslipidemia, whose co-occurrence defines the metabolic syndrome (MetS). Adherence to a healthy dietary pattern, such as the Mediterranean Diet (MD), has been shown to reduce the metabolic risk among adolescents. Skin carotenoid score has emerged as an objective and non-invasive indicator of MD adherence; however, its relationship with a cluster of metabolic parameters which characterize the MetS, including the triglyceride levels, diastolic blood pressure, and waist circumference, remains poorly explored. Here, we investigated the role of skin carotenoid score as an early biomarker of metabolic syndrome risk in adolescents. Methods: A sample of 634 healthy adolescents underwent anthropometric and clinical measurements, blood sample collection, and evaluation of the MD adherence by the Mediterranean Diet Quality Index for Children and Adolescents (KIDMED) questionnaire and the skin carotenoid levels by the Veggie Meter^®. Student's t-test, chi-square test, Pearson correlation, and the multivariable linear regression model were used for analyses. Results: Participants had a mean BMI Z-score of 0.02 ± 1.01; the metabolic serum profile and the cardiovascular parameters were within the normal range. Mean KIDMED and skin carotenoid scores were 5.21 ± 2.56 and 357 ± 96.58, respectively. Skin carotenoids were positively associated with height (p = 0.02), while they were inversely associated with weight (p = 0.008), BMI Z-score (p < 0.0001), diastolic blood pressure (p = 0.013), and triglycerides (p = 0.003). Moreover, the carotenoid score was positively associated with male gender and KIDMED score and negatively associated with waist circumference and triglyceride levels in multivariable regression analyses. Conclusions: Our results suggested the potential application of skin carotenoid score as a complementary biomarker for the early identification of adolescents at increased metabolic risk.