Associations of Antioxidant Status, Oxidative Stress, with Skin Carotenoids Assessed by Raman Spectroscopy (RS)

We evaluated the associations of: 1) human skin carotenoids measured by RS with conventionally measured serum carotenoids, 2) RS with serum levels of vitamins C and E, and markers of antioxidant capacity (ORAC) and oxidative stress (TBARs, urinary isoprostanes). Following approval by the University of Utah IRB, consent was obtained from 320 apparently healthy male and female corporate employees participating in their annual health risk assessment. Skin carotenoids were measured with RS 473nm excitation at a standardized location in the palm of the hand. Blood and urine samples were collected to assess serum antioxidants, ORAC and oxidative stress markers. Co‐variates included BMI, dietary and lifestyle behaviors. Pearson correlations and regression analyses (n = 295) indicated a significant correlation with skin levels and a composite serum carotenoid score (r = .80; p < 0.001). RS skin measures were also associated with serum levels of vitamins C (r = .33; p < 0.001) and E (alpha tocopherol; r = .30; p< 0.001) and inversely associated with urinary isoprostanes (r = .23; p < 0.001), but not TBARS. There was no significant difference by gender, however, older and heavier subjects had lower serum carotenoid and RS carotenoid levels than their leaner counterparts. The data suggest RS offers a safe, non‐invasive alternative to drawing blood for assessing carotenoid status, and also modestly correlates with other antioxidant nutrients (vitamins C and E).