The Effect of Descriptive Social Norms on Skin Carotenoid Scores and Fruit and Vegetable Intake in College Students

Abstract

Dietary behaviors, such as fruit and vegetable (FV) intake, may be influenced by the reported behavior of peers, known as the Descriptive Social Norm (DSN). The objective of the current study was to determine how DSN regarding skin carotenoid scores, a biomarker of fruit and vegetable intake, influences FV intake. Participants were recruited from an introductory nutrition course at Utah State University in 2015. Participants (n=214) were randomly assigned to three groups. The control group received no information; the recommendation group received their skin carotenoid score and was informed that those meeting recommendations for FV had skin carotenoid scores of approximately 40,000; the DSN group received their skin carotenoid score and how their score compared to their peers. Carotenoid scans and frequency report of FV intake over the past week at baseline and 1 month after receiving the DSN information. Baseline averages for FV intake and skin carotenoid scores were 2.5 half-cup servings and 26,885, respectively, and did not differ by group. Baseline FV intake was correlated to baseline skin carotenoid score (r = .611, p = .000). Change variables were calculated and analyzed using ANOVA procedures for FV intake and skin carotenoids. No significant change was observed for either measure by group (p=.709 and p=.827, respectively). Presentation of actual DSN information had no effect on either FV intake or skin carotenoid score in this study. Future studies may evaluate longer time periods for change, or inclusion of an approval/disapproval (injunctive norm) message with DSN.