The Nutrition Literacy Assessment Instrument for Italian Subjects, NLit-IT: Exploring Validity and Reliability

The aim of this study was to test validity and reliability of the adapted version of the Nutrition Literacy Assessment Instrument (NLit) for Italian people (NLit-IT). An observational cross-sectional study was conducted, involving a convenience sample of adults (n = 74). To explore the validity of the tool, we considered both diet quality as an outcome of NL, and health literacy (HL) as a construct that presents similarities and differences with NL. Diet quality was measured by adherence to the Mediterranean Diet (Med diet) through the validated Mediterranean Diet Literature-based adherence score (MEDI-Lite). The relationship between NL level and adherence to Med diet was assessed by linear regression analysis and computing correlations between NLit-IT and MEDI-Lite scores (Spearman's Rho). Additionally, we evaluated the correlation between NLit-IT score and the level of HL (Spearman's Rho). Internal consistency and reliability were measured by Cronbach's alpha and intraclass correlation coefficient (ICC) respectively. Internal consistency (ρT = 0.78; 95% CI, 0.69-0.84) and reliability (ICC = 0.68, 95% CI, 0.46-0.85) were confirmed. In addition, NLit-IT total score was correlated with MEDI-Lite score (Rho = 0.25; p-value = 0.031) and multivariate regression analysis confirmed that NL significantly contributed to MEDI-Lite score (R² = 0.13; β = 0.13; p-value = 0.008). There was no significant association between the level of HL and NL. In conclusion, NLit-IT showed validity and reliability as a measure of NL for Italian people.