The Nutrition Literacy Assessment Instrument is a Valid and Reliable Measure of Nutrition Literacy in Adults with Chronic Disease

Objective: To test the reliability and validity of the Nutrition Literacy Assessment Instrument (NLit) in adult primary care and identify the relationship between nutrition literacy and diet quality. Design: This instrument validation study included a cross-sectional sample participating in up to 2 visits 1 month apart. Setting/Participants: A total of 429 adults with nutrition-related chronic disease were recruited from clinics and a patient registry affiliated with a Midwestern university medical center. Main Outcome Measures: Nutrition literacy was measured by the NLit, which was composed of 6 subscales: nutrition and health, energy sources in food, food label and numeracy, household food measurement, food groups, and consumer skills. Diet quality was measured by Healthy Eating Index-2010 with nutrient data from Diet History Questionnaire II surveys. Analysis: The researchers measured factor validity and reliability by using binary confirmatory factor analysis; test-retest reliability was measured by Pearson r and the intraclass correlation coefficient, and relationships between nutrition literacy and diet quality were analyzed by linear regression. Results: The NLit demonstrated substantial factor validity and reliability (0.97; confidence interval, 0.96-0.98) and test-retest reliability (0.88; confidence interval, 0.85-0.90). Nutrition literacy was the most significant predictor of diet quality (beta = .17; multivariate coefficient = 0.10; P < .001). Conclusions: The NLit is a valid and reliable tool for measuring nutrition literacy in adult primary care patients.