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

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. This instrument validation study included a cross-sectional sample participating in up to 2 visits 1 month apart. 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. 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. 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. 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 (β = .17; multivariate coefficient = 0.10; P