Nutrition and health literacy: A systematic review to inform future research opportunities

INTRODUCTION: The purpose of this systematic review was to examine the intersection of nutrition and health literacy, identify research gaps, and define opportunities for future research. METHODS: The search strategy included three main approaches: 1) literature searches using five electronic databases; 2) backward searching--reviewing references of articles selected for review; and 3) hand searching literature cited in reviews. Inclusion criteria were: English language, presentation of primary data, specified readability or health literacy measure, and specified nutrition-related outcome for adults. A list of articles in each database was generated; those that appeared relevant for full review were identified by two independent reviewers. The lists were compared and data were collapsed into one list of non-duplicative articles from all databases. Once the final list of relevant articles was assembled for full review, a data matrix was developed to facilitate the review process. RESULTS: A total of 892 citations were initially identified. The search was subsequently updated to include 63 additional citations through 2012, for a total of 955. After eliminating those that did not meet the inclusion criteria, the final sample yielded 38 studies, which fell into three broad categories: readability assessments (n=16); individual literacy skills assessments (n=16); and measurement development (n=6). DISCUSSION: This systematic review revealed the need for: 1) more comprehensive assessment approaches; 2) more robust experimental studies; 3) exploring the moderating and mediating roles of an individual's health literacy status on nutrition outcomes; and 4) examining long-term effects of health literacy interventions on nutrition outcomes.