The Relationship between Health Literacy, Nutrition Literacy, and Food Literacy and Dietary Behaviors in Adults: A Systematic Review.

contextNutrition interventions aiming to improve dietary behaviors often incorporate Health Literacy (HL), Nutrition Literacy (NL), or Food Literacy (FL), as a key component. The relationship between Health, Nutrition, and Food Literacy (HNFL) and dietary intake and diet adherence (eg, to dietary patterns or to recommended intake frequency guidelines) is unclear, and the role of the various literacy assessments remains unexamined. These gaps limit the understanding of how HNFL impacts efforts to improve dietary behaviors.

objectiveThis review aimed to examine how HNFL is associated with dietary intake and adherence to dietary patterns or guidelines, emphasizing the type and comprehensiveness of the HNFL assessments used. DATA SOURCES: Five electronic databases were used: PubMed, Web of Science, CINAHL, Psycinfo, and Communication and Mass Media Complete. DATA EXTRACTION: Data screening, extraction, and quality assessment were performed independently by 4 reviewers using the PRISMA guidelines and a scale for study quality assessment. DATA ANALYSIS: A total of 49 studies were retrieved from the 2495 originally screened; 26 assessed dietary intake and 23 assessed adherence to particular dietary recommendations. The type of HNFL assessed varied; 27 studies assessed HL, 17 assessed NL, and 5 assessed FL. Seventy-two investigations of the relationship between HNFL and dietary intake and adherence were reported: 42 identified a positive relationship (ie, higher HNFL related to better dietary intake/adherence), 28 did not show a significant relationship, and 2 identified a negative relationship (ie, higher HNFL related to poorer dietary intake/adherence). Studies involving HL showed the most positive relationships to dietary behavior, especially when using more comprehensive tools. Many studies received low quality assessment scores due to psychometric weaknesses in their HNFL tools.

conclusionAlthough the relationship between HNFL and dietary behavior and adherence remains unconfirmed, patterns in the findings suggest that increased HL, especially if assessed with robust tools, is more likely to demonstrate positive associations with positive changes in dietary behavior. Future nutrition intervention studies should carefully select HNFL tools that are robust and appropriate for their research question. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration No. CRD42024556816.