Food literacy as a moderator in the relationship between food security and dietary diversity among adults in Seoul: based on the 2021–2023 Seoul Food Survey

BACKGROUND/OBJECTIVES Food literacy (FL) and food security are key factors influencing healthy eating and dietary diversity. This study examined whether FL moderates the relationship between food security and dietary diversity score (DDS) among adults in Seoul. SUBJECTS/METHODS Data were obtained from the 2021–2023 Seoul Food Survey and included 8,248 adults aged 18–64 yrs. The DDS was calculated based on daily intake from 5 food groups (0–5 points). Food security was classified as secure or insecure. FL was assessed using a 33-item scale across nutritional and safety, cultural and relational, and socioecological domains. Participants were grouped into three FL levels. χ2 tests, t-tests, analysis of variance, and logistic regression were performed. RESULTS Food-secure participants had significantly higher DDS (2.47 vs. 2.22, P < 0.001) and FL scores (64.03 vs. 60.85, P < 0.001), including all subdomains. The DDS gap between the secure and insecure groups was the largest among those with low FL (2.32 vs. 1.74, P < 0.001), narrowing with higher FL. In contrast, among adults with high FL, the food-insecure group showed a higher DDS than the food-secure group. A significant interaction was found between FL and food security on DDS (P for interaction < 0.001). After adjusting for confounders, the highest FL group had greater odds of high DDS (odds ratio, 2.12; 95% confidence interval, 1.84–2.43; P < 0.001). CONCLUSION FL moderates the relationship between food security and dietary diversity, with this association varying across FL levels. FL education may improve diet quality, particularly in food-insecure populations.