The Relationship between Diet Quality, Measured by the Recommended Food Score, and Depression, Assessed Using the Patient Health Questionnaire-9: An Observational Study in Korea

Background: Depression is a prevalent mental health disorder that presents substantial public health challenges. Emerging evidence underscores the role of dietary patterns in mitigating depressive symptoms. This study investigated the association between diet quality, assessed using the Recommended Food Score (RFS), and depressive symptoms, evaluated with the Patient Health Questionnaire-9 (PHQ-9), in a sample of Korean adults.

Methods: This cross-sectional study analyzed data from 19,786 participants recruited from a general hospital in Korea, all of whom completed the RFS and PHQ-9 assessments. General characteristics and anthropometric indices were recorded. Statistical analyses included chi-square tests and binary logistic regression to calculate odds ratios (ORs) and 95% confidence intervals for depressive symptoms according to RFS scores, adjusting for potential confounders.

Results: Higher RFS scores were associated with reduced odds of depression in univariate (OR, 0.59; P<0.001) and multivariate (OR, 0.72; P<0.001) analyses. Sociodemographic factors, including older age, higher education, marital status, higher income, professional occupation, and regular exercise, were linked to decreased odds of depression. Conversely, female sex, current smoking, and alcohol consumption were associated with increased odds.

Conclusion: The findings reveal an inverse relationship between diet quality and depressive symptoms among Korean adults, emphasizing the potential of dietary improvements in mental health promotion. Sociodemographic factors significantly influence depression risk. Future studies should adopt longitudinal designs incorporating a wider range of variables to elucidate these complex interactions.