Association of Diet Quality with Depression, Anxiety, and Comorbidity Symptoms in Chinese School-Aged Children

<b>Background:</b> Depression and anxiety are prevalent mental health disorders among children and adolescents, with diet quality emerging as a modifiable risk factor. However, evidence regarding the association between comprehensive diet quality and mental health in school-aged children remains limited. <b>Methods:</b> This cross-sectional study included 400 Chinese children aged 8-12 years. Diet quality was assessed using the low-burden Diet Quality Questionnaire (DQQ), from which three Global Diet Recommendations (GDRs) scores were derived: GDR-Healthy, GDR-Limit, and total GDR. Depression and anxiety symptoms were evaluated using the Children's Depression Inventory (CDI) and the Social Anxiety Scale for Children (SASC), respectively. Log-binomial regression models were used to estimate risk ratios (RRs) and 95% confidence intervals (CIs) for the associations between GDR scores and mental health symptoms (depression, anxiety, comorbidity). Subgroup analyses stratified by age and sex were conducted to explore heterogeneity. <b>Results:</b> Higher total GDR scores were associated with lower risks of depressive symptoms (RR = 0.90, 95% CI: 0.84-0.96), anxiety symptoms (RR = 0.93, 95% CI: 0.88-0.99), and their comorbidity (RR = 0.88, 95% CI: 0.79-0.97) after adjustment for age, sex, zBMI, physical activity, region of residence, only-child status and parental education. The GDR-Healthy score was independently associated with lower risks of depression symptoms (RR = 0.89, 95% CI: 0.83-0.96) and comorbidity (RR = 0.87, 95% CI: 0.79-0.95), while no significant associations between GDR-Limit score and mental health disorders were observed. Subgroup analyses indicated that the association was consistent across sex and age subgroups. <b>Conclusions:</b> Better diet quality and particularly higher intake of health-protective foods is associated with lower risks of depression, anxiety, and their comorbidity symptoms in Chinese school-aged children in this cross-sectional study. These findings support the integration of diet quality monitoring and nutritional interventions into public health strategies to promote mental health in children.