Association Between Dietary Habits and Depressive Symptoms in University Students: A Cross-Sectional Study Using the Japanese Version of the Quick Inventory of Depressive Symptomatology (QIDS-J).

Objective Amid growing concerns about mental health among young people in Japan, particularly the rising suicide rate linked to depression, this study aimed to cross-sectionally investigate the association between dietary habits and depressive symptoms in university students, from the perspective of nutritional psychiatry. Methods A self-administered questionnaire survey was conducted using Google Forms (Google, Inc., Mountain View, CA, USA), with 451 students at Hosei University in 2022. The survey consisted of an original questionnaire on dietary habits and the Japanese version of the Quick Inventory of Depressive Symptomatology (QIDS-J). Based on the QIDS-J scores, participants were divided into two groups (with or without depressive symptoms), using a cutoff score of 6. Logistic regression analysis was used to identify associated dietary factors. Results Of the valid respondents, 46.3% exhibited mild or more severe depressive symptoms (QIDS-J ≥ 6). Logistic regression analysis revealed that factors significantly associated with depressive symptoms were the consumption of high-carbohydrate meals, skipping breakfast, having a nutritionally imbalanced diet, self-awareness of irregular eating habits, and a desire to diet. The consumption of high-carbohydrate meals was suggested to have the strongest association. Furthermore, the association regarding the intake of soft drinks was reversed between athletic dormitory students and general students, indicating that lifestyle differences acted as a confounding factor. Conclusion This study suggests that unhealthy dietary habits among university students are potentially associated with the severity of depressive symptoms. In particular, a carbohydrate-centered diet is presumed to have a significant impact on mental health. Future longitudinal studies are necessary to determine the causal relationships in greater detail.