Dietary Phytochemicals and Depressive Symptoms in Young Adults: Evidence from Undergraduate Students in Türkiye

<b>Background/Objectives:</b> Depression is a prevalent mental health problem among undergraduate students, and dietary patterns may play a role in its prevention. Phytochemical-rich diets have been proposed to be potential protective factors against depression due to their antioxidant, anti-inflammatory, and neuroprotective properties. This study aimed to investigate the association between the Dietary Phytochemical Index (DPI) and depressive symptoms among undergraduate students in Türkiye. <b>Methods:</b> A descriptive, cross-sectional study was conducted among 789 undergraduate students at Erciyes University between May 2024-May 2025. Dietary data were collected using a 101-item Food Frequency Questionnaire, and the DPI was calculated as the percentage of total daily energy derived from phytochemical-rich foods. Depressive symptoms were assessed via the Burns Depression Checklist (BDC). Statistical analyses included correlation and logistic regression models adjusted for gender, income, and academic department. <b>Results:</b> Participants with higher DPI scores exerted significantly lower BDC total and sub-dimension scores, including activities and personal relationships, physical symptoms, and suicidal urges (all <i>p</i> < 0.05). The inverse association between DPI and total depression score remained significant across all adjusted models (<i>p</i> < 0.001), and a significant linear trend was observed across DPI quartiles (<i>p</i>-trend < 0.001). <b>Conclusions:</b> Higher dietary phytochemical intake was associated with lower depressive symptom levels among undergraduate students. These results suggest that phytochemical-rich dietary patterns, characterized by increased consumption of fruits, vegetables, whole grains, legumes, and nuts, may contribute to improved psychological well-being. Promoting the intake of phytochemical-dense foods could be a practical nutritional strategy for supporting mental health in young adults.