Association between plant-based diets and depressive symptoms among Chinese middle-aged and older adults

This study aimed to evaluate associations between plant-based diets and the prevalence of depressive symptoms (DepS) among Chinese middle-aged and older adults. This study included 3153 participants aged 45 and older. Dietary intake was collected using a food frequency questionnaire, and DepS was evaluated using the 9-item Patient Health Questionnaire. Foods were classified into 17 groups and three plant-based diet indices were created, including the overall plant-based diet index (PDI), healthful plant-based diet index (hPDI), and unhealthful plant-based diet index (uPDI). Compared to the lowest quartile, participants in the highest quartile of hPDI had lower odds of DepS (OR = 0.60; 95% CI: 0.40, 0.89). Conversely, the highest quartile of the uPDI was associated with higher odds of DepS (OR = 1.81; 95% CI: 1.16, 2.82). These findings supported that the quality of plant-based diets matters for mental health.