The association of plant-based dietary patterns and psychological disorders among Iranian adults

Plant-based dietary pattern, a new scoring system, has had a favorable relationship with the risk of chronic diseases, however, the associations with mental health are long disputed. Thus, we examined the association between an overall plant-based diet (PDI), healthy plant-based diet (hPDI), and unhealthy plant-based diet (uPDI) and psychological disorders in adult Iranian patients.

In this large cross-sectional study, 3,362 Iranian men and women were recruited. Dietary data were gathered using a validated and reliable Willett format food frequency questionnaire (FFQ). Plant-based dietary pattern scores were calculated based on the method of Satija et al. Psychological profile assessment was done using the validated hospital anxiety and depression scale (HADS) and the general health questionnaire (GHQ).

A total number of 943, 448, and 760 participants who suffered from depression, anxiety, and psychological distress, respectively, were identified. In the multivariable-adjusted analysis, participants in the highest category of PDI and hPDI scores had lower odds of having depression and anxiety than those in the lowest category. This association was also found between hPDI and psychological distress (OR: 0.51, 95% CI: 0.38-0.68). In contrast, higher scores of uPDI was associated with increased odds of anxiety (OR: 1.60, 95% CI: 1.06-2.42) and psychological distress (OR: 1.38, 95% CI: 1.01-1.90).

The cross-sectional study design.

Our results indicated that greater adherence to the overall plant-based diet and healthy plant-based diet was inversely associated with psychological disorders, while following unhealthy plant-based diet increased the risk of anxiety and psychological distress.