The effect of Mediterranean diet instructions on depression, anxiety, stress, and anthropometric indices: A randomized, double-blind, controlled clinical trial

Evidence suggests that adopting a healthy diet, such as the Mediterranean Diet (MD), can positively affect mental health. To further explore this, a study was conducted to determine the impact of MD instruction over 12 weeks on depression, anxiety, stress, and anthropometric indices. The study is a randomized, double-blind, controlled clinical trial with sixty participants who reported stress, anxiety, and depression conducted in Tabriz, Iran (2022–2023). They were randomly assigned to either the intervention group (n = 30), which received MD instruction, or the control group (n = 30), which received standard healthy nutrition education. Both groups were asked to follow their respective nutrition education plans for 12 weeks. After 12 weeks, depression, anxiety, and stress levels were measured using the DASS-21 questionnaire, and anthropometric indices were assessed. Initially, the unadjusted DASS-21 scores for depression, anxiety, and stress did not show significant differences between the two groups. However, after adjusting for baseline variables (model 2), all scores decreased significantly (the P-value for all scores was < 0.001). There was no significant difference in weight and BMI between the intervention and control groups. However, after adjusting the results based on baseline values (Model 2) and adherence to the program (Model 3), weight and BMI were significantly reduced in the MD group (P-values for both cases and both models were < 0.001). Overall, despite some significant findings, the results were not noticeable from a clinical perspective. The study provides some indications that following the Mediterranean diet may lead to improvements in weight and mental well-being.