Mediterranean diet-based intervention to improve depressive symptoms: analysis of the PREDIDEP randomized trial.

Background: The effect of an intervention based on Mediterranean diet on reducing recurrence risk or subsyndromal depressive symptoms in recovered depressed patients has not been explored.

Methods: The PREDIDEP study was a two-year randomized trial designed to assess the effect of the Mediterranean Diet enriched with extra virgin olive oil on depression recurrence. At baseline and at four, eight, 16, 20, and 24 months of follow-up, depressive symptoms were evaluated through the Beck Depression inventory. Cox regression analysis was fitted to assess the role of dietary intervention on the risk of depression recurrence. Mixed effects linear models were used to assess changes in depressive subsyndromal symptoms according to the intervention.

Results: After two years of intervention, the dietary intervention group (n = 103) compared to the control group (n = 93) showed no differences regarding depression recurrence risk as main outcome. As secondary outcomes, an improvement of depressive symptoms was yielded at four (-2.15; 95% CI = -4.00 to -0.29) and eight months (-2.42; 95% CI = -4.17 to -0.67) in the intervention group, with no changes in control group. Moreover, at 20 months, significant differences were found between groups (-3.35; 95% CI = -6.08 to -0.61).

Conclusions: An intervention with Mediterranean diet in patients with previous depressive episodes might contribute to the reduction of depressive subsyndromal symptoms.