Healthy Dietary Patterns’ Impact on Depressive Symptoms: A Meta-Analysis of Randomized Controlled Trials

As the search for innovative mental health treatments expands, dietary interventions have emerged as a promising approach for alleviating depressive symptoms. This thesis presents a meta-analysis of randomized controlled trials (RCTs) examining the efficacy of whole-of-diet nutritional interventions in reducing depression symptoms among adults. Grounded in Bronfenbrenner’s Bioecological Model and Engel’s Biopsychosocial Model, this study explores the intersection of biological, psychological, and social factors that influence mental health outcomes. A systematic review identified six eligible RCTs assessing the impact of healthy dietary patterns, including the Mediterranean diet and other plant-based interventions, on depression symptoms. A random-effects meta-analysis revealed a significant overall effect (Cohen’s d = -1.32, 95% CI: -2.11 to -0.52, p = 0.0011), indicating that dietary interventions are associated with large reductions in depressive symptoms. These findings highlight the potential of dietary interventions as clinically meaningful complementary strategies to traditional mental health treatments. The study contributes to growing evidence supporting nutrition-based approaches in psychiatric care and underscores the need for further research to refine dietary guidelines for mental health. Implications for clinical practice, public health policy, and culturally adaptive interventions will be discussed, emphasizing the importance of holistic and accessible approaches to mental health care.