The Role of Various Types of Diets in the Treatments of Depressive Disorders.

Depression is a prevalent and disabling psychiatric disorder, characterized by persistent disturbances in mood, cognition, and physiological processes, which collectively lead to substantial impairments in daily functioning and quality of life. This review provides a comprehensive overview of the biological mechanisms implicated in the pathophysiology of depression, including neurotransmitter dysregulation, oxidative stress, inflammatory processes, hypothalamic-pituitary-adrenal (HPA) axis dysfunction, mitochondrial impairment, and alterations in the gut-brain axis. Furthermore, it explores the role of diet in both the prevention and management of depression, with particular emphasis on Mediterranean, anti-inflammatory, and ketogenic dietary patterns, while contrasting these with the detrimental impact of a Western dietary pattern. Specific nutrients-such as n-3 polyunsaturated fatty acids (PUFAs), B-complex vitamins, vitamins D and E, zinc, selenium, and polyphenols-are highlighted for their potential roles in modulating neurotransmission, attenuating inflammation, and supporting gut microbiota homeostasis. Despite growing scientific interest in nutrition-based interventions, current evidence on the comparative efficacy of different dietary approaches remains limited. Future research is warranted to elucidate the therapeutic potential of dietary strategies as adjuncts to conventional treatments for depression and to facilitate the development of evidence-based nutritional recommendations for clinical practice.