Abstract
Depression is defined as a cluster of specific symptoms with associated impairment affecting 7.4% of the adolescents globally. As part of the systematic review, around 1000 relevant articles published between January 1978 and December 2017 were identified by systematic online search from 6 electronic databases (PubMed, PsycInfo, Science Direct, MEDLINE, Scopus, and Google Scholar) and overall, 56 relevant studies were included in the current review as per the inclusion criteria. Findings highlight the potential importance of the relationship between healthy dietary patterns or quality and positive mental health throughout life span. Various nutrition and dietary compounds have been suggested to be involved in the onset maintenance and severity of depressive symptoms and disorders. Nutritional compounds might modulate depression associated biomarkers. In this context, several healthy foods such as olive oil, fish, nuts, legumes, dairy products, fruits, and vegetables have been inversely associated with the risk of depression and might also improve symptoms. In contrast western dietary patterns including the consumption of sweetened beverages, fried foods, processed meats, baked products have been shown to be associated with an increased risk of depression in longitudinal studies. Diet and nutrition offer key modifiable targets for the prevention of mental disorders. Evidence is steadily growing for the relation between nutrition deficiencies, diet quality and mental health and for the efficacy and use of nutritional supplements to address deficiencies or as augmentation therapies. We advocate recognition of diet and nutrition as crucial factors in prevention and management of mental disorders.