title: A prospective study of diet quality and mental health in adolescents.
abstract: OBJECTIVE
  A number of cross-sectional and prospective studies have now been published demonstrating inverse relationships between diet quality and the common mental disorders in adults. However, there are no existing prospective studies of this association in adolescents, the onset period of most disorders, limiting inferences regarding possible causal relationships.
  
  
  METHODS
  In this study, 3040 Australian adolescents, aged 11-18 years at baseline, were measured in 2005-6 and 2007-8. Information on diet and mental health was collected by self-report and anthropometric data by trained researchers.
  
  
  RESULTS
  There were cross-sectional, dose response relationships identified between measures of both healthy (positive) and unhealthy (inverse) diets and scores on the emotional subscale of the Pediatric Quality of Life Inventory (PedsQL), where higher scores mean better mental health, before and after adjustments for age, gender, socio-economic status, dieting behaviours, body mass index and physical activity. Higher healthy diet scores at baseline also predicted higher PedsQL scores at follow-up, while higher unhealthy diet scores at baseline predicted lower PedsQL scores at follow-up. Improvements in diet quality were mirrored by improvements in mental health over the follow-up period, while deteriorating diet quality was associated with poorer psychological functioning. Finally, results did not support the reverse causality hypothesis.
  
  
  CONCLUSIONS
  This study highlights the importance of diet in adolescence and its potential role in modifying mental health over the life course. Given that the majority of common mental health problems first manifest in adolescence, intervention studies are now required to test the effectiveness of preventing the common mental disorders through dietary modification.
authors.affiliation: Barwon Psychiatric Research Unit, Deakin University, Geelong, Australia. felice@barwonhealth.org.au
authors.forename: Felice N
authors.initials: FN
authors.lastname: Jacka
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kremer
authors.forename: Michael
authors.initials: M
authors.lastname: Berk
authors.forename: Andrea M
authors.initials: AM
authors.lastname: de Silva-Sanigorski
authors.forename: Marjorie
authors.initials: M
authors.lastname: Moodie
authors.forename: Eva R
authors.initials: ER
authors.lastname: Leslie
authors.forename: Julie A
authors.initials: JA
authors.lastname: Pasco
authors.forename: Boyd A
authors.initials: BA
authors.lastname: Swinburn
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003430:Cross-Sectional Studies; D004032:Diet / Q000009:adverse effects; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008603:Mental Health / Q000706:statistics & numerical data*; D011446:Prospective Studies