Whole of Diet Approaches to Mood and Mental Health: Exploring Dietary Patterns and Depression using and Integrated Approach

Research output: ThesisDoctoral Thesis


Over 300 million people worldwide experience the symptoms of depression. Depression is a chronic, complex and multifactorial condition. While psychotherapy and psychopharmacology are the most common treatment options, they are believed to be effective in just one-third of people experiencing symptoms. Nutritional psychiatry research explores dietary patterns as an adjunct treatment alongside these options. However, the evidence base is limited by a reliance on observational research and conflicting findings across meta-analyses and systematic reviews.
This thesis uses a convergent parallel mixed-methods design encompassing three studies to address the overarching research question: Is there a relationship between dietary patterns and depression in adults? The first study is an umbrella review of all meta-analyses and systematic reviews using A MeaSurement Tool to Assess Systematic Reviews2 (AMSTAR2) and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) guidelines to determine the current state of the evidence between dietary patterns and the risk of depression. The second study is a secondary analysis of the Australian Longitudinal Study on Women’s Health (ALWSH) data. Using a linear mixed-effects modelling approach, the size and significance of an association between diet quality and depressive symptoms are investigated. Finally, a qualitative focus group study using thematic template analysis explores individuals’ experiences with food and mood within a descriptive phenomenological framework.
The umbrella review found that while many studies reported an association between dietary patterns and depression risk, the certainty of the body of evidence is very low due to high levels of measurement error, heterogeneity, and reliance on observational findings. The analysis of the longitudinal cohort study found a small, significant inverse association between diet quality on depressive symptoms after adjusting for covarying factors such as social functioning, physical activity levels, geographical location, alcohol and smoking status, marital status, body mass index and education. Four themes from the focus group studies on food and mood emerged: (i) Food in Society and Related Social Economics, (ii) Reactive and Proactive Relationships with Food, (iii) Acknowledgement of Individual Diversity Relating to Eating and Mental Health, and (iv) Improving Mood by Removing Food Restriction and Eating Intuitively.
The overall synthesis of the thesis findings suggested four key outcomes: (i) Quality and Diversity of Healthy Food and the Relationship with Mood (ii) The Link Between Food in a Social Context, Dietary Patterns and Depressive Symptoms, (iii) Population-Based Dietary Guidelines, Biodiversity and Mixed Nutrition Messages, and (iv) The Role of Food Restriction, Negative Relationships with Food and Body Image in Mental Health. Some limitations of the studies within the thesis include: the inability to correct for the differing depression terminologies and measurement error common in nutritional psychiatry research and most participants in the focus group study were noted to be diet/health-conscious and well-educated. The findings from this study may not be generalisable to a population of people who eat a traditional Western dietary pattern. Despite these limitations, the findings of this thesis suggest that while there is evidence to support the theory that there is a relationship between dietary patterns and depression, more intervention and longitudinal studies are needed to assess for causal and temporal effects and clinical significance.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Southern Cross University
  • Sargeant, Sally, Principal Supervisor
  • Bradbury, Joanne , Associate Supervisor, External person
  • Yoxall, Jacqui, Associate Supervisor, External person
Award date11 Jun 2022
Publication statusPublished - 10 Oct 2023


Dive into the research topics of 'Whole of Diet Approaches to Mood and Mental Health: Exploring Dietary Patterns and Depression using and Integrated Approach'. Together they form a unique fingerprint.

Cite this