What is the Evidence for a Diet that promotes the Production of Short Chain Fatty Acids being effective in Reducing Symptoms of Depression in Adults: A Critical Narrative Review
By Sarah Alexandra Beecroft - Nutrition Science and Practice
Abstract
Background
Depression is a prevalent mental health condition that affects around 350 million people worldwide. With growing concern towards the economic burden and increasing incidence of the disease, the necessity for identifying new treatment routes is crucial. A growing body of research points towards diet being effective in reducing symptoms.
Aims
The aim of this research was to critically review relevant published literature to identify evidence as to whether a diet that promotes the production of short chain fatty acids (SCFAs) in the human gastrointestinal system/microbiome (e.g. fruits, vegetables, wholegrains) may be effective in reducing depressive symptoms and to explore physiological processes by which this may occur.
Methodology
A systematic search across a variety of biomedical databases was undertaken and identified a large body of research. Hand screening was then applied to appropriate papers of varying study designs (RCTs, case-controls and cross-sectional studies) which were then critically appraised using three validated tools prior to data synthesis and narrative review.
Findings
Systematic searches identified 4,035 studies. After duplicate removal and hand screening for relevance, 11 studies were selected. Validated critical appraisal tools deemed eight studies worthy of inclusion: four RCTs, two case-control and two cross-sectional/cohort. Heterogeneity between studies was a limitation, yet all the studies showed similar findings; an association between a diet that includes fruit and vegetable diversity and other high fibre foods being effective at reducing outcome measures in participants with depressive symptoms.
Conclusion
Preliminary research suggests that diet may play an important role in the prevalence and severity of depression in adults. The aetiology of depression is not yet fully understood however, it is clear that the microbiome may contribute through metabolomics. Within that area, SCFAs present an attractive and promising route for therapeutic possibilities. Recommendations are made for future research to identify these processes more clearly.
