Metabolic and Microbiota Measures as Peripheral Biomarkers in Major Depressive Disorder.

Frontiers in psychiatry. 2018;9:513
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Plain language summary

Though the connection between the gut microbiome, physical health and mental health is becoming more established, there remains a lack of understanding around the underlying cause of major depressive disorder (MDD). There is a need to identify biomarkers in MDD in order to help identify individual differences and improve treatment outcomes. The aim of this review is to investigate the link between metabolic biomarkers and the gut microbiota in individuals experiencing MDD. The current literature points to two potential biomarkers, leptin and ghrelin, which play a role in both metabolic disease and depression. Based on these findings, the authors conclude these biomarkers may help researchers and clinicians establish subgroups in depressed individuals in order to better predict treatment responses and develop more targeted therapies.


Advances in understanding the role of the microbiome in physical and mental health are at the forefront of medical research and hold potential to have a direct impact on precision medicine approaches. In the past 7 years, we have studied the role of microbiota-brain communication on behavior in mouse models using germ-free mice, mice exposed to antibiotics, and healthy specific pathogen free mice. Through our work and that of others, we have seen an amazing increase in our knowledge of how bacteria signal to the brain and the implications this has for psychiatry. Gut microbiota composition and function are influenced both by genetics, age, sex, diet, life experiences, and many other factors of psychiatric and bodily disorders and thus may act as potential biomarkers of the gut-brain axis that could be used in psychiatry and co-morbid conditions. There is a particular need in major depressive disorder and other mental illness to identify biomarkers that can stratify patients into more homogeneous groups to provide better treatment and for development of new therapeutic approaches. Peripheral outcome measures of host-microbe bidirectional communication have significant translational value as biomarkers. Enabling stratification of clinical populations, based on individual biological differences, to predict treatment response to pharmacological and non-pharmacological interventions. Here we consider the links between co-morbid metabolic syndrome and depression, focusing on biomarkers including leptin and ghrelin in combination with assessing gut microbiota composition, as a potential tool to help identify individual differences in depressed population.

Lifestyle medicine

Fundamental Clinical Imbalances : Hormonal ; Digestive, absorptive and microbiological
Patient Centred Factors : Mediators/Microbiome
Environmental Inputs : Microorganisms
Personal Lifestyle Factors : Nutrition ; Psychological
Functional Laboratory Testing : Not applicable

Methodological quality

Jadad score : Not applicable
Allocation concealment : Not applicable
Publication Type : Journal Article ; Review


Nutrition Evidence keywords : Metabolic syndrome ; MetS