Consumption of ultra-processed foods and drinks and major depressive disorder through gut microbiota-brain axis

Research project description

PhD will investigate the importance of the consumption of ultra-processed foods and drinks (UPF) in the advent of depression. 

There is burgeoning interest in identifying factors that palliate the high prevalence and disability of major depressive disorders (MDD). Epidemiological evidence highlights the importance of the consumption of ultra-processed foods and drinks (UPF) in the advent of depression. Beyond its poor nutritional composition, UPF have an increased number of additives, some of them containing nanoparticles, and the potential presence of components derived from food processing (e.g., acrylamide) and package (e.g., bisphenols or phthalates).  

Preclinical studies showed that some UPF components produce cytotoxicity and neuro-inflammation in glial and neuron cells. In population-based samples, we and others reported recurrent evidence of a positive association between UPF consumption and depressive symptoms, as well as with the symptom’s recurrence in MDD. Also, we found a negative association between UPF consumption and the volume within mesocorticolimbic brain networks, with inflammatory factors plating a role. Preliminary data with controlled experiments in rats consuming our own developed UPF diet from weaning showed these to increase depressive-like behaviours and have lower serotonin in frontal and hippocampal regions compared to rats under a standard diet. However, there is a significant knowledge gap on the effects that UPF consumption has on MDD, their contribution to treatment-resistance, and the mechanisms underlying these alterations in the context of whole diet in humans. UPF-induced alterations in the gut microbiota-brain axis may be one potential mechanism based on recent evidence.  

In MDD, we will investigate the association between UPF consumption and (1) the severity of depressive symptoms, and the functioning within mesocorticolimbic brain networks cross-sectionally, (2) antidepressant treatment effectiveness and resistance longitudinally, and (3) the influence of the basal mesocorticolimbic brain network functioning on this previous association. Finally, we will test the role of UPF-induced alterations in gut-metabolite and microbiota concentrations on these associations. Obtained results will complement our experiments with rats fed an already-design UPF diet. 

Academic background / Skills

Candidates must hold a degree that allows admission to the official doctoral programme at UAB.  

Additional requirements for a stronger application are: 

• Bachelor in the fields of Psychology, Biology, Biomedicine, Biomedical Engineering, Medicine or related. 
• Experience in the use of statistical packages (e.g., SPSS, R). 
• Motivation to perform research linked to the topic of the project (e.g., Nutritional Psychiatry). 
• Motivation to learn statistical approaches to analyze structural and functional brain imaging data with the use of specialized packages (e.g., MATLAB, SPM). 
• The applicant should be able to perform team oriented as well as independent work. 
• Working with a focus on objectives and results. 
• Careful in their tasks. 
• Motivation to assume new intellectual challenges and interact with an interdisciplinary group of psychiatrists, psychologists, and biologists. 

Research group/s description

Sant Pau Mental Health Research Group

We are an interdisciplinary team of psychiatrists, biologists, and psychologists involved in an ambitious research program that combines pre and clinical studies to understand the link between UPF consumption and depression.

We have extensive experience with the etiopathology and neural underpinnings of MDD and the mechanisms of action and effectiveness of psychotherapeutic and pharmacological treatments.

We led the first review on the potential mechanism of UPF features on brain changes and the association of UPF consumption, depressive traits, and brain features.

Clinical results will be complemented with comprehensive assessments of monoaminergic and kynurenine systems in rats pre and postnatally exposed to a UPF diet. The effects of UPF consumption through the gut microbiota-brain axis have been indirectly investigated in obesity conditions, and this will be explored directly in MDD in the present project.