The Gut Microbiota in Stress, Mood and Eating Behaviours.

Study Overview
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Brief Summary
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Diet has a considerable influence on microbiota composition and the intake of either prebiotics (microbiota-specific food or probiotics (live microbiota species) has been shown to induce positive effects in both anxiety and depression. At present there are few studies exploring stress-related conditions such as emotional/comfort eating behaviours, particularly in individuals who have experienced early life stress and/or find stress difficult to deal with in regards to gut microbiome composition and subsequent behavioural outcomes. Early life stress has been linked to the development of bulimia nervosa and anorexia nervosa in adolescence and adulthood and since the gut microbiota has been proposed as having a causal role in the aetiology and/or maintenance of disordered eating, an empirical question is whether the microbiota may mediate the relation between stress and disordered eating. This is an investigation into the effects of chronic daily consumption of a prebiotic on stress-related eating and mood.

Detailed Description
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Following an initial screening session based on inclusion/exclusion criteria, participants will be randomly allocated into either the treatment or placebo group and provided with three weeks worth of Vivinal-GOS or maltodextrin in powder form (sachets). There will be four clinical visits as detailed below: Training on how to complete food diaries and collect saliva samples for cortisol awakening response measurements Cognitive (Affective GoNoGo and Emotion Recognition Task) and biologic measurements (blood,faecal). This also includes a stress inducing task (Fake Speech Task).Provided with supplement and invited to next session in three weeks' time. Cognitive (Affective GoNoGo and Emotion Recognition Task) and biologic measurements (blood,faecal). This also includes a stress inducing task (Fake Speech Task). (one week after last visit) collection of final faecal sample

Official Title
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The Effect of Prebiotic Galacto-oligosaccharide on Stress Related Eating Behaviours and Mood.

Conditions
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Eating Behavior, Stress, Mood

Intervention / Treatment
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* Dietary Supplement: Prebiotic
* Dietary Supplement: Maltodextrin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: A positive or negative screen for exposure to adverse childhood experiences A positive or negative screen for stress/emotional related eating behaviours Written informed consent Exclusion Criteria: Antibiotic, prebiotic or probiotic use in past three months Pre-existing gastrointestinal disorders

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Treatment Prebiotic<br>3 week daily dose of Vivinal-GOS (galacto-oligosaccharide) | Dietary Supplement: Prebiotic<br>* A daily dose for 3 weeks -14.5g per day in powder form dissolved in 200ml water. This equates to 10g GOS (VGOS is primarily 69% GOS, 23% Lactose).<br>* Other names: Vivinal-GOS;|
| Placebo Comparator: Placebo<br>3 week daily dose of Maltodextrin | Dietary Supplement: Maltodextrin<br>* A daily dose for 3 weeks -14.5g per day in powder form dissolved in 200ml water. This will be matched to VGOS for lactose (3.3g per dose of maltodextrin will be lactose).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gut microbiota composition | A comparison of the microbiota between individuals who are or are not prone to stress/emotional eating behaviours potentially due to early life stress, and whether treatment with a prebiotic (GOS) alters this. Metagenomic studies will be conducted to evidence base outcomes linked to changes in microbial population 1HNMR profiling will be used to identify biochemical/ bioactive mechanisms for regulatory needs | 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Negative affect | To observe whether treatment with GOS moderates negative affect using cognitive tasks (Affective GoNoGo and Emotion Recognition test). | 4 weeks | 
| Gut Brain Axis | To gain further understanding of the mechanisms of the GBA by examining blood and/or faecal levels of SCFAs and TRP, in relation to behavioural outcomes and microbiota populations. SCFAs in serum will be measured via blood samples (ratio of acetate, propionate and butyrate) Levels of serum propionate in relation to satiety- plasma concentrations of PYY and GLP-1 | 4 weeks | 
| Eating behaviour | To observe whether participants engage stress related eating behaviours (over-eating, eating high energy foods) and if prebiotics negate these behaviours. This will be measured via a exposure to a stressful situation (fake speech task) and subsequent food consumption (a meal will provided). | 4 weeks | 
| Stress response | To observe whether treatment with GOS moderates the stress response Cortisol awakening response will be measured via saliva samples. | 4 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Stress, Galactooligosaccharide, Prebiotic, Early life stress, Emotional eating, Gut microbiota, Short-chain fatty acids, Serotonin, Cortisol