Effects of Probiotic Supplementation on Cognitive Lapses and Gastrointestinal Symptoms in a Non-Clinical Population: A Randomised, Placebo-Controlled Trial
Phase: NA
Conditions: This Study Focus Focuses on a Non-clinical Sample of Generally Healthy Adults, and Whether Probiotics Offer Any Holistic Health Benefits
Sponsor: Loughborough University

 
 
 
 
 
Effects of Probiotic Supplementation on Cognitive 
Lapses and Gastrointestinal Symptoms in a Non-Clinical 
Population: A Randomised, Placebo-Controlled Trial 
 
 
 
 
17/09/2025 
 
 

 
Background and Rationale  
Emerging research highlights the significant role of gut inflammation and dysbiosis in a range of 
health outcomes. This study aims to explore how probiotic supplementation can improve cognitive 
function, mental health, and gastrointestinal symptoms in a non-clinical population.  
Study Objectives  
• 
Primary Aims: To assess the impact of probiotics on cognitive lapses and gastrointestinal 
symptoms  
• 
Secondary Aims: To assess the impact of probiotics on drinking behaviour, alcohol cravings, 
and mental health 
• 
Exploratory Aim: To evaluate whether probiotics affect disordered eating behaviours 
Study Design  
• 
A triple-blind, randomised, placebo-controlled trial  
• 
The study will be conducted over an 8-week period with baseline and post intervention data 
collection points  
Participants  
~80 healthy adults in the Loughborough community. Participants will be randomly put into the 
intervention or the placebo group. Exclusion criteria are:  
- 
Participants under 18 years of age  
- 
Current use of probiotics or prebiotics (in supplements or foods) within the past 4 weeks  
- 
Antibiotic use within the past 4 weeks  
- 
Chronic gastrointestinal disorders (e.g. Irritable Bowel Syndrome, Crohn’s disease, etc)  
- 
Major psychiatric conditions diagnosed (e.g., bipolar disorder, schizophrenia, etc)  
- 
Current pregnancy or breastfeeding  
Data Collection  
Participants will be asked to complete lifestyle and demographic questions, as well as the following 
online questionnaires, at baseline and at the 8-week completion mark:  
• 
Cognitive Failures Questionnaire 2.0 (CFQ 2.0) – Measures everyday cognitive lapses  
• 
Gastrointestinal Symptom Rating Scale (GSRS): Assesses gastrointestinal symptoms  
• 
Penn Alcohol Craving Scale (PACS) – Measures an individual’s craving to drink alcohol  
• 
Loughborough Alcohol Drinking Questionnaire (LoAD-Q) – Assesses drinking behaviours  
• 
Eating Disorder Examination Questionnaire (EDE-QS) – Measures disordered eating 
behaviours  
• 
Depression Anxiety Stress Scales (DASS-12) – Measures depression, anxiety and stress  
Hypotheses  
1. Probiotics will improve cognition (lower CFQ 2.0 scores)  
2. Probiotics will reduce gastrointestinal symptoms (lower GSRS scores)  
3. Probiotics will reduce alcohol cravings (lower PACS scores) 
4. Probiotics will improve mental health symptoms (lower DASS-12 scores)  
5. Probiotics will improve drinking behaviours (lower LoAD-Q scores)  
6. Probiotics will mediate eating behaviours (lower EDE-QS scores) 
Innovative Aspects  
This study brings several novel contributions to the existing literature:  

 
• 
Gut-brain axis: Investigates gut microbiota’s role in a range of health-related outcomes 
• 
A non-clinical sample: Limited probiotic research has been conducted on non-clinical 
individuals seeking preventative or holistic health improvements.  
• 
Exploration of drinking and eating behaviours: Exploring whether the gut mediates these.  
Conclusion  
This study will investigate the impact of probiotics on self-reported mental health, cognition, and 
gastrointestinal symptoms in non-clinical adults. Probiotics might offer cost-effective interventions to 
improve symptomology before disorders become fully clinical, potentially paving the way for novel 
early intervention strategies.  
The study would also provide pilot data for the next study, in which we will carry out a probiotic 
intervention on Alcohol Use Disorder patients. We will investigate the impact of probiotics on biological 
and cognitive markers in more detail through lab-based measures like cognitive tasks and blood 
samples.