Investigating the Impact of Probiotics on Wellbeing in a Community

NCT07504952 — Not applicable, Completed, 85 participants, Loughborough University

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Does Alcohol Consumption Moderate the Effects of Probiotic Supplementation on Cognitive and Gastrointestinal Outcomes in a Non-clinical Sample?

Registry	NCT07504952
Status	Completed
Phase	Not applicable
Study type	Interventional; randomized, parallel, masking: quadruple, prevention
Enrollment	85 (Actual)
Sponsor	Loughborough University (Other); collaborators: Cultech Ltd
Conditions	Healthy Adult
Interventions	Probiotic Arm, Placebo Arm (Dietary supplement)
Dates	start 2025-09-28, primary completion 2026-02-20, completion 2026-03-01, first posted 2026-04-01, last updated 2026-09-10
Locations	1 site in United Kingdom

-Summary

The aim of this clinical trial is to investigate whether taking probiotics can improve thinking ability and digestive symptoms in healthy adults, and whether these effects depend on how often someone drinks alcohol. The study will also explore whether probiotics affect mental health, alcohol cravings, and drinking and eating behaviours.

The main questions it aims to answer are:

* Do probiotics improve everyday thinking, attention, and memory?
* Do probiotics reduce digestion issues or discomfort?
* Does how often someone drinks alcohol affect how much they benefit from probiotics?
* Do probiotics modulate alcohol cravings?
* Do probiotics improve mood, stress, and anxiety levels?
* Do probiotics influence drinking behaviour?
* Do probiotics influence eating behaviour?

Researchers will compare a probiotic supplement to a placebo (a look-alike product with no active ingredients) to see whether probiotics have real effects. Participants will be randomly assigned to one of these groups, and neither the participants nor the researchers will know who is receiving which treatment during the study.

Participants will:

* Take either a probiotic supplement or a placebo every day for 8 weeks
* Complete online questionnaires about their mood, thinking, eating and drinking behaviours, and digestive health at the start and end of the study
* Provide basic lifestyle and demographic information

This study aims to better understand whether probiotics could be a simple and low-cost way to support cognitive function, digestive health, and other wellbeing outcomes in generally healthy adults - and whether these benefits vary depending on how often someone drinks alcohol.

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+Arms and interventions

Arm	Type	Interventions	Description
Placebo Group	Placebo comparator	Dietary Supplement: Placebo Arm
Probiotic Group	Active comparator	Dietary Supplement: Probiotic Arm

Probiotic Arm (Dietary supplement): The participant will be randomly assigned to receive the probiotic, containing the active ingredient and live bacteria
Placebo Arm (Dietary supplement): The participant will be randomly assigned to receive the placebo, containing no active ingredient/live bacteria

+Outcome measures

Primary outcomes

85 non-clinical participants assessed for Everyday Cognitive Failures by Cognitive Failures Questionnaire 2.0 [From enrollment to the end of the treatment at 8 weeks]: Everyday cognitive functioning will be assessed using the Cognitive Failures Questionnaire 2.0 (CFQ 2.0), a 15-item self-report questionnaire measuring the frequency of cognitive lapses in daily life (e.g., memory, attention, and action errors). Each item is rated on a 5-point scale. Total scores are calculated by summing all item responses, yielding a score ranging from 0 to 60. Performance will be measured as the total CFQ 2.0 score (range 0-60), with higher scores indicating greater frequency of cognitive failures.
85 non-clinical participants assessed for Gastrointestinal Symptoms by Gastrointestinal Symptom Rating Scale [From enrollment to the end of the treatment at 8 weeks]: Gastrointestinal symptoms will be assessed using the Gastrointestinal Symptom Rating Scale (GSRS), a 15-item self-report questionnaire evaluating the severity of common gastrointestinal symptoms. Each item is rated on a 7-point Likert scale, with higher scores indicating more severe symptoms. Total scores are calculated by summing all item responses, yielding a score ranging from 15 to 105. Performance will be measured as the total GSRS score (range 15-105), with higher scores indicating greater gastrointestinal symptom severity. Domain scores may also be calculated by averaging relevant items to assess specific symptom clusters.

Secondary outcomes

85 non-clinical participants assessed for Drinking Behaviour by Loughborough Alcohol Drinking Questionnaire [From enrollment to the end of the treatment at 8 weeks]: Drinking behaviour will be assessed using the Loughborough Alcohol Drinking Questionnaire (LoAD-Q), a 33-item self-report questionnaire measuring three dimensions: emotional drinking, external drinking, and restrained drinking. Each item is rated on a 5-point Likert scale (1 = never to 5 = very often). Subscale scores are calculated by summing item responses within each dimension. The emotional drinking subscale (13 items) has a score range of 13 to 65, the external drinking subscale (10 items) ranges from 10 to 50, and the restrained drinking subscale (10 items) ranges from 10 to 50. Performance will be measured as subscale total scores, with higher scores indicating greater levels of emotional, external, and restrained drinking behaviour, respectively.
85 non-clinical participants assessed for Depression, Anxiety, and Stress by Depression Anxiety Stress Scales-12 [From enrollment to the end of the treatment at 8 weeks]: Mental health symptoms will be assessed using the Depression Anxiety Stress Scales-12 (DASS-12), a 12-item self-report questionnaire measuring symptoms of depression, anxiety, and stress. Each item is rated on a 4-point Likert scale (0-3), yielding a total score ranging from 0 to 36. Performance will be measured as the total DASS-12 score (range 0-36), with higher scores indicating greater psychological distress.
85 non-clinical participants assessed for Alcohol Craving by Penn Alcohol Craving Scale [From enrollment to the end of the treatment at 8 weeks]: Alcohol craving will be assessed using the Penn Alcohol Craving Scale (PACS), a 5-item self-report questionnaire measuring frequency, intensity, and duration of alcohol cravings over the past week. Each item is rated on a scale from 0 to 6, yielding a total score ranging from 0 to 30. Performance will be measured as the total PACS score (range 0-30), with higher scores indicating greater alcohol craving severity.

Other outcomes

85 non-clinical participants assessed for Disordered Eating by Eating Disorder Examination Questionnaire Short Form [From enrollment to the end of the treatment at 8 weeks]: Disordered eating behaviours will be assessed using the Eating Disorder Examination Questionnaire Short Form (EDE-QS), a 12-item self-report questionnaire measuring eating disorder psychopathology over the past 7 days. Each item is rated on a 4-point scale (0-3), yielding a total score ranging from 0 to 36. Performance will be measured as the total EDE-QS score (range 0-36), with higher scores indicating greater severity of disordered eating behaviours.

+Eligibility

Sex: All, ages: 18 Years to any, accepts healthy volunteers

Exclusion Criteria:

* Participants under 18 years of age
* Regular 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

+Locations (1)

Facility	City	Country	Status
Loughborough University	Loughborough	United Kingdom

+Study documents

Study Protocol (PDF, 2025-09-17)
Informed Consent Form (PDF, 2025-06-05)