Mild-to-Moderate StressPEACENCT06991023
Prebiotic Effects on Anxiety, Cortisol, and Emotional Processing in Mild-to-Moderately Stressed Adults
A study testing Prebiotic (Bimuno®) in people with Mild-to-Moderate Stress, run by University of Reading at 1 site in United Kingdom.
Trial summary
The levels of stress that we experience as a population are continuing to rise due to financial, social and work pressures, particularly in mid-life where additional factors such as family and career often compound these issues. Read more about this study
- Who is it for?
- Ages 25 to 40 years
- Conditions the study is for
- Mild-to-Moderate Stress
- What is being tested?
- Prebiotic (Bimuno®)
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 55 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 31 Mar 2025to Feb 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 25 to 40 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Aged 25-40
- Meeting at least mildly stressed as per the stress subscale on the Depression, Anxiety and Stress Scale (DASS-42) (score of 15 or more)
Who cannot join
- Antibiotics within 3 months of enrolment
- Habitual consumption of pre-, pro-, or synbiotics within 3 months of enrolment
- Diagnosis of a mental health disorder within 6 months of enrolment
- Use of antidepressant medication within 6 months of enrolment
- Smoking (defined as having smoked anytime within a month of enrolment
- Following a vegan diet, or dairy or lactose intolerance
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- Shift workers with unsocial hours
- Current or historic gastrointestinal disorder, including IBS and IBD
- Current or historic diagnosis of type 1 or 2 diabetes, or any other metabolic disorder
- Current or historic diagnosis of any cardiovascular or related disease/illness
- Current or historic diagnosis of chronic fatigue or cancer
- Current or historic use of weight-loss drugs
- Current of historic diagnosis of any disorder affecting cortisol levels, including Cushing's
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Nutrition, Cognition & Health Lab, School of Psychology and Clinical Language Sciences, University of Reading
Reading, Berkshire, RG6 6ES
About this study
Official title: A Randomised Controlled Trial Exploring the Effects of Prebiotics for Mental Strain and Physiological Markers of Stress in Healthy, Mild-to-Moderately Stressed Adults
The levels of stress that we experience as a population are continuing to rise due to financial, social and work pressures, particularly in mid-life where additional factors such as family and career often compound these issues. When we experience high levels of stress for prolonged periods, this often has detrimental effects on our mental and physical wellbeing, leading to chronic illness and mental health disorders.
Prebiotics are non-digestible fibres found in food and supplements which promote the growth of beneficial bacteria that produce short-chain fatty acids (SCFAs). Research shows that prebiotics may be used as a lifestyle intervention to support individuals experiencing stress and help reduce physiological and psychological feelings of stress.
As such, this study will build on previous research and explore whether a prebiotic supplement (Bimuno®) has a beneficial effect on stress, mental health outcomes, and sleep in mild-to-moderately stressed adults. To address these questions, participants will take the prebiotic or a placebo for 6 weeks, and visit the University of Reading to complete some questionnaires and cognitive tests at the start and end of the trial. The investigators will also ask participants to collect saliva samples to see if the prebiotics influence cortisol levels, which are linked to stress.
Read the detailed description
The study employs a parallel groups, randomised, placebo-controlled design in 55 (allowing for 10% attrition) adults aged 25 - 40 experiencing mild-to-moderate stress. Information sheet, consent form, screening and collection of demographic data will be conducted via Redcap at the start of the study. Each participant will then attend 3 in-person sessions at the UoR Psychology department - 1 practice session, and 2 study visits 6 weeks apart. Between the study visits, participants will be required to consume a prebiotic supplement (Bimuno®) once a day at home, and collect saliva samples on 4 occasions.
Screening (all conducted via Redcap) All participants will read through the participant information sheet and sign the consent form before completing a health and lifestyle screening questionnaire to collect demographic data and ensure they meet the eligibility criteria. If eligible, subjects will then be invited to attend an in-person practice visit.
Practice visit The practice visit will be conducted in the Nutrition, Cognition and Health lab in the Psychology department, at any time of day (within working hours) to suit the participant. During this visit, the researcher will double-check participant eligibility and talk the subject through the full trial protocol. Participants will then complete the mood questionnaires and one practice round of the cognitive task (detailed in the study visit section below). This allows participants to see the type of questions they will be asked and ensure they're comfortable answering them, as well as ensure competency on the task before collecting data in the study visits. Finally, participants will be provided with two cycles worth of saliva sample kits and a demonstration on how collect their saliva samples.
Study visit(s) Subjects will consume a standardised breakfast of one slice of white toast and butter with water at home prior to arrival (or, if the participant does not routinely eat breakfast, they may arrive for the visits fasted). Study visits will be conducted in the Nutrition, Cognition and Health lab in the Psychology department, and participants will have the option to arrive anytime between 8am and 11am. This allows participants to complete their study visits before starting their work day if necessary, but also ensures that all sessions are complete before lunch removing the need to provide standardised lunch for participants. Start time of sessions will be kept consistent across visits within participants, as will the choice to have breakfast or not. During the study visits, participants will complete the following mood and sleep questionnaires in a fixed order using Redcap.
Following the questionnaires, participants will complete two emotional cognition tasks in order to explore how the prebiotic supplement might affect emotional processing. All measures will be administered via Inquisit.
At the end of the first study visit, subjects will be provided with their intervention sachets and two more cycles-worth of saliva kits to be used at the end of the study. At the end of the second visit, participants will be given the debrief sheet and emailed a payment form to complete. Both the prebiotic and the matched placebo are supplied by Clasado Research Services Ltd, Reading UK.
- Conditions
- Mild-to-Moderate Stress
- Being tested
- Prebiotic (Bimuno®), Placebo
- Keywords
- Randomised Controlled Trial, Stress, Cortisol, Prebiotic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Prebiotic (Bimuno®)Dietary supplement
The prebiotic supplement (Bimuno®) is a galactooligosaccharide (GOS) supplement derived from lactose which is publicly available and sold in the UK. Subjects will consume a daily dose of 2.75g GOS (3.65g total powder) which will be administered in sachets and consumed with breakfast by mixing into water, tea or coffee, or sprinkling on top of/mixing into food.
PlaceboDietary supplement
A matched placebo for the prebiotic intervention, containing 3.65g of maltodextrin. Consumed in the same manner as the prebiotics.
| Study group | Role | What they receive |
|---|---|---|
| Prebiotic | Experimental | The prebiotic supplement (Bimuno®) is a galactooligosaccharide (GOS) supplement derived from lactose which is publicly available and sold in the UK. Subjects will consume a daily dose of 2.75g GOS (3.65g total powder) which will be administered in sachets and consumed with breakfast by mixing into water, tea or coffee, or sprinkling on top of/mixing into food. Receives: Dietary Supplement: Prebiotic (Bimuno®) |
| Placebo | Placebo comparator | The matched placebo contains 3.65g sachets of maltodextrin, and is consumed in the same manner as the prebiotic. Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Perceived Stress Scale (PSS)
The PSS is a widely used psychological instrument for measuring the perception of stress. Items were designed to tap how unpredictable, uncontrollable, and overloaded respondents find their lives. The scale also includes a number of direct queries about current levels of experienced stress. The questions in the PSS ask about feelings and thoughts during the last month. In each case, respondents are asked how often they felt a certain way using the following 5-point Likert scale: 0 = Never, 1 = Almost Never, 2 = Sometimes, 3 = Fairly Often, 4 = Very Often.
Measured: Baseline
Perceived Stress Scale (PSS)
The PSS is a widely used psychological instrument for measuring the perception of stress. Items were designed to tap how unpredictable, uncontrollable, and overloaded respondents find their lives. The scale also includes a number of direct queries about current levels of experienced stress. The questions in the PSS ask about feelings and thoughts during the last month. In each case, respondents are asked how often they felt a certain way using the following 5-point Likert scale: 0 = Never, 1 = Almost Never, 2 = Sometimes, 3 = Fairly Often, 4 = Very Often.
Measured: Post-intervention (6 weeks)
Secondary outcomes (20)
Positive and Negative Affect Schedule - expanded (PANAS-x)
The PANAS-x is a self-report mood questionnaire measuring overall Positive (PA) and Negative Affect (NA), as well as 11 primary affects including Fear, Sadness, Guilt, Hostility, Shyness, Fatigue, Surprise, Joviality, Self-Assurance, Attentiveness, and Serenity. Participants will be asked to think about how they've been feeling over the past few weeks when using a 5-point Likert scale ranging from 'Very slightly or not at all'; 'A little'; 'Moderately'; 'Quite a bit'; to 'Extremely' to rate each of the 60 adjectives. Scores for the PA and NA subscales range from 0-50. Higher PA scores indicate more positive mood. Higher NA scores indicate more negative mood.
Measured: Baseline
Positive and Negative Affect Schedule - expanded (PANAS-x)
The PANAS-x is a self-report mood questionnaire measuring overall Positive (PA) and Negative Affect (NA), as well as 11 primary affects including Fear, Sadness, Guilt, Hostility, Shyness, Fatigue, Surprise, Joviality, Self-Assurance, Attentiveness, and Serenity. Participants will be asked to think about how they've been feeling over the past few weeks when using a 5-point Likert scale ranging from 'Very slightly or not at all'; 'A little'; 'Moderately'; 'Quite a bit'; to 'Extremely' to rate each of the 60 adjectives. Scores for the PA and NA subscales range from 0-50. Higher PA scores indicate more positive mood. Higher NA scores indicate more negative mood.
Measured: 6 weeks
Patient Health Questionnaire-8 (PHQ-8)
The 8-item version of the Patient Health Questionnaire is a widely used self-report screening questionnaire for depression severity. 8 items are scored using a scale from 8 0 (Not at all) to 3 (Nearly every day), referring to the presence of that symptom during the previous 2 weeks. The PHQ-8 score is the sum of the scores from each of the eight items, and ranges from 0 to 24. Higher scores indicate more severe depression.
Measured: Baseline
Patient Health Questionnaire-8 (PHQ-8)
The 8-item version of the Patient Health Questionnaire is a widely used self-report screening questionnaire for depression severity. 8 items are scored using a scale from 8 0 (Not at all) to 3 (Nearly every day), referring to the presence of that symptom during the previous 2 weeks. The PHQ-8 score is the sum of the scores from each of the eight items, and ranges from 0 to 24. Higher scores indicate more severe depression.
Measured: Post-intervention (6 weeks)
General Anxiety Disorder-7 (GAD-7)
The GAD-7 is a widely used initial screening tool for General Anxiety Disorder, comprising of 7 items which are scored from 0 (not at all) - 3 (nearly every day). Total score for the seven items ranges from 0 to 21, where 0-4: minimal anxiety, 5-9: mild anxiety, 10-14: moderate anxiety, and 15-21: severe anxiety.
Measured: Baseline
General Anxiety Disorder-7 (GAD-7)
The GAD-7 is a widely used initial screening tool for General Anxiety Disorder, comprising of 7 items which are scored from 0 (not at all) - 3 (nearly every day). Total score for the seven items ranges from 0 to 21, where 0-4: minimal anxiety, 5-9: mild anxiety, 10-14: moderate anxiety, and 15-21: severe anxiety.
Measured: Post-intervention (6 weeks)
Pittsburgh Sleep Quality Index (PSQI)
A self-reported measure of sleep quality and disturbances over the past month. Each of the questionnaire's 19 self-reported items belongs to one of seven subcategories: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Scores for each question range from 0 to 3, with higher scores indicating more acute sleep disturbances.
Measured: Baseline
Pittsburgh Sleep Quality Index (PSQI)
A self-reported measure of sleep quality and disturbances over the past month. Each of the questionnaire's 19 self-reported items belongs to one of seven subcategories: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Scores for each question range from 0 to 3, with higher scores indicating more acute sleep disturbances.
Measured: Post-intervention (6 weeks)
Salivary Cortisol
Cortisol (nmol/L), as measured through saliva samples, provides a biomarker of stress, and will be used in the present study to assess whether prebiotic supplementation influences the HPA axis and physiological markers of stress. Saliva samples will be collected in 'sample cycles', with each cycle including 4 time points : 1) before bed, 2) immediately upon waking, 3) 30 minutes after waking, and 4) 45 minutes after waking. Cycles will be collected on two consecutive days at baseline and two consecutive days post-intervention to ensure accurate data.
Measured: 1 day before baseline
Salivary Cortisol
Cortisol (nmol/L), as measured through saliva samples, provides a biomarker of stress, and will be used in the present study to assess whether prebiotic supplementation influences the HPA axis and physiological markers of stress. Saliva samples will be collected in 'sample cycles', with each cycle including 4 time points : 1) before bed, 2) immediately upon waking, 3) 30 minutes after waking, and 4) 45 minutes after waking. Cycles will be collected on two consecutive days at baseline and two consecutive days post-intervention to ensure accurate data.
Measured: Baseline
Salivary Cortisol
Cortisol (nmol/L), as measured through saliva samples, provides a biomarker of stress, and will be used in the present study to assess whether prebiotic supplementation influences the HPA axis and physiological markers of stress. Saliva samples will be collected in 'sample cycles', with each cycle including 4 time points : 1) before bed, 2) immediately upon waking, 3) 30 minutes after waking, and 4) 45 minutes after waking. Cycles will be collected on two consecutive days at baseline and two consecutive days post-intervention to ensure accurate data.
Measured: 1 day before post-intervention measures (6 weeks)
Salivary Cortisol
Cortisol (nmol/L), as measured through saliva samples, provides a biomarker of stress, and will be used in the present study to assess whether prebiotic supplementation influences the HPA axis and physiological markers of stress. Saliva samples will be collected in 'sample cycles', with each cycle including 4 time points : 1) before bed, 2) immediately upon waking, 3) 30 minutes after waking, and 4) 45 minutes after waking. Cycles will be collected on two consecutive days at baseline and two consecutive days post-intervention to ensure accurate data.
Measured: Post-intervention (6 weeks)
Epic-Norfolk Food Frequency Questionnaire
The FFQ is a validated tool for gauging the average habitual dietary intake of micro and macronutrients of an individual in the UK. Data will be processed using the FETA software.
Measured: Baseline
FibreScreen
A short fibre screening questionnaire, the 18-item FiberScreen was developed and validated to reduce the burden of dietary screening of fibre intake for both participant and researcher. The FiberScreen includes questions about fruits, dried fruits, vegetables, bread, whole grain, pasta/rice/potato, legumes and nuts and seeds intake of the last 2 weeks.
Measured: Baseline
FibreScreen
A short fibre screening questionnaire, the 18-item FiberScreen was developed and validated to reduce the burden of dietary screening of fibre intake for both participant and researcher. The FiberScreen includes questions about fruits, dried fruits, vegetables, bread, whole grain, pasta/rice/potato, legumes and nuts and seeds intake of the last 2 weeks.
Measured: Post-intervention (6 weeks)
Emotion dot probe task
A cognitive task which is used to measure attentional biases towards emotional stimuli. Participants respond to a probe (letter) appearing in the location of either a neutral or emotional word. Faster responses when the probe appears in the location of the emotional stimulus indicates a bias towards the emotional stimulus. Outcome measures include: accuracy when probe is presented in position of negative stimuli (negative trial, congruent); accuracy when probe is presented in position of neutral stimuli (negative trial, incongruent); accuracy when probe is presented in position of positive stimuli (positive trial, congruent); accuracy when probe is presented in position of neutral stimuli (positive trial, incongruent); RT for negative congruent \& incongruent; RT for positive congruent \& incongruent; negative attentional bias; positive attentional bias.
Measured: Baseline
Emotion dot probe task
A cognitive task which is used to measure attentional biases towards emotional stimuli. Participants respond to a probe (letter) appearing in the location of either a neutral or emotional word. Faster responses when the probe appears in the location of the emotional stimulus indicates a bias towards the emotional stimulus. Outcome measures include: accuracy when probe is presented in position of negative stimuli (negative trial, congruent); accuracy when probe is presented in position of neutral stimuli (negative trial, incongruent); accuracy when probe is presented in position of positive stimuli (positive trial, congruent); accuracy when probe is presented in position of neutral stimuli (positive trial, incongruent); RT for negative congruent \& incongruent; RT for positive congruent \& incongruent; negative attentional bias; positive attentional bias.
Measured: Post-intervention (6 weeks)
Emotion Go/No-Go task
A go/no-go task where participants press the spacebar to respond to 'go' trials and withhold pressing the spacebar on 'no-go' trials, measuring inhibitory control and attention. This task contains 8 conditions which are presented in a random order: Fear Go, Neutral No-Go; Neutral Go, Fear No-Go; Happy Go, Neutral No-Go; Neutral Go, Happy No-Go; Sad Go, Neutral No-Go; Neutral Go, Sad No-Go; Angry Go, Neutral No-Go; Neutral Go, Angry No-Go. Outcome measures include hit rate (correctly responding to go trails), miss rate (1 - hit rate), overall commission error (pressing space on no-go), rejection rate (1-commission error), hit reaction time. Each of these outcome measures is also calculated per emotional condition.
Measured: Baseline
Emotion Go/No-Go task
A go/no-go task where participants press the spacebar to respond to 'go' trials and withhold pressing the spacebar on 'no-go' trials, measuring inhibitory control and attention. This task contains 8 conditions which are presented in a random order: Fear Go, Neutral No-Go; Neutral Go, Fear No-Go; Happy Go, Neutral No-Go; Neutral Go, Happy No-Go; Sad Go, Neutral No-Go; Neutral Go, Sad No-Go; Angry Go, Neutral No-Go; Neutral Go, Angry No-Go. Outcome measures include hit rate (correctly responding to go trails), miss rate (1 - hit rate), overall commission error (pressing space on no-go), rejection rate (1-commission error), hit reaction time. Each of these outcome measures is also calculated per emotional condition.
Measured: Post-intervention (6 weeks)
Gastrointestinal Symptoms Rating Scale (GSRS)
A 15-item questionnaire to ascertain whether participants experienced any gastrointestinal side effects of consuming either the prebiotic or placebo. Participants will also be asked whether the level of experience they report for each symptom is better than, worse than, or the same as prior to taking part in the trial
Measured: Post-intervention (6 weeks)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 May 2025
- Study start31 Mar 2025
- Primary completion17 Oct 2025
- Study completionFeb 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Mild-to-Moderate StressStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 55 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Reading
- Sponsor type
- University, hospital or other
- Collaborators
- Clasado Research Services Ltd
- Responsible party
- Principal investigator, Daniel Lamport, University of Reading
- Investigators
- Daniel Lamport, PhD, Principal investigator, University of ReadingPiril Hepsomali, Study director, University of ReadingClaire Williams, Study director, University of Reading
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06991023
- Sponsor's protocol ID
- UReading Prebiotics & Stress
- Acronym
- PEACE
- Status last verified
- Jan 2026
- First submitted
- 18 Mar 2025
- Last updated
- 8 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: All questionnaire, cognitive, and saliva data will be preserved and may be made available in anonymised form on a public repository such as the University of Reading Research Data Archive at the end of the project, in accordance with Open Science Principles.
Study at a glance
From the registry record, last updated by the sponsor on 8 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomised Controlled Trial Exploring the Effects of Prebiotics for Mental Strain and Physiological Markers of Stress in Healthy, Mild-to-Moderately Stressed Adults
- ClinicalTrials.gov ID
- NCT06991023
- Acronym / sponsor ID
- PEACE / UReading Prebiotics & Stress
- Conditions
- Mild-to-Moderate Stress
- Keywords
- Randomised Controlled Trial, Stress, Cortisol, Prebiotic
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 55 participants (estimated)
- Lead sponsor
- University of ReadingUniversity, hospital or other
- Collaborators
- Clasado Research Services Ltd
- Study start
- 31 Mar 2025 (actual)
- Primary completion
- 17 Oct 2025 (actual)
- Study completion
- Feb 2026 (estimated)
- First posted
- 25 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The levels of stress that we experience as a population are continuing to rise due to financial, social and work pressures, particularly in mid-life where additional factors such as family and career often compound these issues. When we experience high levels of stress for prolonged periods, this often has detrimental effects on our mental and physical wellbeing, leading to chronic illness and mental health disorders.
Prebiotics are non-digestible fibres found in food and supplements which promote the growth of beneficial bacteria that produce short-chain fatty acids (SCFAs). Research shows that prebiotics may be used as a lifestyle intervention to support individuals experiencing stress and help reduce physiological and psychological feelings of stress.
As such, this study will build on previous research and explore whether a prebiotic supplement (Bimuno®) has a beneficial effect on stress, mental health outcomes, and sleep in mild-to-moderately stressed adults. To address these questions, participants will take the prebiotic or a placebo for 6 weeks, and visit the University of Reading to complete some questionnaires and cognitive tests at the start and end of the trial. The investigators will also ask participants to collect saliva samples to see if the prebiotics influence cortisol levels, which are linked to stress.
Detailed description
The study employs a parallel groups, randomised, placebo-controlled design in 55 (allowing for 10% attrition) adults aged 25 - 40 experiencing mild-to-moderate stress. Information sheet, consent form, screening and collection of demographic data will be conducted via Redcap at the start of the study. Each participant will then attend 3 in-person sessions at the UoR Psychology department - 1 practice session, and 2 study visits 6 weeks apart. Between the study visits, participants will be required to consume a prebiotic supplement (Bimuno®) once a day at home, and collect saliva samples on 4 occasions.
Screening (all conducted via Redcap) All participants will read through the participant information sheet and sign the consent form before completing a health and lifestyle screening questionnaire to collect demographic data and ensure they meet the eligibility criteria. If eligible, subjects will then be invited to attend an in-person practice visit.
Practice visit The practice visit will be conducted in the Nutrition, Cognition and Health lab in the Psychology department, at any time of day (within working hours) to suit the participant. During this visit, the researcher will double-check participant eligibility and talk the subject through the full trial protocol. Participants will then complete the mood questionnaires and one practice round of the cognitive task (detailed in the study visit section below). This allows participants to see the type of questions they will be asked and ensure they're comfortable answering them, as well as ensure competency on the task before collecting data in the study visits. Finally, participants will be provided with two cycles worth of saliva sample kits and a demonstration on how collect their saliva samples.
Study visit(s) Subjects will consume a standardised breakfast of one slice of white toast and butter with water at home prior to arrival (or, if the participant does not routinely eat breakfast, they may arrive for the visits fasted). Study visits will be conducted in the Nutrition, Cognition and Health lab in the Psychology department, and participants will have the option to arrive anytime between 8am and 11am. This allows participants to complete their study visits before starting their work day if necessary, but also ensures that all sessions are complete before lunch removing the need to provide standardised lunch for participants. Start time of sessions will be kept consistent across visits within participants, as will the choice to have breakfast or not. During the study visits, participants will complete the following mood and sleep questionnaires in a fixed order using Redcap.
Following the questionnaires, participants will complete two emotional cognition tasks in order to explore how the prebiotic supplement might affect emotional processing. All measures will be administered via Inquisit.
At the end of the first study visit, subjects will be provided with their intervention sachets and two more cycles-worth of saliva kits to be used at the end of the study. At the end of the second visit, participants will be given the debrief sheet and emailed a payment form to complete. Both the prebiotic and the matched placebo are supplied by Clasado Research Services Ltd, Reading UK.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Prebiotic | Experimental | Dietary Supplement: Prebiotic (Bimuno®)The prebiotic supplement (Bimuno®) is a galactooligosaccharide (GOS) supplement derived from lactose which is publicly available and sold in the UK. Subjects will consume a daily dose of 2.75g GOS (3.65g total powder) which will be administered in sachets and consumed with breakfast by mixing into water, tea or coffee, or sprinkling on top of/mixing into food. |
| Placebo | Placebo comparator | Dietary Supplement: PlaceboThe matched placebo contains 3.65g sachets of maltodextrin, and is consumed in the same manner as the prebiotic. |
Who may qualify
- Ages
- 25 to 40 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Aged 25-40
- Meeting at least mildly stressed as per the stress subscale on the Depression, Anxiety and Stress Scale (DASS-42) (score of 15 or more)
Key exclusion criteria (13 listed)
- Antibiotics within 3 months of enrolment
- Habitual consumption of pre-, pro-, or synbiotics within 3 months of enrolment
- Diagnosis of a mental health disorder within 6 months of enrolment
- Use of antidepressant medication within 6 months of enrolment
- Smoking (defined as having smoked anytime within a month of enrolment
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Prebiotic (Bimuno®)The prebiotic supplement (Bimuno®) is a galactooligosaccharide (GOS) supplement derived from lactose which is publicly available and sold in the UK. Subjects will consume a daily dose of 2.75g GOS (3.65g total powder) which will be administered in sachets and consumed with breakfast by mixing into water, tea or coffee, or sprinkling on top of/mixing into food. | Dietary supplement | Prebiotic |
| PlaceboA matched placebo for the prebiotic intervention, containing 3.65g of maltodextrin. Consumed in the same manner as the prebiotics. | Dietary supplement | Placebo |
Primary outcome
Perceived Stress Scale (PSS)
Time frame: Baseline
The PSS is a widely used psychological instrument for measuring the perception of stress. Items were designed to tap how unpredictable, uncontrollable, and overloaded respondents find their lives. The scale also includes a number of direct queries about current levels of experienced stress. The questions in the PSS ask about feelings and thoughts during the last month. In each case, respondents are asked how often they felt a certain way using the following 5-point Likert scale: 0 = Never, 1 = Almost Never, 2 = Sometimes, 3 = Fairly Often, 4 = Very Often.
Perceived Stress Scale (PSS)
Time frame: Post-intervention (6 weeks)
The PSS is a widely used psychological instrument for measuring the perception of stress. Items were designed to tap how unpredictable, uncontrollable, and overloaded respondents find their lives. The scale also includes a number of direct queries about current levels of experienced stress. The questions in the PSS ask about feelings and thoughts during the last month. In each case, respondents are asked how often they felt a certain way using the following 5-point Likert scale: 0 = Never, 1 = Almost Never, 2 = Sometimes, 3 = Fairly Often, 4 = Very Often.
20 secondary outcomes
Positive and Negative Affect Schedule - expanded (PANAS-x)
Time frame: Baseline
Positive and Negative Affect Schedule - expanded (PANAS-x)
Time frame: 6 weeks
Patient Health Questionnaire-8 (PHQ-8)
Time frame: Baseline
Patient Health Questionnaire-8 (PHQ-8)
Time frame: Post-intervention (6 weeks)
General Anxiety Disorder-7 (GAD-7)
Time frame: Baseline
General Anxiety Disorder-7 (GAD-7)
Time frame: Post-intervention (6 weeks)
Pittsburgh Sleep Quality Index (PSQI)
Time frame: Baseline
Pittsburgh Sleep Quality Index (PSQI)
Time frame: Post-intervention (6 weeks)
Salivary Cortisol
Time frame: 1 day before baseline
Salivary Cortisol
Time frame: Baseline
Salivary Cortisol
Time frame: 1 day before post-intervention measures (6 weeks)
Salivary Cortisol
Time frame: Post-intervention (6 weeks)
Epic-Norfolk Food Frequency Questionnaire
Time frame: Baseline
FibreScreen
Time frame: Baseline
FibreScreen
Time frame: Post-intervention (6 weeks)
Emotion dot probe task
Time frame: Baseline
Emotion dot probe task
Time frame: Post-intervention (6 weeks)
Emotion Go/No-Go task
Time frame: Baseline
Emotion Go/No-Go task
Time frame: Post-intervention (6 weeks)
Gastrointestinal Symptoms Rating Scale (GSRS)
Time frame: Post-intervention (6 weeks)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Jan 2026.
- Individual participant dataSharing planned: Yes. All questionnaire, cognitive, and saliva data will be preserved and may be made available in anonymised form on a public repository such as the University of Reading Research Data Archive at the end of the project, in accordance with Open Science Principles.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Daniel Lamport, PhD principal investigator
University of Reading
Piril Hepsomali study director
University of Reading
Claire Williams study director
University of Reading
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Prebiotic (Bimuno®) in people with Mild-to-Moderate Stress, run by University of Reading at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 8 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Perceived Stress Scale (PSS) (time frame: Baseline). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Jan 2026.