Prebiotic Effects on Anxiety, Cortisol, and Emotional Processing in Mild-to-Moderately Stressed Adults

NCT06991023 | Active Not Recruiting

• 1 other identifier: UReading Prebiotics & Stress
• Study Type: interventional
• Target: 55
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Mild-to-Moderate Stress

Keywords

Randomised Controlled Trial; Stress; Cortisol; Prebiotic

Outcome Measures

Primary Outcomes (2)

• 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.

  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.

  Post-intervention (6 weeks)

Secondary Outcomes (20)

• Positive and Negative Affect Schedule - expanded (PANAS-x)

  Baseline

• Positive and Negative Affect Schedule - expanded (PANAS-x)

  6 weeks

• Patient Health Questionnaire-8 (PHQ-8)

  Baseline

• Patient Health Questionnaire-8 (PHQ-8)

  Post-intervention (6 weeks)

• General Anxiety Disorder-7 (GAD-7)

  Baseline

Study Arms (2)

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.

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.

Dietary Supplement: Placebo

Interventions

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.

Prebiotic

Placebo DIETARY_SUPPLEMENT

A matched placebo for the prebiotic intervention, containing 3.65g of maltodextrin. Consumed in the same manner as the prebiotics.

Placebo

Eligibility Criteria

• Age: 25 Years - 40 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• 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)

You may not qualify if:

• 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
• 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

Sponsors & Collaborators

• University of Reading: lead
• Clasado Research Services Ltd: collaborator

Study Sites (1)

Nutrition, Cognition & Health Lab, School of Psychology and Clinical Language Sciences, University of Reading

Reading, Berkshire, RG6 6ES, United Kingdom

Location

MeSH Terms

Interventions

Prebiotics

Intervention Hierarchy (Ancestors)

Dietary Fiber; Dietary Carbohydrates; Carbohydrates; Polysaccharides, Bacterial; Polysaccharides; Food; Diet, Food, and Nutrition; Physiological Phenomena; Dietary Supplements; Food and Beverages

Study Officials

• Daniel Lamport, PhD

  University of Reading

  PRINCIPAL INVESTIGATOR

• Piril Hepsomali

  University of Reading

  STUDY DIRECTOR

• Claire Williams

  University of Reading

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: March 18, 2025
• First Posted: May 25, 2025
• Study Start: March 31, 2025
• Primary Completion: October 17, 2025
• Study Completion: February 1, 2026
• Last Updated: January 8, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will share

Locations

GB (1)