Probiotics in Wellbeing

NCT07840066 | Active Not Recruiting DMC

• 2 other identifiers: 26/20UKRI775
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

This study will investigate whether taking a probiotic supplement every day for 12 weeks can reduce low-level inflammation and improve wellbeing in generally healthy adults. Forty adults will be randomly assigned to receive either a probiotic capsule or a placebo capsule that looks the same but does not contain probiotic bacteria. Neither the participants nor the researchers involved in the study will know which treatment each participant receives until the study is completed. Participants will attend a study visit before starting the supplement and another visit after 12 weeks, with a remote check midway through the study. Blood samples will be collected to measure markers of inflammation and stress. Stool samples will be collected to assess the gut microbiota and substances produced by gut bacteria. Urine samples will also be collected to measure metabolites, which are small molecules produced by normal processes in the body and by interactions between the body, diet and gut microbiota. Participants will also complete questionnaires about wellbeing, mood, anxiety, quality of life and memory. The main aim of the study is to determine whether the probiotic reduces a combined measure of several markers of inflammation compared with placebo. The study will also explore whether changes in inflammation are associated with changes in wellbeing and memory, and whether these effects are accompanied by changes in the gut microbiota or in metabolic profiles measured in stool and urine. The results will help researchers understand how probiotics may influence communication between the gut, immune system and brain, and will provide information to help design a larger clinical trial.

Conditions

Healthy Participants

Outcome Measures

Primary Outcomes (1)

• Change in standardised pro-inflammatory biomarker composite

  Change from baseline to Week 12 in a pre-specified pro-inflammatory composite comprising IL-6, TNF-α, IL-1β, IL-8, IFN-γ and high-sensitivity C-reactive protein (hsCRP). Each biomarker will be standardised relative to its baseline distribution and the composite calculated as the mean of direction-consistent z-scores. This is a study-defined continuous composite rather than a bounded clinical scale; therefore, it has no fixed theoretical minimum or maximum. Higher composite values indicate greater systemic inflammatory activity, and a negative change from baseline indicates a reduction in inflammatory activity. The between-group change will be compared between the probiotic and placebo groups.

  Baseline and Week 12

Secondary Outcomes (8)

• Change in plasma IL-10 concentration

  Baseline and Week 12

• Change in serum cortisol concentration

  Baseline and Week 12

• Change in 12-Item Short Form Health Survey Mental Component Summary score

  Baseline and Week 12

• Change in 12-Item Short Form Health Survey Physical Component Summary score

  Baseline and Week 12

• Change in Patient Health Questionnaire-9 total score

  Baseline and Week 12

Other Outcomes (8)

• Exploratory differential abundance of faecal bacterial ASVs

  Baseline and week 12

• Faecal bacterial beta diversity assessed by Bray-Curtis dissimilarity

  Baseline and Week 12

• Change in faecal bacterial alpha diversity assessed by Shannon diversity index

  Baseline and Week 12

Study Arms (2)

Vegan capsules filled with potato starch only.

PLACEBO COMPARATOR

Daily oral administration of one matched placebo capsule for 12 weeks. The placebo contains potato starch in place of the probiotic bacterial mass and is matched to the active intervention in capsule shell, appearance and fill weight. Participants will take one capsule daily with water for 12 weeks, beginning the day after baseline sampling.

Dietary Supplement: Daily oral administration of one matched placebo capsule for 12 weeks. The placebo contains potato starch in place of the probiotic bacterial mass and is matched to the active intervention.

Probiotic supplement

EXPERIMENTAL

Daily oral administration of one capsule of a multi-strain probiotic supplement (Optibac "Every Day") for 12 weeks. Each daily dose provides 5 × 10⁹ CFU and contains Lactobacillus rhamnosus Rosell-11 (R0011), Lactobacillus acidophilus/helveticus Rosell-52 (R0052), Bifidobacterium longum Rosell-175 (R0175), Bifidobacterium breve Rosell-70 (R0070), Bifidobacterium bifidum Rosell-71 (R0071), and Lactococcus lactis Rosell-1058 (R1058), together with fructooligosaccharides (FOS). Participants will take one capsule daily with water for 12 weeks, beginning the day after baseline sampling.

Dietary Supplement: Probiotic Supplementation (Lactobacillus plantarum)

Interventions

Probiotic Supplementation (Lactobacillus plantarum) DIETARY_SUPPLEMENT

Daily oral administration of one capsule of a multi-strain probiotic supplement (Optibac "Every Day") for 12 weeks. Each daily dose provides 5 × 10⁹ CFU and contains Lactobacillus rhamnosus Rosell-11 (R0011), Lactobacillus acidophilus/helveticus Rosell-52 (R0052), Bifidobacterium longum Rosell-175 (R0175), Bifidobacterium breve Rosell-70 (R0070), Bifidobacterium bifidum Rosell-71 (R0071), and Lactococcus lactis Rosell-1058 (R1058), together with fructooligosaccharides (FOS). Participants will take one capsule daily with water for 12 weeks, beginning the day after baseline sampling.

Also known as: Optibac Every Day Probiotic

Probiotic supplement

Daily oral administration of one matched placebo capsule for 12 weeks. The placebo contains potato starch in place of the probiotic bacterial mass and is matched to the active intervention. DIETARY_SUPPLEMENT

Daily oral administration of one matched placebo capsule for 12 weeks. The placebo contains potato starch in place of the probiotic bacterial mass and is matched to the active intervention in capsule shell, appearance and fill weight. Participants will take one capsule daily with water for 12 weeks, beginning the day after baseline sampling.

Vegan capsules filled with potato starch only.

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Generally healthy adults
• Aged 18 to 60 years
• Body mass index (BMI) 18.5 to 30 kg/m²

You may not qualify if:

• Antibiotic use within the previous 3 months
• Chronic gastrointestinal disorders
• Chronic immune disorders
• Current probiotic or prebiotic use
• Current use of immunomodulatory medication
• Pregnancy or lactation
• Relevant allergies

Sponsors & Collaborators

• University of Reading: lead
• Biotechnology and Biological Sciences Research Council: collaborator
• Wren Laboratories LLC: collaborator

Study Sites (1)

The University of Reading

Reading, Berkshire, RG66DX, United Kingdom

Location

Study Design

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

Model Details: Two-arm, randomised, double-blind, placebo-controlled, parallel-group study. Participants will be allocated 1:1 to receive either a daily multi-strain probiotic supplement or matched placebo for 12 weeks.

Study Record Dates

• First Submitted: September 14, 2026
• First Posted: September 24, 2026
• Study Start: September 1, 2026
• Primary Completion (Estimated): August 1, 2027
• Study Completion (Estimated): September 1, 2027
• Last Updated: September 24, 2026

Record last verified: 2026-09

Locations

GB (1)