Encapsulated Probiotics & Gut Microbiota (Probiotics)

May 5, 2026 updated by: University College Dublin

A Physiological Study of a Fermented Yogurt Drink Containing Probiotics

The aim of this study is to determine whether encapsulation of probiotic bacteria using natural plant protein can enhance bacterial colonisation. Lactobacillus rhamnosus is an ideal strain for the intervention, as it has been shown to affect overall gut health, gut-brain axis, and brain function.

Twenty-five participants aged 25 to 65 years will be recruited and assessed on four occasions to compare the blood and faecal effects of a 28-day ingestion of a yoghurt beverage with and without the probiotic strain of interest. The study window will be 70+/13 days.

The current study will provide important information on the physiological function of probiotics in the small bowel. Understanding the underlying physiological effects of targeted probiotic delivery to the intestine and the impact on the microbiome is important for health outcomes.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The investigators plan to assess the gut microbiome and changes in probiotic diversity at the end of a course of a beverage containing encapsulated Lacticaseibacillus rhamnosus, compared to those at the end of a course of the same beverage without probiotics.

This is a randomised, double-blinded, placebo-controlled crossover study. Twenty-five healthy men and women with a body mass index (BMI) between 18.5-31.9 kg/m2, aged 25-65 years, will be recruited and randomised to a commercial fermented (yoghurt) drink containing a) encapsulated probiotics consisting of Lacticaseibacillus rhamnosus, or b) a non-probiotic fermented (yoghurt) dairy drink (control). The number of participants includes a 10% drop-out rate.

Each participant will be studied on four occasions in random order following a crossover design. Each will receive a 200 ml beverage containing yoghurt per day for 28 days, either a) fortified with 1 billion probiotics contained in pea protein capsules or b) the control beverage (same yoghurt without probiotic). Faecal samples will be collected on four occasions: at baseline, and at 28, 42 and 70 days after baseline.

The current study will provide important information on the physiological function of probiotics in metabolic and inflammatory biochemical parameters, as well as in their capacity to colonise the gastrointestinal tract.

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Capacity to obtain and sign informed consent before any study-related procedure
  • BMI range 18.5-31.9 kg/m2
  • Willing to abstain from regular consumption of probiotic supplements or food products containing probiotic bacteria (including fermented food and beverages).
  • Willing to abstain from regular consumption of supplements and medications known to alter gastrointestinal function or inflammatory status during the study.

Exclusion Criteria:

Participants who meet any of the following criteria will be excluded:

  • Smoking
  • Substance abuse
  • Pregnancy
  • Diagnosis of type 1 and/or type 2 diabetes
  • Current (or within the last 4 weeks prior to study start) use of probiotic supplementation.
  • Immobile (defined as the inability to participate in all study-related procedures)
  • History of complicated gastrointestinal surgery
  • Diagnosed with inflammatory bowel disease (IBD)
  • Current diagnosis of psychiatric disease/s or syndromes
  • Current diagnosis of neurodegenerative disease
  • Systemic use of antibiotics and/or steroid medication in the last 4 months prior to inclusion
  • Use of any non-steroidal anti-inflammatory drug (NSAID) more than 3 times a week for the last 2 months
  • Consumption of any NSAID within 7 days of study start
  • Any condition which could substantially interfere with intestinal barrier function (e.g. gluten sensitivity, lactose intolerance, celiac disease, IBS, IBD) or in any other way with the outcome of the study, as decided by the principal investigator's discretion
  • Regular smoking, use of snuff, nicotine, cannabidiol narcotics/supplements, or e-cigarette use
  • Drinking more than 9 standard cups of alcohol per week and/or more than 3 standard cups of alcohol per occasion
  • Regular use, for more than three times a week for the last 2 months and/or 7 days prior to inclusion, of medications which, according to the principal investigator, can have an anti-inflammatory effect or affect in any way the intestinal barrier function or have an impact on the study analysis (such as laxatives, anti-diarrheal, anti-cholinergic, etc.)
  • After being included in the study, starting any medication or treatment that could potentially influence the study participation and/or study analysis.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Probiotic drink
Encapsulated Lacticaseibacillus rhamnosus in 200 ml Yogurt drink
Biological: probiotic containing L.rhamnosus R0011 strain
Twenty-five participants will be studied on four occasions in random order and in a crossover design. Subjects will receive a daily dose of 200 ml on two different occasions for 28 days, a commercial dairy drink fortified with 1Billion probiotics in the pea protein capsules. Feacal samples will be collected on four occasions: at baseline, 28 days after baseline, 42 days and 70 days after baseline.
Placebo Comparator: Placebo drink
200 ml yogurt drink
Dietary supplement: 200 ml yogurt drink
Twenty-five participants will be studied on four occasions in random order and in a crossover design. Subjects will receive a daily dose 200 ml on two different occasions for 28 days, a commercial dairy drink (no probiotics). Feacal samples will be collected on four occasions: at baseline, 28 days after baseline, 42 days and 70 days after baseline.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Colonisation
Time Frame: 28 days
Faecal abundance of Lactobacillus rhamnosus after probiotic consumption measured through shotgun metagenomics -libraries with Illumina Nextera XT, sequenced 150 bp paired-end on NextSeq 2000. Negative + positive controls will be processed alongside study samples with around 15M paired reads/sample after quality controls.
28 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University College Dublin

Investigators

  • Principal Investigator: Carel Le Roux, PhD, St Vincent's University Hospital, Ireland

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

April 1, 2026

Primary Completion (Estimated)

June 1, 2026

Study Completion (Estimated)

August 1, 2026

Study Registration Dates

First Submitted

February 10, 2026

First Submitted That Met QC Criteria

February 24, 2026

First Posted (Actual)

February 27, 2026

Study Record Updates

Last Update Posted (Actual)

May 8, 2026

Last Update Submitted That Met QC Criteria

May 5, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • REF No. RS26-013

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

This study will be carried out in a single center. Therefore, fecal samples sent for microbiota analysis and data for statistical analyses will be identified by numbers allocated in the protocol and not contain identifiable information.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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