Probiotic in Fruit Snack (Probiotics)

June 25, 2026 updated by: Carel le Roux, University College Dublin

A Physiological Study of a Fruit Snack Containing Probiotics

The aim of this study is to investigate whether a fruit snack containing probiotic ''Lactobacillus rhamnosus'' can survive and establish itself more effectively in the gut when it is protected inside a natural plant-protein coating and delivered in a fruit snack.

Lactobacillus rhamnosus is a beneficial bacterium that may support gut health and influence communication between the gut and the brain. In this study, we will examine how the probiotic affects the gut microbiome (the community of bacteria that naturally live in the gut).

We are recruiting 25 healthy men and women aged 25-65 years with a body mass index (BMI) between 18.5 and 31.9 kg/m². Participants will be randomly assigned to receive either:

A) Fruit snack containing encapsulated Lactobacillus rhamnosus probiotics, or a similar fruit snack that does not contain probiotics (placebo).

Neither participants nor researchers (blinded) will know which snack is being provided during the study.

Participants will attend four study visits over approximately 10 weeks (70 days): at the baseline visit Day 0 and again at Days 28, Day 42, and Day 70. A blood and stool samples will be collected at the beginning of the study, and samples will be used to assess changes in the gut microbiome over time.

The findings from this study will help us better understand how targeted delivery of probiotics to the gut may influence the gut microbiome and support digestive health.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

The gut microbiota plays an important role in human health through interactions with the gastrointestinal, immune, endocrine, and nervous systems. Increasing evidence suggests that the gut microbiota influences gastrointestinal and brain function through the microbiota-gut-brain axis, a bidirectional communication network linking the gastrointestinal tract and the central nervous system. Alterations in gut microbial composition have been associated with aging-related physiological changes, gastrointestinal function, inflammation, cognition, and mood.

Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. However, the effectiveness of probiotic supplementation depends on the ability of viable microorganisms to survive food processing, storage, gastric acidity, and gastrointestinal transit before reaching their target site in the intestine. Consequently, strategies that improve probiotic survival and targeted delivery may enhance intestinal colonisation and biological activity within the gastrointestinal tract.

Microencapsulation is a promising approach for protecting probiotic bacteria during manufacturing, storage, and passage through the upper gastrointestinal tract. Encapsulation within a protective plant protein matrix may increase delivery of viable probiotic cells to the intestine by reducing exposure to gastric acid and digestive enzymes. The investigational product used in this study contains Lactobacillus rhamnosus microencapsulated using a plant protein-based delivery system and incorporated into a fruit snack.

The primary objective of this study is to determine whether daily consumption of a fruit snack containing microencapsulated Lactobacillus rhamnosus increases intestinal colonisation compared with a matched fruit snack without probiotics. Colonisation will be assessed by measuring the abundance of Lactobacillus rhamnosus in stool samples.

Secondary objectives include evaluating the effects of the intervention on gut microbiome composition and diversity, and exploring changes in markers related to gastrointestinal function and microbiota-gut-brain axis physiology.

This study is a randomised, double-blind, placebo-controlled crossover trial. Participants will complete two 28-day intervention periods separated by a 14-day washout period. Participants will receive both study interventions in a random order: (1) a fruit snack containing microencapsulated Lactobacillus rhamnosus and (2) a matched fruit snack without probiotics.

Participants will consume one 28-g serving of the assigned fruit snack each day during each intervention period. The probiotic snack contains Lactobacillus rhamnosus at a concentration of 2 × 10⁹ colony-forming units (CFU) per gram, providing a total daily dose of approximately 5.6 × 10¹⁰ CFU (56 billion CFU/day). Stool samples will be collected at predefined study visits to assess probiotic colonisation and changes in gut microbiome composition.

This study will provide evidence regarding the effectiveness of plant protein-based microencapsulation technology for probiotic delivery and improve understanding of the impact of targeted probiotic supplementation on intestinal colonisation and the human gut microbiome.

Study Type

Interventional

Enrollment (Actual)

25

Phase

  • Not Applicable

Contacts and Locations

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

Study Locations

  • Ireland
    • Dublin 04
      • Dublin, Dublin 04, Ireland, D04 T6F4
        • Clinical Research Centre, St. Vincent's University Hospital

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:

  • Signed informed consent prior to any study-related procedure Age 25-65 years-old
  • 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:

  • Smoking
  • Substance abuse
  • Pregnancy and lactaction
  • 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)
  • People with intellectual disabilities.
  • History of complicated gastrointestinal surgery
  • Diagnosed 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 principle 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.

Justification: it is necessary to exclude participation from individuals with smoking or substance abuse as that may compromise the physiological gut response.

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Experimental Arm 1
Participants receive the fruit snack containing microencapsulated Lactobacillus rhamnosus for 28 days, followed by a 14-day washout period and then the placebo fruit snack for 28 days.
Dietary supplement: Microencapsulated Lactobacillus rhamnosus Fruit Snack

Participants consume one 28-gram fruit snack daily containing microencapsulated Lactobacillus rhamnosus at a concentration of 2 × 10⁹ CFU/g, providing a total daily dose of approximately 5.6 × 10¹⁰ CFU (56 billion CFU/day). The probiotic is delivered in a plant protein-based microencapsulation matrix designed to enhance survival through the gastrointestinal tract and support delivery to the intestine.

Arm 1: Probiotic then Placebo intervention.

Other Names:
  • Probiotic fruit snack
  • Lactobacillus rhamnosus encapsulated snack
Placebo Comparator: Experimental Arm 2
Participants receive the placebo fruit snack for 28 days, followed by a 14-day washout period and then the fruit snack containing microencapsulated Lactobacillus rhamnosus for 28 days.
Dietary supplement: Placebo Fruit Snack

Participants daily consume one 28-gram fruit snack daily that is identical in appearance, taste, and texture to the active product but does not contain probiotic bacteria. The placebo snack contains the same base ingredients without Lactobacillus rhamnosus.

Arm 2: Placebo then Probiotic intervention.

Other Names:
  • Non-probiotics fruit snack
  • control fruit snack

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in faecal abundance of Lactobacillus rhamnosus
Time Frame: Baseline, Day 28, Day 42 (end of washout), Day 70 (end of second intervention period).
Stool samples will be collected at four time points: baseline (pre-intervention), end of the first 28-day intervention period, end of the washout period (Day 42), and end of the second 28-day intervention period (Day 70). The abundance of Lactobacillus rhamnosus will be quantified using strain-specific molecular and/or sequencing-based microbiome analysis methods. Changes in abundance will be compared between probiotic and placebo intervention periods in a crossover design.
Baseline, Day 28, Day 42 (end of washout), Day 70 (end of second intervention period).

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serum serotonin concentration
Time Frame: Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Serum serotonin levels will be measured from blood samples to assess systemic neuroactive changes.
Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Serum brain-derived neurotrophic factor (BDNF)
Time Frame: Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Serum BDNF levels measured as a marker of neurotrophic activity and brain-gut axis signalling.
Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Inflammatory cytokine (IL-6) concentration
Time Frame: Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Plasma concentrations of IL-6 will be measured as indicators of systemic inflammatory and anti-inflammatory responses.
Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Inflammatory cytokine (IL-10) concentration
Time Frame: Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Plasma concentrations IL-10 will be measured as indicators of systemic inflammatory and anti-inflammatory responses.
Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Inflammatory cytokine (TNF-alpha)
Time Frame: Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Plasma concentrations TNF-α will be measured as indicators of systemic inflammatory and anti-inflammatory responses.
Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Intestinal fatty acid-binding protein (I-FABP)
Time Frame: Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)
Plasma I-FABP levels will be measured as a marker of intestinal epithelial integrity and permeability.
Baseline, end of Period 1 (Day 28), end of washout (Day 42), and end of Period 2 (Day 70)

Collaborators and Investigators

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

Sponsor

University College Dublin

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

Helpful Links

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 (Actual)

January 18, 2026

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

January 1, 2027

Study Registration Dates

First Submitted

June 25, 2026

First Submitted That Met QC Criteria

June 25, 2026

First Posted (Actual)

July 1, 2026

Study Record Updates

Last Update Posted (Actual)

July 1, 2026

Last Update Submitted That Met QC Criteria

June 25, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RS24-010

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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