HealthyNCT05517928
A Study to Evaluate the Impact of Lactobacillus Rhamnosus GG on Proton Pump Inhibitor-Induced Gut Dysbiosis
A study testing Omeprazole and Lactobacillus rhamnosus GG in people with Healthy, run by Mayo Clinic at 1 site in United States.
Trial summary
The purpose of this study is to investigate the impact of the probiotic Lactobacillus rhamnosus (LGG) on proton pump inhibitor (PPI)-induced changes to the microbes that live in the gastrointestinal tract and are passed out in the stool. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- Omeprazole and Lactobacillus rhamnosus GG
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- 1 siteUnited States
- Study dates
- 3 Mar 2023to Dec 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 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Individuals on an unrestricted regular diet with no dietary restrictions (vegan, low FODMAP, gluten free, dairy-free etc) or other fad diets (e.g., keto, intermittent fasting, etc.).
- Healthy subjects will be screened for current or chronic GI symptoms using a 16-item questionnaire.
- Only those with an absence of symptoms will eligible to participate.
Who cannot join
- For healthy volunteers, will include prior surgery altering the esophagus, stomach, and intestine (except appendectomy).
- Chronic daily use of medications affecting GI secretion or motor function.
- The presence of any GI-motility affecting systemic diseases or untreated psychiatric disease.
- Pregnancy.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Mayo Clinic Arizona
Scottsdale, Arizona, 85259
Yonas Berhe, B.S, 480-301-6315, berhe.yonas@mayo.edu
About this study
Official title: Exploratory Study of the Impact of Lactobacillus Rhamnosus GG on Proton Pump Inhibitor-Induced Gut Dysbiosis
The purpose of this study is to investigate the impact of the probiotic Lactobacillus rhamnosus (LGG) on proton pump inhibitor (PPI)-induced changes to the microbes that live in the gastrointestinal tract and are passed out in the stool. PPI medicines reduce stomach acid and are commonly used to treat acid reflux disease.
- Conditions
- Healthy
- Being tested
- Omeprazole, Lactobacillus rhamnosus GG, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
OmeprazoleDrug
40 MG oral capsules daily
Lactobacillus rhamnosus GGDietary supplement
Given as Culturelle Digestive Probiotic in the form of oral capsules daily
PlaceboDrug
Oral capsules daily that look exactly like the study drug, but contains to active ingredient
| Study group | Role | What they receive |
|---|---|---|
| Lactobacillus rhamnosus GG Group | Experimental | Subjects will receive omeprazole daily for 56 days. After 28 days, subjects will receive Lactobacillus rhamnosus GG two capsules daily taken with a meal. Receives: Drug: Omeprazole; Dietary Supplement: Lactobacillus rhamnosus GG |
| Placebo Group | Placebo comparator | Subjects will receive omeprazole daily for 56 days. After 28 days, subjects will receive placebo two capsules daily taken with a meal. Receives: Drug: Omeprazole; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Observed Operational Taxonomic Unit (OTU) diversity.
Observed OTU counts in each stool sample will be tested at varying cutoffs by determining the number of OTUs per sample.
Measured: Baseline, Day 56
Secondary outcomes (4)
Adverse Events
Number of participants to report adverse events.
Measured: 60 days
Changes in Shannon diversity index.
Observed Shannon diversity index count between PPI and placebo group compare to PPI and probiotic group.
Measured: Baseline, Day 56
Changes in enrichment according to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways.
Observed changes according to KEGG pathways as compared between PPI and placebo versus PPI and probiotic groups.
Measured: Baseline, Day 56
Changes in taxa units.
Observed changes in taxonomic classifications as compared in PPI and placebo groups versus PPI and probiotic groups.
Measured: Baseline, Day 56
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Aug 2022
- Study start3 Mar 2023
- Primary completionDec 2026 (estimated)
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by Mayo ClinicThe sponsor's other registered studies.
- 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
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mayo Clinic
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, John K. DiBaise, Mayo Clinic
- Investigators
- John DiBaise, MD, Principal investigator, Mayo Clinic
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05517928
- Sponsor's protocol ID
- 21-007621
- Status last verified
- Jan 2026
- First submitted
- 24 Aug 2022
- Last updated
- 8 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
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
- Exploratory Study of the Impact of Lactobacillus Rhamnosus GG on Proton Pump Inhibitor-Induced Gut Dysbiosis
- ClinicalTrials.gov ID
- NCT05517928
- Acronym / sponsor ID
- 21-007621
- Conditions
- Healthy
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Mayo ClinicUniversity, hospital or other
- Study start
- 3 Mar 2023 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Dec 2026 (estimated)
- First posted
- 26 Aug 2022 (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 purpose of this study is to investigate the impact of the probiotic Lactobacillus rhamnosus (LGG) on proton pump inhibitor (PPI)-induced changes to the microbes that live in the gastrointestinal tract and are passed out in the stool. PPI medicines reduce stomach acid and are commonly used to treat acid reflux disease.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Lactobacillus rhamnosus GG Group | Experimental | Drug: Omeprazole, Dietary Supplement: Lactobacillus rhamnosus GGSubjects will receive omeprazole daily for 56 days. After 28 days, subjects will receive Lactobacillus rhamnosus GG two capsules daily taken with a meal. |
| Placebo Group | Placebo comparator | Drug: Omeprazole, Drug: PlaceboSubjects will receive omeprazole daily for 56 days. After 28 days, subjects will receive placebo two capsules daily taken with a meal. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Individuals on an unrestricted regular diet with no dietary restrictions (vegan, low FODMAP, gluten free, dairy-free etc) or other fad diets (e.g., keto, intermittent fasting, etc.).
- Healthy subjects will be screened for current or chronic GI symptoms using a 16-item questionnaire.
- Only those with an absence of symptoms will eligible to participate.
Key exclusion criteria (4 listed)
- For healthy volunteers, will include prior surgery altering the esophagus, stomach, and intestine (except appendectomy).
- Chronic daily use of medications affecting GI secretion or motor function.
- The presence of any GI-motility affecting systemic diseases or untreated psychiatric disease.
- Pregnancy.
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 |
|---|---|---|
| Omeprazole40 MG oral capsules daily | Drug | Lactobacillus rhamnosus GG Group, Placebo Group |
| Lactobacillus rhamnosus GGGiven as Culturelle Digestive Probiotic in the form of oral capsules daily | Dietary supplement | Lactobacillus rhamnosus GG Group |
| PlaceboOral capsules daily that look exactly like the study drug, but contains to active ingredient | Drug | Placebo Group |
Primary outcome
Change in Observed Operational Taxonomic Unit (OTU) diversity.
Time frame: Baseline, Day 56
Observed OTU counts in each stool sample will be tested at varying cutoffs by determining the number of OTUs per sample.
4 secondary outcomes
Adverse Events
Time frame: 60 days
Changes in Shannon diversity index.
Time frame: Baseline, Day 56
Changes in enrichment according to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways.
Time frame: Baseline, Day 56
Changes in taxa units.
Time frame: Baseline, Day 56
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.
- Mayo Clinic Clinical Trial WebsiteLink provided by the sponsor.
- Individual participant dataSharing planned: No
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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.
John DiBaise, MD principal investigator
Mayo Clinic
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Omeprazole and Lactobacillus rhamnosus GG in people with Healthy, run by Mayo Clinic at 1 site in United States.
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 3 inclusion and 4 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: looking for participants now, 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 States. 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?
Contact Alexandria Ramirez (4805741853, ramirez.alexandria@mayo.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Observed Operational Taxonomic Unit (OTU) diversity. (time frame: Baseline, Day 56). 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.