SIBOEarly Phase 1NCT04627727
Effect of a Low FODMAP Diet on SIBO Breath Test Positivity
A Early Phase 1 study testing low FODMAP diet in people with SIBO, run by Beth Israel Deaconess Medical Center at 1 site in United States.
Trial summary
Bloating is the most common symptom associated with disorders of brain-gut interaction (i.e., functional bowel disorders) such as irritable bowel syndrome, a disorder characterized by abdominal pain and altered bowel habits which affects up to 11% of world population. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- SIBO
- What is being tested?
- low FODMAP diet
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 14 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Nov 2020to 15 Dec 2024
- Phase
- Early Phase 1
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Aged 18-65 years at the time of screening
- Meet Rome IV criteria for functional bloating
- IBS-SSS score of at 176 (0-500)
- SIBO positive
Who cannot join
- individuals already on a LFD or other dietary restriction such as gluten free diet within the past 6 months
- individuals with peanut, soy, or seafood allergies or insulin-dependent diabetes
- known history of celiac disease, inflammatory bowel disease or microscopic colitis
- prior small bowel or colonic surgery or cholecystectomy
- pregnant patients
- antibiotics, excluding topical, in the past 3 months
Trial locations and contacts
1 site in 1 country.
United States1 site
Beth Israel Deaconess Medical Center
Boston, Massachusetts, 02215
About this study
Bloating is the most common symptom associated with disorders of brain-gut interaction (i.e., functional bowel disorders) such as irritable bowel syndrome, a disorder characterized by abdominal pain and altered bowel habits which affects up to 11% of world population. A common cause of bloating is small intestinal bacterial overgrowth (SIBO), a condition defined by excessive and/or abnormal type of bacteria in the small bowel. The potential role of SIBO for irritable bowel syndrome (IBS) was initially proposed by Pimentel et al. Using lactulose breath tests (LBTs), 78% of patients with IBS were also diagnosed with SIBO. After antibiotic therapy, 48% of patients no longer met the Rome criteria for IBS. A recent systematic review and meta-analysis concluded that the prevalence of SIBO is increased in IBS.
Read the detailed description
Despite the clinical efficacy of LFD in improving symptoms of IBS-D, its mechanism of action is not clear. Recently, Zhou et al have shown FODMAPs induce colonic tight junction dysfunction and visceral hypersensitivity in rat models, both of which are reversible when rats were fed an LFD. They further showed that this effect of FODMAPs is mediated by microbial dysbiosis and elevated fecal lipopolysaccharide level. However, studies evaluating the effect of LFD on colonic permeability of humans are lacking. Studies have shown significant differences in intra-individual luminal and mucosal microbiome of patients with functional gastrointestinal disorders as well as an increase in Prevotella abundance in IBS patients with SIBO as compared with IBS patients without SIBO. Thus, the exact effect of FODMAP on intestinal permeability and mucosal microbiome in humans is not clear and needs further evaluation.
- Conditions
- SIBO
- Being tested
- low FODMAP diet
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
low FODMAP dietOther
low FODMAP diet
| Study group | Role | What they receive |
|---|---|---|
| low FODMAP diet | Experimental | Consenting patients fulfilling the inclusion and exclusion criteria will undergo a 7-day screening period to assess baseline symptoms and then go on a 4-week low FODMAP diet Receives: Other: low FODMAP diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
SIBO Diagnosis
Number of Participants with Negative and Positive SIBO
Measured: four weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Nov 2020
- Study start15 Nov 2020
- Primary completion15 Dec 2024
- Study completion15 Dec 2024
Why it stopped: Early termination due to lack of funds, staffing
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for SIBOStudies of the same condition, open and under way.
- More trials run by Beth Israel Deaconess Medical CenterThe 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
- Early Phase 1
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 14 participants (actual)
Sponsor and investigators
- Lead sponsor
- Beth Israel Deaconess Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Judy Nee, Beth Israel Deaconess Medical Center
- Investigators
- Anthony Lembo, M.D, Principal investigator, Beth Israel Deaconess Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04627727
- Sponsor's protocol ID
- 2020P000622
- Status last verified
- Jul 2025
- First submitted
- 30 Oct 2020
- Last updated
- 4 Jul 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Lemos MPC, Zucoloto TG, Oliveira MC, de Oliveira GLV. Dysbiosis and Gut Microbiota Modulation in Systemic Sclerosis. J Clin Rheumatol. 2022 Mar 1;28(2):e568-e573. doi: 10.1097/RHU.0000000000001748.
PubMed 34030162
Study at a glance
From the registry record, last updated by the sponsor on 4 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of a Low FODMAP Diet on SIBO Breath Test Positivity
- ClinicalTrials.gov ID
- NCT04627727
- Acronym / sponsor ID
- 2020P000622
- Conditions
- SIBO
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Early termination due to lack of funds, staffing
- Enrolment
- 14 participants (actual)
- Lead sponsor
- Beth Israel Deaconess Medical CenterUniversity, hospital or other
- Study start
- 15 Nov 2020 (actual)
- Primary completion
- 15 Dec 2024 (actual)
- Study completion
- 15 Dec 2024 (actual)
- First posted
- 13 Nov 2020 (actual)
- Results
- Posted 4 Jul 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Bloating is the most common symptom associated with disorders of brain-gut interaction (i.e., functional bowel disorders) such as irritable bowel syndrome, a disorder characterized by abdominal pain and altered bowel habits which affects up to 11% of world population. A common cause of bloating is small intestinal bacterial overgrowth (SIBO), a condition defined by excessive and/or abnormal type of bacteria in the small bowel. The potential role of SIBO for irritable bowel syndrome (IBS) was initially proposed by Pimentel et al. Using lactulose breath tests (LBTs), 78% of patients with IBS were also diagnosed with SIBO. After antibiotic therapy, 48% of patients no longer met the Rome criteria for IBS. A recent systematic review and meta-analysis concluded that the prevalence of SIBO is increased in IBS.
Detailed description
Despite the clinical efficacy of LFD in improving symptoms of IBS-D, its mechanism of action is not clear. Recently, Zhou et al have shown FODMAPs induce colonic tight junction dysfunction and visceral hypersensitivity in rat models, both of which are reversible when rats were fed an LFD. They further showed that this effect of FODMAPs is mediated by microbial dysbiosis and elevated fecal lipopolysaccharide level. However, studies evaluating the effect of LFD on colonic permeability of humans are lacking. Studies have shown significant differences in intra-individual luminal and mucosal microbiome of patients with functional gastrointestinal disorders as well as an increase in Prevotella abundance in IBS patients with SIBO as compared with IBS patients without SIBO. Thus, the exact effect of FODMAP on intestinal permeability and mucosal microbiome in humans is not clear and needs further evaluation.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| low FODMAP diet | Experimental | Other: low FODMAP dietConsenting patients fulfilling the inclusion and exclusion criteria will undergo a 7-day screening period to assess baseline symptoms and then go on a 4-week low FODMAP diet |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Aged 18-65 years at the time of screening
- Meet Rome IV criteria for functional bloating
- IBS-SSS score of at 176 (0-500)
- SIBO positive
Key exclusion criteria (6 listed)
- individuals already on a LFD or other dietary restriction such as gluten free diet within the past 6 months
- individuals with peanut, soy, or seafood allergies or insulin-dependent diabetes
- known history of celiac disease, inflammatory bowel disease or microscopic colitis
- prior small bowel or colonic surgery or cholecystectomy
- pregnant patients
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 |
|---|---|---|
| low FODMAP dietlow FODMAP diet | Other | low FODMAP diet |
Primary outcome
SIBO Diagnosis
Time frame: four weeks
Number of Participants with Negative and Positive SIBO
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Jul 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 34030162Lemos MPC, Zucoloto TG, Oliveira MC, de Oliveira GLV. Dysbiosis and Gut Microbiota Modulation in Systemic Sclerosis. J Clin Rheumatol. 2022 Mar 1;28(2):e568-e573. doi: 10.1097/RHU.0000000000001748.
- Individual participant dataSharing planned: No
Related trials for SIBO
Not yet recruiting
Prevalence of Small Intestinal Bacterial Overgrowth (SIBO) in Women With Endometriosis
SIBO, Endometriosis
RecruitingObservational study
Characterization of Small Intestinal Bacterial Overgrowth and Intestinal Barrier-Related Biomarkers in Patients With Severe Periodontitis
Periodontitis (Stage 3), Periodontitis Stage IV
Enrolling by invitationPhase 2
Herbal Supplement (Biocidin REMOVE) for Bacterial Overgrowth in Irritable Bowel Syndrome
Irritable Bowel Syndrome (IBS), Small Intestinal Bacterial Overgrowth Syndrome (SIBO)
RecruitingObservational study
Small Intestinal Bacterial Overgrowth (SIBO) in Pancreatic Adenocarcinoma (PDAC)
Pancreatic Adenocarcinoma, Weight Loss
Active, not recruiting
The Safety And Efficacy Of A Probiotic Intervention On Lactulose Hydrogen Breath Test-Positive Patients And Related Gastrointestinal Symptoms
Small Intestinal Bacterial Overgrowth, SIBO
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. This study is not recruiting at the moment.
Anthony Lembo, M.D principal investigator
Beth Israel Deaconess Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing low FODMAP diet in people with SIBO, run by Beth Israel Deaconess Medical Center 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 4 inclusion and 6 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: stopped early, as of the sponsor's last update on 4 Jul 2025. 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 4 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
SIBO Diagnosis (time frame: four weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04627727, which also lists 1 linked publication.
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 4 Jul 2025.