IBS (Irritable Bowel Syndrome)NCT07856823
High-Resolution Measurements of Diet-Microbiome Interactions
A study testing Inulin, Atmo Gas-Sensing Capsule and CapScan Regional Fluid-Sampling Capsule in people with IBS (Irritable Bowel Syndrome), run by Stanford University at 1 site in United States.
Trial summary
The goal of this clinical trial is to characterize regional intestinal fermentation physiology and determine how the response to fermentable dietary fiber differs between healthy individuals and individuals with irritable bowel syndrome (IBS). Read more about this study
- Who is it for?
- Ages 18 to 75 yearsHealthy volunteers can take part
- Conditions the study is for
- IBS (Irritable Bowel Syndrome)
- What is being tested?
- Inulin, Atmo Gas-Sensing Capsule and CapScan Regional Fluid-Sampling Capsule
- Type of treatment
- Pill or oral medicine, Injection or infusion, Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteUnited States
- Study dates
- Oct 2026to Dec 2028
- 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 to 75 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age 18-75 years.
- Able to provide written informed consent.
- Able and willing to swallow capsules and complete all study procedures.
- For the Healthy cohort: no history of a diagnosed chronic GI disorder and no ongoing GI symptoms warranting clinical evaluation.
- For the IBS cohort: meets Rome IV diagnostic criteria for IBS, with a prior clinical hydrogen/methane breath test on record sufficient to assign a breath-test subtype.
- Willing and able to complete a virtual (Zoom) screening visit and two in-clinic study visits approximately one week apart.
Who cannot join
- Known or suspected gastrointestinal stricture or physiological/mechanical gastrointestinal obstruction.
- Gastrointestinal fistula.
- Dysphagia or other swallowing disorder affecting the ability to swallow food, pills, or capsules.
- Gastrointestinal surgery within the past 3 months.
- Prior gastrointestinal surgery that alters luminal anatomy (e.g., bowel resection or bariatric surgery).
- Diverticulitis.
Show all 19Show fewer
- Gastric bezoar.
- Radiation enteritis.
- Pacemaker or other implanted or portable electromechanical medical device.
- Pregnancy or breastfeeding.
- BMI ≥40 kg/m².
- Use of antibiotics, probiotics, or prebiotics within 4 weeks prior to enrollment.
- Use of proton-pump inhibitors (e.g., omeprazole, lansoprazole, esomeprazole [Nexium®]) within 7 days prior to the study procedure.
- Use of histamine blockers, motility-altering medications, narcotic analgesics, or anticholinergic medications within 3 days prior to the study procedure.
- Use of antiemetics/5-HT3 antagonists, macrolide antibiotics, or 5-HT4-modulating medications within 2 days prior to the study procedure.
- Use of antacids (e.g., Gaviscon®, Mylanta®, TUMS) within 1 day prior to the study procedure.
- Diabetes or use of medications affecting glucose handling.
- Known allergy or intolerance to inulin or other study meal components.
- Current participation in another interventional study.
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
Stanford University
Stanford, California, 94305
Sean P Spencer, MD, PhD, 608-469-5076, seanspen@stanford.edu
About this study
Official title: First-Principles Mapping of Regional Fermentation Physiology in the Human Intestine With Ingestible Capsules
The goal of this clinical trial is to characterize regional intestinal fermentation physiology and determine how the response to fermentable dietary fiber differs between healthy individuals and individuals with irritable bowel syndrome (IBS). The study will use ingestible capsule technologies to directly measure intestinal gases and regional microbiome composition following low-fiber and high-fiber meal challenges.
The main questions it aims to answer are:
Read more
Does the change in regional intestinal gas levels following a fermentable-fiber challenge differ between participants with IBS and healthy controls? How are regional intestinal gas dynamics associated with microbiome composition, breath gases, serum short-chain fatty acids, glucose dynamics, metabolites, and gastrointestinal symptoms?
Researchers will compare participants with IBS to healthy controls to determine whether intestinal fermentation responses to dietary fiber differ between these populations.
Participants will:
Complete two study visits approximately one week apart. At one visit, participants will receive a low-fiber control meal, and at the other visit, they will receive the same base meal containing 15 g of inulin. The order of the two meals will be assigned at random.
Swallow an Atmo gas-sensing capsule to measure intestinal H2, CO2, and O2 and a CapScan capsule to collect regional intestinal fluid for microbiome analysis.
Undergo serial blood and breath sampling and gastrointestinal symptom assessments during each 8-hour study visit.
Complete stool and urine collections, dietary assessment, and continuous glucose monitoring before and/or after the study visits.
Read the detailed description
Irritable Bowel Syndrome (IBS) affects an estimated 25-45 million people in the United States, accounts for roughly 20-40% of gastroenterology visits, and imposes a major societal burden, with annual U.S. costs estimated at approximately $1.7-$10 billion in direct medical spending and approximately $20 billion in indirect costs from lost productivity (Hulisz 2004; Leong et al. 2003; Canavan et al. 2014). Despite this burden, IBS remains poorly understood, and no validated biochemical diagnostic or curative therapy currently exists (Lacy et al. 2021; Kim et al. 2017).
In most individuals, a high-fiber diet supports a healthy microbiome and improves health outcomes without adverse symptoms (Fu et al. 2022). In patients with IBS, however, fermentable fiber is known to worsen symptoms such as bloating, flatulence, and abdominal pain; patients are often advised to restrict fermentable fiber intake (e.g., a low-FODMAP diet), and antibiotics are sometimes used therapeutically to suppress fermentation (Halmos et al. 2014; Lacy et al. 2021). These clinical observations motivate the mechanistic hypothesis underlying this protocol: that IBS symptoms may arise, at least in part, from disordered microbial fermentation and impaired intestinal gas handling.
Progress toward this goal has been limited by the absence of direct clinical tools capable of quantifying fermentation physiology in vivo and by intestinal region. Current clinical testing (e.g., hydrogen/methane breath testing) provides only an indirect, systemic proxy for fermentation and remains variably standardized (Rezaie et al. 2017; Pitcher et al. 2022).
The human intestine is more than 30 feet in length and is home to regionally distinct microbial communities that closely track local gut physiology (Martinez-Guryn et al. 2019). Recently developed non-invasive capsule-based microbiome sampling has shown that the small intestine and proximal colon harbor communities that are distinct from stool and disproportionately altered in IBS (Shalon et al. 2023; Leite et al. 2020; Chung et al. 2016).
This protocol leverages two complementary ingestible capsule technologies - a real-time gas-sensing capsule (Atmo) and a regional fluid/microbiome-sampling capsule (CapScan) - together with stool, urine, breath, and blood-based measurements, to establish regional gas production and consumption profiles in healthy individuals and patients with IBS.
The Healthy and IBS cohorts are defined by baseline clinical status and are not randomized. Within each cohort, participants undergo a randomized two-period crossover of meal order. Each participant receives both the low-fiber control meal and the 15 g inulin meal, with the order assigned at random.
- Conditions
- IBS (Irritable Bowel Syndrome)
- Being tested
- Inulin, Low-fiber control breakfast shake, Atmo Gas-Sensing Capsule, CapScan Regional Fluid-Sampling Capsule
- Keywords
- Irritable Bowel Syndrome, IBS, Inulin, Regional Microbiome, Dietary Fiber, Intestinal Microbiome, Intestinal Fermentation
- Medical subject headings
- Irritable Bowel Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
InulinDietary supplement
Participants consume a standardized breakfast shake containing 15 g of inulin at one of the two study visits, according to the randomized meal sequence. At the other visit, they consume the same base shake without added inulin as the low-fiber control. Visits occur approximately one week apart.
Low-fiber control breakfast shakeOther
Participants consume the standardized low-fiber base breakfast shake without added inulin at one of the two study visits, according to the randomized meal sequence. This condition serves as the within-participant control. Visits occur approximately one week apart.
Atmo Gas-Sensing CapsuleDevice
Also called Atmo Gas Capsule System
At each of the two study visits, participants will swallow one Atmo gas-sensing capsule with the assigned standardized breakfast shake at t=0. As it transits the gastrointestinal tract, the wireless capsule records regional luminal hydrogen (H2), carbon dioxide (CO2), oxygen-related signals, temperature, and transit-related data. Data are transmitted by radiofrequency to a wearable receiver for analysis. Capsule passage will be monitored after each visit.
CapScan Regional Fluid-Sampling CapsuleDevice
Also called CapScan, Envivo Bio Collection Device
At each of the two study visits, participants will swallow one CapScan capsule at t=4 hours. CapScan is a single-use, passive ingestible device that collects regional gastrointestinal luminal fluid as it transits the intestine. The collected samples will be used for ex vivo microbiome and multiomic analyses. The device passes in the stool and is retrieved by the participant using the provided retrieval materials for subsequent processing.
| Study group | Role | What they receive |
|---|---|---|
| Healthy controls | Experimental | The Healthy cohort consists of individuals without a diagnosed chronic gastrointestinal disorder or ongoing gastrointestinal symptoms warranting clinical evaluation. Participants complete two study visits approximately one week apart and receive both meal conditions in randomized order: low-fiber control followed by 15 g of inulin, or 15 g of inulin followed by low-fiber control. At each visit, participants consume the assigned standardized breakfast shake with the Atmo gas-sensing capsule at t=0 and ingest the CapScan regional sampling capsule at t=4 hours. Receives: Dietary Supplement: Inulin; Other: Low-fiber control breakfast shake; Device: Atmo Gas-Sensing Capsule; Device: CapScan Regional Fluid-Sampling Capsule |
| Irritable Bowel Syndrome (IBS) | Experimental | The IBS cohort consists of individuals who meet Rome IV diagnostic criteria for irritable bowel syndrome. Participants complete two study visits approximately one week apart and receive both meal conditions in randomized order: low-fiber control followed by 15 g of inulin, or 15 g of inulin followed by low-fiber control. At each visit, participants consume the assigned standardized breakfast shake with the Atmo gas-sensing capsule at t=0 and ingest the CapScan regional sampling capsule at t=4 hours. Receives: Dietary Supplement: Inulin; Other: Low-fiber control breakfast shake; Device: Atmo Gas-Sensing Capsule; Device: CapScan Regional Fluid-Sampling Capsule |
What is being measured
The primary outcome is the main question the study is designed to answer.
Successful Acquisition of a Complete Regional Multiomic Fermentation-Physiology Dataset
To successfully obtain a complete regional multiomic fermentation-physiology dataset - defined as paired Atmo gas capsule data (H2, CO2, O2), CapScan regional microbiome/fluid sampling, stool microbiome sequencing, and breath testing (H2, CH4, H2S) with serum SCFA measurements - from at least 30 of the 40 enrolled participants (15 healthy, 15 IBS), across both study visits.
Primary outcome measure: the number and proportion of enrolled participants from whom a complete multiomic dataset is successfully obtained across both study visits.
Measured: up to 12 months
Secondary outcomes (7)
Change in Regional Intestinal Gas Concentrations Following Inulin Challenge
Regional hydrogen (H2), carbon dioxide (CO2), and oxygen (O2) concentration-time profiles will be measured using the Atmo gas-sensing capsule. Changes in gas concentrations between the low-fiber control visit and the 15 g inulin visit will be compared within participants and between healthy and IBS groups, including regional differences between the small intestine and colon.
Measured: Through completion of both study visits, 2 week
Regional Intestinal Microbiome Composition Following Dietary Fiber Challenge
Microbial composition will be characterized from regional intestinal fluid samples collected using the CapScan capsule and from stool samples. Microbiome profiles will be evaluated across intestinal regions and compared between the low-fiber and inulin visits and between healthy and IBS participants.
Measured: Through completion of sample collection, up to 72 hours after each study visit
Change in Breath H2, CH4, and H2S Concentrations Following Inulin Challenge
Breath hydrogen (H2), methane (CH4), and hydrogen sulfide (H2S) concentrations will be measured every 30 minutes during each 8-hour study visit. Concentration-time profiles will be compared between the low-fiber and inulin visits and between healthy and IBS participants.
Measured: 8 hours during each study visit
Change in Serum Short-Chain Fatty Acid Concentrations Following Inulin Challenge
Serum short-chain fatty acid (SCFA) concentrations will be measured from serial blood samples collected every 30 minutes during each 8-hour study visit. SCFA concentration-time profiles will be compared between the low-fiber and inulin visits and between healthy and IBS participants.
Measured: 8 hours during each study visit
Change in Gastrointestinal Symptom Severity Following Inulin Challenge
Participant-reported gastrointestinal symptoms, including bloating/distention, abdominal pain/cramping, flatulence, nausea, and urgency, will be assessed throughout each study visit. Symptom trajectories will be compared between the low-fiber and inulin visits and between healthy and IBS participants.
Measured: 8 hours during study visit
Glucose Response Following Dietary Fiber Challenge
Continuous glucose monitor (CGM)-derived glucose profiles will be evaluated following the low-fiber and inulin meal challenges. Glucose responses will be compared within participants across study visits and between healthy and IBS groups.
Measured: Through CGM monitoring throughout 2 weeks including both study visits.
Atmo Capsule Gastrointestinal Transit Time
Quantify the gastrointestinal transit time of the Atmo capsule after participant ingestion.
Measured: From capsule ingestion through passage, confirmation up to 72 hours after clinic visit.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Oct 2026
- Study startOct 2026 (estimated)
- Primary completionOct 2028 (estimated)
- Study completionDec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for IBS (Irritable Bowel Syndrome)Studies of the same condition, open and under way.
- More trials run by Stanford UniversityThe 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Two prespecified cohorts are enrolled based on baseline clinical status: healthy controls and participants with IBS. Cohort membership is not randomized. Participants in each cohort are randomized to one of two meal sequences across two study visits approximately one week apart: (1) low-fiber control meal followed by the same base meal with 15 g of inulin, or (2) the inulin meal followed by the low-fiber control meal. Each participant receives both meal conditions and serves as their own control. Randomization determines meal order only.
- Masking
- Double blind
- Who is masked
- Participant, Care provider
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Sean Spencer, Stanford University
- Investigators
- Sean P Spencer, MD PhD, Principal investigator, Stanford UniversityMichael Fischbach, PhD, Study director, Stanford UniversityBenjamin Good, PhD, Study director, Stanford UniversityJonas Cremer, PhD, Study director, Stanford University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07856823
- Sponsor's protocol ID
- 87591
- Status last verified
- Sep 2026
- First submitted
- 28 Sep 2026
- Last updated
- 5 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 5 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- First-Principles Mapping of Regional Fermentation Physiology in the Human Intestine With Ingestible Capsules
- ClinicalTrials.gov ID
- NCT07856823
- Acronym / sponsor ID
- 87591
- Conditions
- IBS (Irritable Bowel Syndrome)
- Keywords
- Irritable Bowel Syndrome, IBS, Inulin, Regional Microbiome, Dietary Fiber, Intestinal Microbiome, Intestinal Fermentation
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Study start
- Oct 2026 (estimated)
- Primary completion
- Oct 2028 (estimated)
- Study completion
- Dec 2028 (estimated)
- First posted
- 5 Oct 2026 (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 goal of this clinical trial is to characterize regional intestinal fermentation physiology and determine how the response to fermentable dietary fiber differs between healthy individuals and individuals with irritable bowel syndrome (IBS). The study will use ingestible capsule technologies to directly measure intestinal gases and regional microbiome composition following low-fiber and high-fiber meal challenges.
The main questions it aims to answer are:
Does the change in regional intestinal gas levels following a fermentable-fiber challenge differ between participants with IBS and healthy controls? How are regional intestinal gas dynamics associated with microbiome composition, breath gases, serum short-chain fatty acids, glucose dynamics, metabolites, and gastrointestinal symptoms?
Researchers will compare participants with IBS to healthy controls to determine whether intestinal fermentation responses to dietary fiber differ between these populations.
Participants will:
Complete two study visits approximately one week apart. At one visit, participants will receive a low-fiber control meal, and at the other visit, they will receive the same base meal containing 15 g of inulin. The order of the two meals will be assigned at random.
Swallow an Atmo gas-sensing capsule to measure intestinal H2, CO2, and O2 and a CapScan capsule to collect regional intestinal fluid for microbiome analysis.
Undergo serial blood and breath sampling and gastrointestinal symptom assessments during each 8-hour study visit.
Complete stool and urine collections, dietary assessment, and continuous glucose monitoring before and/or after the study visits.
Detailed description
Irritable Bowel Syndrome (IBS) affects an estimated 25-45 million people in the United States, accounts for roughly 20-40% of gastroenterology visits, and imposes a major societal burden, with annual U.S. costs estimated at approximately $1.7-$10 billion in direct medical spending and approximately $20 billion in indirect costs from lost productivity (Hulisz 2004; Leong et al. 2003; Canavan et al. 2014). Despite this burden, IBS remains poorly understood, and no validated biochemical diagnostic or curative therapy currently exists (Lacy et al. 2021; Kim et al. 2017).
In most individuals, a high-fiber diet supports a healthy microbiome and improves health outcomes without adverse symptoms (Fu et al. 2022). In patients with IBS, however, fermentable fiber is known to worsen symptoms such as bloating, flatulence, and abdominal pain; patients are often advised to restrict fermentable fiber intake (e.g., a low-FODMAP diet), and antibiotics are sometimes used therapeutically to suppress fermentation (Halmos et al. 2014; Lacy et al. 2021). These clinical observations motivate the mechanistic hypothesis underlying this protocol: that IBS symptoms may arise, at least in part, from disordered microbial fermentation and impaired intestinal gas handling.
Progress toward this goal has been limited by the absence of direct clinical tools capable of quantifying fermentation physiology in vivo and by intestinal region. Current clinical testing (e.g., hydrogen/methane breath testing) provides only an indirect, systemic proxy for fermentation and remains variably standardized (Rezaie et al. 2017; Pitcher et al. 2022).
The human intestine is more than 30 feet in length and is home to regionally distinct microbial communities that closely track local gut physiology (Martinez-Guryn et al. 2019). Recently developed non-invasive capsule-based microbiome sampling has shown that the small intestine and proximal colon harbor communities that are distinct from stool and disproportionately altered in IBS (Shalon et al. 2023; Leite et al. 2020; Chung et al. 2016).
This protocol leverages two complementary ingestible capsule technologies - a real-time gas-sensing capsule (Atmo) and a regional fluid/microbiome-sampling capsule (CapScan) - together with stool, urine, breath, and blood-based measurements, to establish regional gas production and consumption profiles in healthy individuals and patients with IBS.
The Healthy and IBS cohorts are defined by baseline clinical status and are not randomized. Within each cohort, participants undergo a randomized two-period crossover of meal order. Each participant receives both the low-fiber control meal and the 15 g inulin meal, with the order assigned at random.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, care provider)
- Number of arms
- 2
- Model description
- Two prespecified cohorts are enrolled based on baseline clinical status: healthy controls and participants with IBS. Cohort membership is not randomized. Participants in each cohort are randomized to one of two meal sequences across two study visits approximately one week apart: (1) low-fiber control meal followed by the same base meal with 15 g of inulin, or (2) the inulin meal followed by the low-fiber control meal. Each participant receives both meal conditions and serves as their own control. Randomization determines meal order only.
| Arm | Type | Receives |
|---|---|---|
| Healthy controls | Experimental | Dietary Supplement: Inulin, Other: Low-fiber control breakfast shake, Device: Atmo Gas-Sensing Capsule, Device: CapScan Regional Fluid-Sampling CapsuleThe Healthy cohort consists of individuals without a diagnosed chronic gastrointestinal disorder or ongoing gastrointestinal symptoms warranting clinical evaluation. Participants complete two study visits approximately one week apart and receive both meal conditions in randomized order: low-fiber control followed by 15 g of inulin, or 15 g of inulin followed by low-fiber control. At each visit, participants consume the assigned standardized breakfast shake with the Atmo gas-sensing capsule at t=0 and ingest the CapScan regional sampling capsule at t=4 hours. |
| Irritable Bowel Syndrome (IBS) | Experimental | Dietary Supplement: Inulin, Other: Low-fiber control breakfast shake, Device: Atmo Gas-Sensing Capsule, Device: CapScan Regional Fluid-Sampling CapsuleThe IBS cohort consists of individuals who meet Rome IV diagnostic criteria for irritable bowel syndrome. Participants complete two study visits approximately one week apart and receive both meal conditions in randomized order: low-fiber control followed by 15 g of inulin, or 15 g of inulin followed by low-fiber control. At each visit, participants consume the assigned standardized breakfast shake with the Atmo gas-sensing capsule at t=0 and ingest the CapScan regional sampling capsule at t=4 hours. |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Age 18-75 years.
- Able to provide written informed consent.
- Able and willing to swallow capsules and complete all study procedures.
- For the Healthy cohort: no history of a diagnosed chronic GI disorder and no ongoing GI symptoms warranting clinical evaluation.
- For the IBS cohort: meets Rome IV diagnostic criteria for IBS, with a prior clinical hydrogen/methane breath test on record sufficient to assign a breath-test subtype.
Key exclusion criteria (19 listed)
- Known or suspected gastrointestinal stricture or physiological/mechanical gastrointestinal obstruction.
- Gastrointestinal fistula.
- Dysphagia or other swallowing disorder affecting the ability to swallow food, pills, or capsules.
- Gastrointestinal surgery within the past 3 months.
- Prior gastrointestinal surgery that alters luminal anatomy (e.g., bowel resection or bariatric surgery).
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 |
|---|---|---|
| InulinParticipants consume a standardized breakfast shake containing 15 g of inulin at one of the two study visits, according to the randomized meal sequence. At the other visit, they consume the same base shake without added inulin as the low-fiber control. Visits occur approximately one week apart. | Dietary supplement | Healthy controls, Irritable Bowel Syndrome (IBS) |
| Low-fiber control breakfast shakeParticipants consume the standardized low-fiber base breakfast shake without added inulin at one of the two study visits, according to the randomized meal sequence. This condition serves as the within-participant control. Visits occur approximately one week apart. | Other | Healthy controls, Irritable Bowel Syndrome (IBS) |
| Atmo Gas-Sensing CapsuleAlso: Atmo Gas Capsule SystemAt each of the two study visits, participants will swallow one Atmo gas-sensing capsule with the assigned standardized breakfast shake at t=0. As it transits the gastrointestinal tract, the wireless capsule records regional luminal hydrogen (H2), carbon dioxide (CO2), oxygen-related signals, temperature, and transit-related data. Data are transmitted by radiofrequency to a wearable receiver for analysis. Capsule passage will be monitored after each visit. | Device | Healthy controls, Irritable Bowel Syndrome (IBS) |
| CapScan Regional Fluid-Sampling CapsuleAlso: CapScan, Envivo Bio Collection DeviceAt each of the two study visits, participants will swallow one CapScan capsule at t=4 hours. CapScan is a single-use, passive ingestible device that collects regional gastrointestinal luminal fluid as it transits the intestine. The collected samples will be used for ex vivo microbiome and multiomic analyses. The device passes in the stool and is retrieved by the participant using the provided retrieval materials for subsequent processing. | Device | Healthy controls, Irritable Bowel Syndrome (IBS) |
Primary outcome
Successful Acquisition of a Complete Regional Multiomic Fermentation-Physiology Dataset
Time frame: up to 12 months
To successfully obtain a complete regional multiomic fermentation-physiology dataset - defined as paired Atmo gas capsule data (H2, CO2, O2), CapScan regional microbiome/fluid sampling, stool microbiome sequencing, and breath testing (H2, CH4, H2S) with serum SCFA measurements - from at least 30 of the 40 enrolled participants (15 healthy, 15 IBS), across both study visits. Primary outcome measure: the number and proportion of enrolled participants from whom a complete multiomic dataset is successfully obtained across both study visits.
7 secondary outcomes
Change in Regional Intestinal Gas Concentrations Following Inulin Challenge
Time frame: Through completion of both study visits, 2 week
Regional Intestinal Microbiome Composition Following Dietary Fiber Challenge
Time frame: Through completion of sample collection, up to 72 hours after each study visit
Change in Breath H2, CH4, and H2S Concentrations Following Inulin Challenge
Time frame: 8 hours during each study visit
Change in Serum Short-Chain Fatty Acid Concentrations Following Inulin Challenge
Time frame: 8 hours during each study visit
Change in Gastrointestinal Symptom Severity Following Inulin Challenge
Time frame: 8 hours during study visit
Glucose Response Following Dietary Fiber Challenge
Time frame: Through CGM monitoring throughout 2 weeks including both study visits.
Atmo Capsule Gastrointestinal Transit Time
Time frame: From capsule ingestion through passage, confirmation up to 72 hours after clinic visit.
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 5 Oct 2026.
- 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.
Sean P Spencer, MD PhD principal investigator
Stanford University
Michael Fischbach, PhD study director
Stanford University
Benjamin Good, PhD study director
Stanford University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Inulin, Atmo Gas-Sensing Capsule and CapScan Regional Fluid-Sampling Capsule in people with IBS (Irritable Bowel Syndrome), run by Stanford University 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 6 inclusion and 19 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: opening soon, as of the sponsor's last update on 5 Oct 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. 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 Roujheen Sabetan, MPH (925-963-7021, rsabetan@stanford.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Successful Acquisition of a Complete Regional Multiomic Fermentation-Physiology Dataset (time frame: up to 12 months). 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 5 Oct 2026; AzTrials last refreshed its copy on 6 Nov 2026.