Bariatric Surgery and Gut Microbiota Changes Over Time (NCT07381140) | Clinical Trial Compass
Not Yet RecruitingNot Applicable
Bariatric Surgery and Gut Microbiota Changes Over Time
Italy100 participantsStarted 2026-04
Plain-language summary
The goal of this observational study is to learn how bariatric surgery affects gut bacteria and gut-related metabolic products over time in adults with obesity. The study includes adults aged 18 to 65 years who are undergoing Roux-en-Y gastric bypass (RYGB) surgery, as well as adults with obesity treated with diet alone and healthy normal-weight adults.
The main questions it aims to answer are:
How does bariatric surgery change the composition and diversity of gut bacteria over time? How are these changes related to weight loss and improvement of obesity-related health conditions?
Researchers will compare people undergoing bariatric surgery with people with obesity treated with diet alone and with healthy normal-weight individuals to see if surgery leads to specific changes in gut bacteria and stool metabolites that are linked to better clinical outcomes.
Participants will:
Provide stool samples at scheduled time points over 12 months Provide blood samples and undergo routine clinical assessments Take part in follow-up visits to monitor weight, metabolic health, and gastrointestinal symptoms
Who can participate
Age range
18 Years – 65 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria (RYGB Group):
* Age between 18 and 65 years.
* Adults with a body mass index (BMI) ≥ 35 kg/m² with related comorbidities, or BMI ≥ 40 kg/m², who are candidates for Roux-en-Y gastric bypass (RYGB) surgery only.
Exclusion Criteria (RYGB Group):
* Treatment with antibiotics within the last 3 weeks, or probiotics/prebiotics within the last 4-6 weeks, or systemic corticosteroids within the 8 weeks prior to baseline (T0).
* Participation in dietary regimens or calorie restriction programs in the weeks prior to enrollment.
* Chronic inflammatory bowel diseases (e.g., Crohn's disease, ulcerative colitis), ongoing enteric infections, or active neoplasms.
* Previous organ transplant or ongoing systemic immunosuppressive therapy.
* Pregnancy or breastfeeding.
* Previous major gastrointestinal surgery.
* Chronic alcohol consumption above moderate levels or substance use disorder.
Inclusion Criteria (Obese Control Group):
* Age between 18 and 65 years.
* Adults with BMI ≥ 30 kg/m² who are candidates for structured dietary treatment.
Inclusion Criteria (Healthy Control Group):
* Age between 18 and 65 years.
* Normal weight (BMI between 18.5 and 24.9 kg/m²).
* Normal metabolic function: fasting glucose below threshold, normal ALT/AST, no diagnosis of diabetes or metabolic syndrome.
* No chronic gastrointestinal diseases or conditions that could alter the gut microbiota.
Exclusion Criteria (Obese Control and Healthy Control Group):
* Use of antibiotics within the …
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Long-Term Changes in Gut Microbiota After Bariatric Surgery
Timeframe: from enrollment up to 12 months of follow-up
Trial details
NCT IDNCT07381140
SponsorAzienda Ospedaliera Specializzata in Gastroenterologia Saverio de Bellis