Gut Microbiota

32

Review clinical trials related to Gut Microbiota. Use filters to narrow results by trial status, phase, treatment, biological sex and sponsor.

Condition / disease
Location
Status: Not yet recruiting

Gut Microbiota Structure, Functional and Metabolic Profiles, and Composite Biomarkers in ICU Adults With Refractory Enteral Feeding Intolerance

Some adults in the intensive care unit (ICU) cannot receive enough nutrition through a feeding tube because of persistent digestive problems, even after standard measures to improve feeding. This condition is called refractory enteral feeding intolerance. The community of microorganisms living in the gut, known as the gut microbiota, and the substances produced by these microorganisms and the body may be associated with feeding tolerance and recovery. This prospective observational study will enroll approximately 180 adults with refractory enteral feeding intolerance at a single hospital. It aims to describe changes in their gut microbiota and metabolic profiles over time and identify combinations of microbial markers associated with improved feeding tolerance and adequate nutritional intake. Stool samples or rectal swabs will be collected at enrollment, on days 3-5 and day 7, and, when feasible, near the end of the ICU stay. The samples will be used to examine the types of microorganisms present. Selected samples will also be analyzed for metabolic substances. Clinical information about nutrition, digestive symptoms, medications, illness severity, and treatments will be collected. Participants will be followed for up to 90 days to assess survival and unplanned hospital readmissions. The study will examine whether microbial and metabolic patterns provide additional information about feeding improvement by day 7 beyond routine clinical assessments. Where suitable public datasets are available, findings will also be evaluated in other patient groups. Participants will continue to receive usual medical care. The study does not assign treatments or change feeding decisions. Its findings may help guide future research on feeding intolerance, but participants are not expected to receive a direct medical benefit from taking part.

Participants needed: 180
Trial details
Age: 18+Biological sex: AllType: ObservationalSponsor: Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyUpdated: Oct 8, 2026Locations: 1
Eligibility criteria

Age ≥18 years. [+4]

Pregnancy or reasonable grounds for the investigator to suspect pregnancy. Activ... [+4]

Status: Recruiting

Fiber Smoothie Supplement

This study aims to assess the feasibility of a 2-week dietary whole-food smoothie intervention and compare outcomes between two groups: patients that integrated a daily whole food plant-based smoothie into their diet for two weeks prior to surgery, and a control group of revision TKA patients that made no nutritional changes to their diet prior to surgery. The main research questions are: 1. Among patients planned for elective TKA revision surgery, what is the feasibility of a 2-week dietary intervention implemented 2 weeks prior to surgery? \[Outcomes will be compliance, noted barriers and/or facilitators, satisfaction with diet\] 2. Determine if the implementation of a daily whole food plant- based smoothie dietary supplement 2 weeks prior to TKA revision surgery will reduce inflammation -measured in plasma levels of IL-6 and CRP- at POD0, POD1, POD2, POD3, and 6 Weeks Post-operative as compared to 1) baseline (prior to dietary intervention initiation) and 2) control patients who did not make changes in their diet prior to surgery. 3. Determine if the implementation of a daily whole food plant-based smoothie dietary supplement 2 weeks prior to TKA revision surgery will result in quantifiable changes in the gut microbiome composition -measured via fecal samples- as compared to control patients who did not make changes in their diet prior to surgery. 4. Determine if the implementation of a daily whole food plant- based smoothie dietary supplement 2 weeks prior to TKA revision surgery will result in improved immediate postoperative pain -measured through numeric rating scale (NRS) pain scores- and opioid use -measured in morphine milligram equivalents (MME)- as compared to control patients. 5. Compare patient satisfaction and adoption of nutritional behavioral changes in patients implementing a whole food plant-based smoothie 2 weeks prior to TKA revision surgery to patients undergoing the same surgery but did not me pre-surgery dietary changes. The researcher's primary outcome is measuring feasibility and patient compliance with smoothie consumption. Secondarily, the investigators are interested in measuring if the preoperative smoothie can alter the gut microbiome and decrease systemic inflammation, leading to lowered post-operative pain and opioid use.

Participants needed: 24
Trial details
Age: 40-80Biological sex: AllType: InterventionalSponsor: Hospital for Special Surgery, New YorkUpdated: Sep 28, 2026Locations: 1
Eligibility criteria

Scheduled for revision TKA at HSS with participating surgeons; not as a result o... [+25]

Status: Recruiting

The Impact of Overnight Active Temperature Regulation on Gut Microbiome, Inflammation, and Circadian Rhythm.

This study examines whether two continuous weeks of overnight active temperature regulation (via the Eight Sleep Pod) use affects gut microbiome composition, inflammation, and the body's daily temperature and blood pressure rhythms in postmenopausal women and age-matched men with self-reported poor sleep.

Participants needed: 100
Trial details
Age: 45+Biological sex: AllType: InterventionalSponsor: Eight Sleep Inc.Updated: Sep 30, 2026Locations: 1
Eligibility criteria

45 years of age or older [+24]

Currently taking any of the following medications/supplements or have changed us... [+153]

Status: Recruiting

GBPDC: Gut-Brain in PD Consortium Master Protocol

The purpose of this research study is to identify the role that the gut-brain axis, the group of nerves that connect the brain and gut, plays in Parkinson's disease (PD). The National Institute of Diabetes and Digestive and Kidney Diseases is sponsoring this research study. During this study, specific groups of participants, also known as "cohorts", will be identified based on the severity of their PD. There will also be a cohort enrolling participants who do not have Parkinson's and a cohort enrolling participants that are at risk for developing PD. Each of these cohorts will be compared to the others to assess the differences in the gut-brain connection. Participants in this study will: * meet with a medical provider * answer questionnaires * give samples of blood, stool, and saliva * have X-rays taken while swallowing different foods (swallowing study) * have X-rays taken to see how long it takes markers to move through their colon (colon transit study) * have a flexible sigmoidoscopy, where a doctor looks inside the lower part of the colon and takes small tissue samples (biopsies) from the mucosa (lining) * have samples taken of their skin * have an anorectal manometry and a balloon expulsion test, where a small tube and balloon are placed in the rectum to measure muscle function. Participation in the study will last up to 24 months (2 years).

Participants needed: 250
Trial details
Age: 21-80Biological sex: AllType: ObservationalSponsor: Duke UniversityUpdated: Sep 25, 2026Locations: 7
Eligibility criteria

Aged ≥21 years old and ≤80 years old [+9]

Diagnosis of secondary or atypical parkinsonism [+20]

Status: Not yet recruiting

Restrictive Versus Standard Antibiotic Treatment During CAR-T Therapy

The purpose of the CARMic study is to investigate whether a restrictive, microbiome-sparing antibiotic strategy can better preserve the gut microbiota in patients undergoing chimeric antigen receptor T-cell (CAR-T) therapy without compromising infectious safety. This is a randomized, open-label Phase II trial enrolling 150 adults with large B-cell lymphoma or multiple myeloma who are scheduled to receive standard-of-care CAR-T therapy. Participants will be randomly assigned in a 1:1 ratio to either a restrictive antibiotic strategy based on ceftazidime and/or ciprofloxacin or an unrestricted standard-of-care antibiotic strategy. The assigned strategy will apply from randomization until 28 days after CAR-T-cell infusion. Antibiotic treatment may be modified or broadened at any time when clinically indicated. The primary question is whether the restrictive antibiotic strategy results in greater gut microbial diversity 28 days after CAR-T-cell infusion compared with standard-of-care antibiotic treatment. Gut microbial diversity will be assessed in stool samples using the Shannon diversity index. The study will also compare infections, antibiotic exposure, adherence to the assigned strategy, CAR-T-related toxicities, treatment response, relapse, progression-free survival, and overall survival between the two groups. Changes in gut microbiota composition and in blood and stool metabolomic and proteomic profiles will be evaluated over time. Blood and stool samples will be collected at randomization, around the time of CAR-T-cell infusion, 28 days after infusion, and at the end-of-treatment evaluation approximately 3-6 months after infusion.

Participants needed: 150
Trial details
Phase: Phase 2Age: 18+Biological sex: AllType: InterventionalSponsor: Zealand University HospitalUpdated: Sep 25, 2026Locations: 1
Eligibility criteria

Not listed

Status: Recruiting

Organoid Models of Hepatocellular Carcinoma

A promising tool to elucidate the molecular characteristics of HCC are patient-derived organoids (PDOs), three-dimensional cultures of cells that self-organise according to tissue-specific patterns and can be used to test the susceptibility of a specific tumour to anticancer agents. In this study, PDOs for HCC will be developed that closely resemble the tumour microenvironment in vivo and mimic the crosstalk of the gut-liver axis to establish a correlation with patient prognosis and test the efficacy of available systemic therapies.

Participants needed: 150
Trial details
Age: 18+Biological sex: AllType: InterventionalSponsor: Fondazione Policlinico Universitario Agostino Gemelli IRCCSUpdated: Sep 21, 2026Locations: 1
Eligibility criteria

Capacity to express informed consent; [+2]

Age < 18 years; [+4]

Status: Not yet recruiting

Phenolic Dependent And Independent Effects Of Whole Grain Sorghum On Immunometabolism

Sorghum is a nutrient-dense ancient grain that, when eaten as a whole grain, provides health-beneficial dietary fiber, protein, and phenolics. The goal of this clinical trial is to learn about the phenolic-dependent and independent effects of whole grain sorghum in adults with excess body weight. The main questions it aims to answer are: * Are markers of immune and metabolic health affected differently by eating high- vs low-phenolic whole grain sorghum? * Does the gut microbiome respond differently to eating high- vs low-phenolic whole grain sorghum, and does this response explain the health effects? Researchers will compare foods made from (1) whole grain sumac sorghum (high phenolic profile), (2) whole grain white sorghum (low phenolic profile), and (3) white rice (control) randomly to identify the health benefits of sorghum relative to white rice. Participants will: * Consume three study foods daily during three intervention phases, with each phase lasting four weeks. The three study foods will be a cereal, crispy breadstick, and grain pouch product, which will be made from one of the study grains (sumac sorghum, white sorghum, or white rice). * Complete questionnaires asking about demographic, diet, lifestyle, quality-of-life, health, and gut health information. * Have height, weight, waist circumference, body composition, and blood pressure measured. * Wear a continuous glucose monitor 3 times, each for 10 days. * Have six blood draws, one saliva sample collection, and provide six stool samples. * Maintain a study journal during the three intervention phases.

Participants needed: 30
Trial details
Age: 19-64Biological sex: AllType: InterventionalSponsor: University of Nebraska LincolnUpdated: Sep 21, 2026Locations: 1
Eligibility criteria

Between the age of 19 and 64 years. [+14]

Has cardiac device or history of organ transplant. [+9]

Status: Recruiting

How a Single Workout Affects Gut Bugs in Women With Different Fitness Levels and Body Types

This study aims to elucidate the differences in the gut microbiome functional activity and metabolome in adult premenopausal women with distinctive fitness levels and BMIs (with obesity, w/o obesity). The specific aims are as follows: * Aim 1: To examine the effects of acute aerobic exercise at 60-70% heart rate reserve (HRRmax) for 30 minutes bout on changes in the abundance of SCFA-producing bacteria and their functional downstream metabolic activity. * Aim 2: To examine the effects of acute aerobic exercise at 60-70% HRRmax 30-minute bout on changes in GM-released SCFA concentrations in stool and plasmatic metabolome.

Participants needed: 40
Trial details
Age: 21-40Biological sex: FemaleType: InterventionalSponsor: George Washington UniversityUpdated: Sep 9, 2026Locations: 1
Eligibility criteria

Biological sex: female [+3]

Biological sex: male [+5]

Status: Recruiting

Susceptibility to Infectious Diseases in Obesity

The role of intestinal microbiota is becoming ever more important in the context of obesity, type II diabetes (T2D), and infectious disorders as represented by the emerging discipline "therapeutic microbiology". The gut microbiota is strictly interconnected with obesity and T2D playing also an important role in immune system regulation. Obesity and diabetes can lead to chronic inflammation, which results in the secretion of pro-inflammatory cytokines like IL-6, IL-1, and TNF-alpha, causing immune system alteration which predisposes patients with obesity and T2D to chronic infections. Therefore, the principal aim of the study is to investigate changes in gut microbiota composition between patients with chronic infections or not, so as to attribute to specific phyla the formation of the infections in these patients.

Participants needed: 80
Trial details
Age: 18-65Biological sex: AllType: ObservationalSponsor: Azienda Ospedaliero Universitaria Maggiore della CaritaUpdated: Sep 10, 2026Locations: 1
Eligibility criteria

age between 18-65 years [+5]

psychological conditions that reduced the ability the comprehension of the study... [+11]

Status: Recruiting

Peanuts for Cardiometabolic, Brain, and Intestinal Health

The overall objective of this 14-month randomized crossover study is to seek evidence demonstrating that daily consumption of peanuts and peanut products improve cardiometabolic, cognitive, and intestinal health in a racially diverse prediabetes population.

Participants needed: 72
Trial details
Age: 20-59Biological sex: AllType: InterventionalSponsor: Georgia State UniversityUpdated: Sep 2, 2026Locations: 1
Eligibility criteria

men and women [+4]

Allergies to peanuts and peanut products [+9]

Status: Recruiting

Wild Blueberries for Gut, Brain, and Cardiometabolic Health in Prediabetes

The goal of this clinical trial is to determine the effectiveness of using a freeze-dried wild blueberry powder on cardiometabolic health, cognitive function, and gut microbiota composition in adult women with prediabetes.

Participants needed: 30
Trial details
Age: 20-65Biological sex: FemaleType: InterventionalSponsor: Georgia State UniversityUpdated: Sep 2, 2026Locations: 1
Eligibility criteria

Women aged 20-65 years old [+2]

Allergies to berries [+8]

Status: Not yet recruiting

Analysis of the Role of the Microbiota in Diverticular Disease

A single-center, prospective observational cohort study conducted at the University Hospital of Navarra. The primary objective is to expand knowledge of diverticular disease and its pathological variants, as well as the influence of the microbiota in our environment, both clinically and molecularly; to describe the clinical and pathological characteristics of patients with diverticulosis and acute diverticulitis; to analyze any differences in the microbiota; and to identify the risk factors and groups associated with diverticular disease in order to establish the best strategies for prevention and treatment.

Participants needed: 285
Trial details
Age: 18+Biological sex: AllType: ObservationalSponsor: Hospital of NavarraUpdated: Sep 2, 2026Locations: 1Duration: 24 Months
Eligibility criteria

Age 18 or older. [+2]

An episode of acute diverticulitis located in the right colon or transverse colo... [+5]

Status: Recruiting

Developing Precision Microbiota-Based Cocktail Modification Therapy to Delay the Progression of Parkinson's Disease (PD) - Use Preclinical Human Trials to Confirm the Impact of the Optimal "Probiotic Y7, Tryptophan and Branched-chain Amino Acid" Cocktail Formula on Early Stage PD Patients

Preclinical human trials will be utilized to validate the research direction, followed by clinical trials to assess the impact of a cocktail formula product containing the optimal probiotic Y7 combined metabolites on motor, cognitive, and non-motor functions in early Parkinson's disease patients. The study aims to recruit 120 patients (stage 1-3) and employ a two-arm, randomized controlled trial (RCT) design, dividing subjects into intervention and control groups for a 12 weeks trial period. Commercial development will be contingent upon the clinical trial outcomes, evaluating whether the product offers clinical benefits such as delaying Parkinson's disease progression in motor, cognitive, and non-motor functions. Additionally, a personalized and precise prognosis prediction model for Parkinson's disease will be established. This model will gather comprehensive clinical data, including motor function assessments (functional tests, UPDRS), biochemical markers, questionnaire responses, and genotype data (TPM array), as well as metabolite and microbial data. Through integrated analysis of this biological information using machine learning techniques, a personalized and accurate prognosis prediction model for Parkinson's disease will be developed. This model will predict the disease status of PD patients 12 weeks later, accounting for factors such as cocktail therapy. The results will empower PD patients to understand their individual disease progression and treatment prognosis, enabling them to prepare accordingly. Moreover, this model will aid researchers in identifying patient profiles more likely to benefit from treatment, thereby enhancing the evaluation of the efficacy and applicability of cocktail therapy.

Participants needed: 120
Trial details
Age: 30-85Biological sex: AllType: InterventionalSponsor: Taipei Medical UniversityUpdated: Jun 2, 2026Locations: 1
Eligibility criteria

Age between 30-85 years old. [+5]

Unable to complete interviews or has mobility issues. [+4]

Status: Recruiting

Pesticides and Infertility: Oxidative Stress Via Circulating Cell-free DNA and Gut/Genital Microbiome Signatures in Women With Endometriosis

This project PestiEndoMicro aims to provide an innovative approach, studying endometriosis under the genital and gut microbiota scope. To realize this project, the investigators are planning to dose cfDNA to assess the oxidative stress caused by endometriosis and study its epigenetics. At the same time, the investigators will take a pragmatic approach by assessing pesticide exposure in these patients and estimate the correlation between gut or genital dysbiosis and chemical agent exposure. Also, the investigators will take the initiative to use classic culture, qPCR techniques, and NGS to establish signatures in vaginal, endometrial and gut microbiota in patients with endometriosis. With these approaches, the goal is to gain more knowledge about endometriosis and optimize early diagnosis by establishing a signature in the genital and gut microbiota, but also by dosing the cfDNA. By doing so the investigators could open new opportunities to develop new therapeutic strategies for endometriosis.

Participants needed: 160
Trial details
Age: 18-43Biological sex: FemaleType: InterventionalSponsor: Centre Hospitalier Universitaire, AmiensUpdated: May 15, 2026Locations: 1
Eligibility criteria

All women aged 18 to 43, with confirmed endometriosis and endometriosis grade 3... [+4]

All women aged 44 and over. [+7]

Status: Recruiting

Effect of Dairy Protein Yogourt vs Plant-based Yogourt on Body Weight, Body Composition, Bone Health and Gut Microbiota

The consumption of an adequate quantity of protein in the diet is essential to maintain a healthy body composition and functioning. It is also well established that all proteins are not equal regarding their ability to promote health benefits. Recently, we have innovated in that matter by showing that under the context of high intake of dietary fat, the dairy protein casein was more effective than a mix of proteins representative of a western diet to prevent body weight gain and insulin resistance. This was explained in part by modifications of the gut microbiota. This finding represents the main conceptual basis of the present research program that is aimed to determine the impact of dairy protein from yogurt compared to a plant-based equivalent on body composition indicators including muscle mass and bone mineral density, in relation to the profile of the gut microbiota, the production of newly discovered protein-derived metabolites, and markers of metabolic health. This program will include a human and an animal component requiring the testing of these variables before and after a standardized intervention. The human component will be a clinical study consisting of a 12-week diet-based weight loss intervention in postmenopausal overweight women being randomly assigned to one of the three following groups: yogurt, plant-based yogurt, or kept on diet without supplements. The animal experimentation will permit to causally determine the implication of the gut microbiota in the protein effects following transfer of the human bacteria to germ free mice and validate the benefits seen in humans. It is anticipated that these two complementary investigative approaches will allow a thorough documentation of the impact of fermented dairy protein on body composition and functioning, a better understanding of the underlying mechanisms, and the identification of new biomarkers to better appreciate related health benefits.

Participants needed: 75
Trial details
Age: 40+Biological sex: FemaleType: InterventionalSponsor: Laval UniversityUpdated: May 11, 2026Locations: 1
Eligibility criteria

Postmenopausal women (absence of menstruation for at least 1 year and FSH > 40 I... [+2]

Body weight change greater than 5 kg in the 3 months preceding the study [+12]

Status: Recruiting

Sustainable and Inclusive Use of Alternative Proteins in Mediterranean Supply Chains (CIPROMED)

This study investigates the effects of foods enriched with alternative protein sources, including edible insects, microalgae, hemp, and legumes, on appetite regulation, satiety, food preferences, and metabolic health in healthy adults and individuals with overweight. The study is part of the CIPROMED project, which aims to support sustainable and circular food systems in the Mediterranean area. The study consists of two phases. In the acute phase, participants will consume different protein-enriched bread products in a controlled setting following a randomized crossover design. Each participant will be exposed to multiple test conditions, allowing within-subject comparisons of postprandial responses. Outcomes assessed during this phase include satiety, hunger, food preference, craving, and short-term energy intake, measured using validated scales and dietary assessment tools. In the chronic phase, participants will follow structured dietary interventions over a longer period within a Mediterranean dietary framework. Participants will be assigned to different dietary patterns including alternative protein-based foods and control products. This phase aims to evaluate the effects of repeated consumption of alternative protein sources on metabolic parameters, gastrointestinal tolerance, nutritional status, and behavioral responses. The study aims to assess the acceptability and physiological effects of alternative protein sources and to compare their impact with that of traditional protein sources commonly used in Mediterranean diets.

Participants needed: 40
Trial details
Age: 18-65Biological sex: AllType: InterventionalSponsor: University of BolognaUpdated: May 4, 2026Locations: 1
Eligibility criteria

Providing signed informed consent, [+2]

Positive and documented history of allergy to legumes, insects, microalgae, shel... [+2]

Status: Recruiting

MiCrobiota-gut-brain Axis in Resistant Epilepsy

Epilepsy is one of the most common neurological chronic conditions with a serious burden on patients, their caregivers, and society. Drug-resistant epilepsy (DRE) heightens this burden. New approaches are thus a priority. Studies in animal models and humans have shown the link between gut microbiota (GM) and the central nervous system in health, neurological conditions, and neurodevelopmental disorders. DRE has been linked to GM dysbiosis. Preliminary findings in children with DRE showed GM modifications when responding to a ketogenic diet. The mediator role of GM has not yet been studied in DRE patients undergoing surgery/vagal nerve stimulation. CARE's central hypothesis is that the GM and its metabolic profile could contribute to clinical outcomes following these different therapeutic procedures. Identifying microbial biomarkers will enable us to deepen the knowledge of the role of gut-brain axis in epilepsy and to tailor the intervention to each patient based on GM modulation.

Participants needed: 120
Trial details
Age: 3-50Biological sex: AllType: InterventionalSponsor: Niguarda HospitalUpdated: Apr 9, 2026Locations: 1
Eligibility criteria

3-50 years old; [+3]

diagnosis of organic gastrointestinal disorders (e.g. chronic inflammatory bowel... [+2]

Status: Not yet recruiting

Clinical Trial of Lactiplantibacillus Plantarum Dad-13 on Gut Microbiota Profile and Performance in Adolescent Athletes

The aim of this research is to analyze the effect of a Lactiplantibacillus plantarum Dad-13 supplementation on the gut microbiota profile and performance of adolescent athletes.

Participants needed: 30
Trial details
Age: 12-18Biological sex: AllType: InterventionalSponsor: Gadjah Mada UniversityUpdated: Mar 23, 2026Locations: 1
Eligibility criteria

Residing in the BPPLOP dormitory of Central Java Province; [+3]

Injury, any health contraindication or failure to perform exercise procedures; [+4]

Status: Recruiting

Lifestyle Interventions to Prevent Cognitive Deficits in Subjects With Depressive Symptoms: From Mechanisms to Clinical Practice

The goal of this clinical study is to investigate if lifestyle changes can help prevent cognitive decline and reduce depressive symptoms in people between the ages of 50 and 80 with depressive symptoms or a diagnosis of major depression, but without signs of cognitive decline. The main questions it aims to answer are: * Does regular physical activity improve mood and memory in people who are depressed or have depressive symptoms? * Does cognitive training help prevent mental difficulties in people at risk of cognitive decline? * Do changes in diet and lifestyle alter the composition of the gut microbiota and immuno-related infiammatory factors? Researchers will compare three different treatment groups to see which intervention is most effective in improving mental and cognitive health. The participants: * Will take part to online sessions on healthy eating based on the Mediterranean diet * Some will do regular exercise, supervised by a personal trainer * Others will do weekly cognitive training in small groups at the hospital * They will provide blood and fecal samples and complete cognitive tests and clinical questionnaires at the beginning, at the end of the treatment (12 weeks), and after 3 months.

Participants needed: 120
Trial details
Age: 50-80Biological sex: AllType: InterventionalSponsor: IRCCS Centro San Giovanni di Dio FatebenefratelliUpdated: Feb 11, 2026Locations: 1
Eligibility criteria

Aged between 50 and 80 years; [+2]

Active gastrointestinal disorders; [+4]

Status: Recruiting

The Efficacy of PD-1 Monoclonal Antibody Combined With Chemotherapy in Metastatic Gastric Cancer Based on Gut Microbiota

This study is designed as a single-center, open-label, phase II exploratory trial. Patients with advanced or locally advanced gastric cancer who have not received chemotherapy or immunotherapy before are eligible for inclusion. They will receive a first-line two-drug combination chemotherapy regimen (FOLFOX, XELOX, or SOX, determined by the attending physician) in combination with a PD-1 monoclonal antibody (nivolumab, sintilimab, tislelizumab, or pembrolizumab, determined by the attending physician). Fruquintinib can be added on this basis (only for patients enrolled in the HMPL-013-SH-GC103 study). The aim is to evaluate whether the gut microbiota has a predictive role in the efficacy of immunotherapy combined with chemotherapy for metastatic gastric cancer. A total of 100 patients will be enrolled in the study. Gut microbiota will be measured at the following three time points: 1. Within 3 days before the first chemotherapy (designated as time 0) 2. Within 3 days before the third chemotherapy (designated as time 1) 3. After the sixth chemotherapy cycle, or within 1 week after disease progression if it occurs within the sixth cycle (designated as time 2)

Participants needed: 300
Trial details
Age: 18+Biological sex: AllType: ObservationalSponsor: Fudan UniversityUpdated: Feb 10, 2026Locations: 1Duration: 2 Years
Eligibility criteria

Age ≥ 18 years, gender not restricted; [+6]

Pregnant or lactating women, and women of childbearing age who have not taken ad... [+6]

Status: Not yet recruiting

Bariatric Surgery and Gut Microbiota Changes Over Time

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

Participants needed: 100
Trial details
Age: 18-65Biological sex: AllType: ObservationalSponsor: Azienda Ospedaliera Specializzata in Gastroenterologia Saverio de BellisUpdated: Feb 5, 2026Locations: 1
Eligibility criteria

Age between 18 and 65 years. [+1]

Treatment with antibiotics within the last 3 weeks, or probiotics/prebiotics wit... [+20]

Status: Not yet recruiting

High-Dairy Food Patterns and Gut-Brain Axis

Disturbances in brain insulin sensitivity are associated not only with obesity and type 2 diabetes, but also with brain aging and cognitive decline. Longitudinal studies suggest that dietary patterns, particularly those high in dairy intake, may impact brain function via the gut-brain axis. Indeed, dairy foods are known to modulate gut microbiota and may, through this pathway, not only improve brain insulin sensitivity and cognitive performance, but also mental health and appetite regulation. However, underlying mechanisms remain largely unexplored. The primary objective of this study is to evaluate, in older adults with overweight or obesity, the effects of a high-dairy food pattern (4-5 daily servings of (butter)milk, cheese, yogurt, or cottage cheese) compared to a low-dairy food pattern (≤1 serving daily) on (regional) brain vascular function and insulin sensitivity. These outcomes will be quantified using the non-invasive MRI perfusion technique Arterial Spin Labeling (ASL), which assesses cerebral blood flow (CBF) in response to intranasal insulin, a validated physiological marker of brain insulin sensitivity. Secondary objectives include changes in cognitive performance (via the CANTAB neuropsychological test battery), gut microbiota composition (via shotgun metagenomic analysis of fecal samples), and appetite-related brain reward activity (via BOLD-fMRI with food cues). Exploratory analyses include conventional cardiometabolic risk markers (blood pressure, lipid and glucose metabolism), and perceivable (consumer) benefits.

Participants needed: 40
Trial details
Age: 40-75Biological sex: AllType: InterventionalSponsor: Maastricht University Medical CenterUpdated: Jan 21, 2026Locations: 1
Eligibility criteria

Men and postmenopausal women (≥ 2 years since last menstruation); [+8]

Left-handedness; [+14]

Status: Recruiting

SMASH: Study to Evaluate the Clinical Efficacy of an Extensively Hydrolysed Infant Formula With Synbiotics and a Human Milk Oligosaccharide (HMO) in Infants With Cow's Milk Protein Allergy (CMPA)

Cow's milk protein allergy (CMPA) is one of the most common food allergies in infants, with an estimated prevalence between 2% and 5%. The number of diagnosed cases has increased in recent years, with clinical manifestations involving the gastrointestinal tract, respiratory system, skin, or systemic reactions. Dietary elimination of cow's milk protein remains the mainstay of treatment, using extensively hydrolyzed formulas (EHF) or amino acid-based formulas (AAF), depending on the severity of the allergy. This study aims to evaluate the clinical effect, as reported by physicians, of an extensively hydrolyzed whey-based formula (Almirón Pepti Syneo®) containing a symbiotic mixture (scGOS/lcFOS 9:1 and Bifidobacterium breve M-16V), the human milk oligosaccharide 2'-fucosyllactose (2'-FL), and a reduced amount of purified lactose, in infants with suspected or confirmed CMPA in a real-world clinical practice setting. This is a prospective, longitudinal, open-label, single-arm, multicenter study including approximately 41 infants under 10 months of age at several primary care centers and one hospital in Valencia, Spain. Each participant will be followed for four weeks. A subgroup of participants will also provide stool samples to explore the effect of the study formula on gut microbiota composition.

Participants needed: 41
Trial details
Age: Up to 10Biological sex: AllType: ObservationalSponsor: Outcomes'10Updated: Jan 15, 2026Locations: 13Duration: 4 Weeks
Eligibility criteria

Infants under 10 months of age at study start (Visit 1). [+4]

Infants with functional gastrointestinal symptoms in whom atopy or food allergy... [+6]

Status: Recruiting

Impact of Transcatheter Aortic Valve Implantation (TAVI) on the Gut Microbiota in Patients With Aortic Valve Stenosis

This study investigates the impact of transcatheter aortic valve implantation (TAVI) on the composition and function of the gut microbiota in patients with severe aortic valve stenosis. The improvement in haemodynamics following TAVI may positively influence gut microbial balance by increasing splanchnic perfusion and reducing intestinal congestion. A total of 40 patients undergoing TAVI at the "Hippokration" General Hospital of Athens will be enrolled, with the aim of analysing stool and blood samples before and after the procedure. The primary endpoint is the change in gut microbiota composition two months post-TAVI, assessed via 16S rRNA sequencing. Secondary endpoints include changes in serum TMAO levels and their association with the severity of aortic stenosis and post-procedural valve haemodynamics. Data will be collected at two timepoints (1 month up to 1 day pre-TAVI and 3 to 4 months post-TAVI), along with dietary questionnaires to account for potential confounding factors. This observational study aims to highlight the potential relationship between cardiac function and the gut microbiome, offering new perspectives for targeted therapeutic strategies in cardiovascular disease.

Participants needed: 40
Trial details
Biological sex: AllType: ObservationalSponsor: Hippocration General HospitalUpdated: Nov 18, 2025Locations: 1
Eligibility criteria

Aortic stenosis suitable for TAVI

Use of antibiotics, systemic corticosteroids, antivirals, probiotics, bile acid... [+7]

Status: Recruiting

Gut Mini-Pill Study

The purpose of this proof-of-concept study in humans is to determine if a noninvasive, ingestible device, called a "mini-pill", can collect gastrointestinal (GI) luminal content samples from 2 different locations along the GI tract after consumption of diets differing in protein source (meat and plant-based meat alternatives). The mini-pills will be recovered in the stool. We will analyze the microbial profile of the mini-pill contents and in stool, and also measure blood biomarkers related to cardiometabolic risk, to better understand the relationship between diet, microbiota and health.

Participants needed: 30
Trial details
Age: 50-75Biological sex: AllType: InterventionalSponsor: Tufts UniversityUpdated: Oct 30, 2025Locations: 1
Eligibility criteria

Men and postmenopausal women [+9]

Individuals self-reporting adhering to any type of vegetarian diet [+20]