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47 clinical studies listed.

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Microbiome

Tundra lists 47 Microbiome clinical trials. Each listing includes eligibility criteria, study locations, and direct links to research sites in the Tundra directory.

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ACTIVE NOT RECRUITING

NCT07866469

Norovirus Prevalence and Fecal Microbiome Characterization Through Metagenomic and Metatranscriptomic Analyses

The goal of this clinical trial is to characterize the fecal microbiome composition (including bacteria, archaea, viruses, fungi, and parasites) in fecal samples collected from travelers (including occupational travelers, leisure travelers, Visiting Friends and relatives (VFR), and migrants) attending the center, This is a exploratory, experimental study using samples archived in the local biobank which involves analyses such as metagenomic and metatranscriptomic analyses of fecal samples.

Gender: All

Updated: 2026-10-08

1 state

Microbiome
Metagenomic Next Generation Sequencing
Norovirus Infection
WITHDRAWN

NCT06702280

Assessing the Safety of an IGY Supplement on the Gut Microbiome

This study is to evaluate whether Muno-IgY is effective in enhancing immune health among adults over a six week period.

Gender: All

Ages: 18 Years - 65 Years

Updated: 2026-09-30

1 state

Healthy
Microbiome
RECRUITING

NCT07623902

Evaluation of Gixam's Efficacy Predicting the Presence of Advanced and Non-advanced Colorectal Neoplasia in a FIT Negative Population

The goal of this clinical trial is to learn if the Gixam device effectively identifies persons with pre-cancer or cancer in the colon and rectum in adults aged 45-84 that are of average risk to develop colorectal cancer and have received a negative result on a Fecal Immunochemical Test (FIT). The main questions it aims to answer are: 1. Is the Gixam Device effective in identifying persons with pre-cancer or cancer in the colon and rectum that have received a negative FIT result? 2. Is the use of the Gixam device safe? Gixam test result will be compared to the findings of a standard of care screening colonoscopy. Study participants will: 1. Undergo the Gixam test 2. Take a FIT at home and ship to a laboratory. 3. Undergo a standard of care screening colonoscopy.

Gender: All

Ages: 45 Years - 84 Years

Updated: 2026-09-21

7 states

CRC Screening
Microbiome
COMPLETED

NCT07439718

The Effects of an Oral Nutritional Intervention on the Small Intestine Microbiome

This is a single-center, single-arm study, aiming at enrolling 25 healthy adult participants to evaluate chronic effects of oil. Specifically, we aim to assess the impact on gut microbiome after a one-month intervention with oil.

Gender: All

Ages: 18 Years - 60 Years

Updated: 2026-09-17

Microbiome Composition
Microbiome
COMPLETED

NCT07805837

Comparative Immunologic Mechanisms and Microbiome Interactions Following Different Influenza Vaccine Formulations in Older Adults

This prospective, randomized, open-label clinical study aims to evaluate the immunogenicity and underlying immune mechanisms of different influenza vaccine formulations in adults aged ≥65 years. Additionally, the study investigates the role of the gut microbiome in modulating vaccine-induced immune responses and durability.

Gender: All

Ages: 65 Years - Any

Updated: 2026-09-04

1 state

Influenza
Influenza Vaccines
Microbiome
+1
RECRUITING

NCT07791849

GMPA Versus PPI for Gastric Protection and aGVHD Risk

The goal of this clinical trial is to observe whether different gastric protection strategies affect the incidence of acute graft-versus-host disease (aGVHD) in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Proton pump inhibitors (PPIs) are routinely used for gastric protection during transplantation, but their prolonged use may suppress gastric acid, alter gut microbiota, and potentially increase the risk of aGVHD. Teprenone, a gastric mucosal protective agent (GMPA), enhances mucosal defense mechanisms including promoting mucus secretion, increasing gastric mucosal blood flow, and facilitating epithelial cell repair, without affecting gastric acid secretion, and may therefore preserve microbial diversity and modify aGVHD risk. This study compares two strategies: continuous PPI use versus switching from PPIs to teprenone after transplantation. The main questions this study aims to answer are: * Does switching from PPIs to teprenone after transplantation reduce the cumulative incidence of aGVHD within +100 days post-transplantation compared with continuous PPI use? * What adverse events do participants experience with teprenone versus continuous PPI therapy? * Does teprenone therapy provide better preservation of gut microbial diversity and lower rates of gastrointestinal and infectious complications compared with continuous PPI use? In this prospective, randomized, parallel-controlled, single-center trial, approximately 198 patients undergoing allo-HSCT will be enrolled and assigned in a 1:1 ratio using a central randomization system. The experimental group (teprenone group) will receive standard-dose PPIs (esomeprazole, 40 mg/d, intravenous/oral) during conditioning and switch to teprenone (50 mg tid, orally) after transplantation through day +100. The control group (PPI group) will receive continuous standard-dose PPIs from conditioning through day +100. Probiotic use is prohibited from conditioning through day +100 in both groups. All other anti-infective, GVHD prophylaxis, and supportive care regimens are identical between the two groups. The primary endpoint of this study is the cumulative incidence of aGVHD within +100 days post-transplantation. Secondary endpoints include grade II-IV and grade III-IV aGVHD, lower gastrointestinal aGVHD, steroid-refractory aGVHD, gut and salivary microbiome dynamics (α-diversity, β-diversity, and specific taxa at pre-conditioning, day 0, day +14, and day +28), plasma biomarkers related to intestinal barrier integrity, systemic inflammation, and immune regulation , infectious and gastrointestinal complications (febrile neutropenia, diarrhea, C. difficile infection, bacteremia, EBV/CMV reactivation, upper GI bleeding, reflux), and 1-year survival outcomes (non-relapse mortality, overall survival, GVHD-free/relapse-free survival). During the study, participants will: * Receive the assigned gastric protection regimen (teprenone or PPI) according to randomization * Undergo regular assessments for safety and efficacy monitoring, including aGVHD surveillance and infection screening * Provide fecal and saliva samples at pre-conditioning, day 0, day +14, and day +28 post-transplantation for microbiome analysis * Provide peripheral blood samples at pre-conditioning, day 0, day +14, and day +28 post-transplantation for exploratory analysis * Be followed for up to 1 year post-transplantation

Gender: All

Ages: 12 Years - 70 Years

Updated: 2026-08-28

Hematopoietic Stem Cell Transplantation (HSCT)
aGVHD
Infection
+2
NOT YET RECRUITING

NCT07788924

Assessing Changes in the Gut Microbiome of Non-Gastrointestinal Disordered Subjects Before and After Oral Prebiotic Supplementation Using the SIMBA Capsule

This is a randomized, double-blind, placebo-controlled, parallel-group clinical study. The primary objective is to assess the changes in the small intestinal (SI) metagenomic profile of healthy participants without any known gastrointestinal disorders from baseline to endpoint in response to the prebiotic intervention (FiberSmart). The study population are adults (n=30) who will ingest either the FiberSmart or a matched Placebo daily for 21 days. Both products will be referred to as the Investigational Product (IP) in the study procedures section. While prebiotics are widely used for gut health, their specific impact on the small intestinal ecosystem remains largely uncharacterized compared to the large intestine. Understanding their impact on the upper GI tract can lead to new insights into their mechanisms of action. Given the critical role of the small intestine in metabolism and immunity, the study utilizes the SIMBA capsule to measure novel changes in the small intestine along with traditional measurements from stool samples.

Gender: All

Ages: 19 Years - 40 Years

Updated: 2026-08-27

Prebiotics
Metagenomic Next Generation Sequencing
Microbiome
+1
ACTIVE NOT RECRUITING

NCT07781488

A Clinical Trial to Evaluate the Effects of a Fibre Supplement on Microbiome and Gut Health

This study will evaluate the effects of the Artah Essential Fibre+ supplement on the microbiome and gut health over an 8-week period. The study is a single-arm, unblinded virtual trial enrolling 50 participants who will consume the test product daily and complete questionnaires at Baseline, Week 2, Week 4, Week 6, and Week 8. A subgroup of 30 participants will provide stool samples for microbiome testing at Baseline and Week 8. All participants will provide body composition measurements using a smart scale at Baseline, Week 4, and Week 8. Secondary outcomes include participants' self-reported perceptions of the product's effects on gut health, metabolism, food cravings, appetite, and general well-being.

Gender: All

Ages: 21 Years - 65 Years

Updated: 2026-08-24

1 state

Gut Health
Microbiome
Bloating
+6
COMPLETED

NCT07364383

Probiotics for Women

Investigation into the effect of probiotic supplementation on the wellbeing of women with a history of vaginal discomfort and/or irritation, along with any microbiome changes.

Gender: FEMALE

Ages: 18 Years - 40 Years

Updated: 2026-08-20

Probiotic
Microbiome
Wellbeing
NOT YET RECRUITING

NCT07705217

The Role of Gut and Skin Microbiota in Alopecia Areata

The goal of this clinical trial is to learn if fecal microbiota transplantation (FMT) works to treat alopecia areata in adults. It will also learn about the safety of FMT. The main questions it aims to answer are: * Can FMT cause hair regrowth? * Can FMT modulate immune response? Researchers will compare FMT to a placebo (a look-alike substance that contains no drug) to see if FMT works to treat alopecia areata. Participants will: * Take FMT or a placebo for three consecutive days * Follow-up evaluations will be performed at weeks 12, 24, and 48, with repeat clinical scoring, photodocumentation, microbiome analyses, laboratory testing, and quality-of-life assessment.

Gender: All

Ages: 18 Years - 65 Years

Updated: 2026-07-15

Alopecia Areata
Fecal Microbiota Transplantation (FMT)
T Cell Subsets
+1
ACTIVE NOT RECRUITING

NCT04552834

Alterations of the Microbiome During Critical Illness With Short and Long Term Clinical Outcomes

This study is designed to study the variations in the microbiome among critically ill patients and the effect of admission to the medical intensive care unit (MICU) at the University of Chicago. Additionally, investigators will examine the downstream clinical effects of dysbiosis in ICU patients and how patients maybe effected long term.

Gender: All

Ages: 18 Years - Any

Updated: 2026-07-13

1 state

Critical Illness
Microbiome
NOT YET RECRUITING

NCT07525739

Assessing Changes in the Gut Microbiome of Non-Gastrointestinal Disordered Subjects Before and After Oral Prebiotic Supplementation Using the SIMBA Capsule

This is a randomized, double-blind, placebo-controlled, parallel-group clinical study. The primary objective is to assess the changes in the small intestinal (SI) metagenomic profile of healthy participants without any known gastrointestinal disorders from baseline to endpoint in response to the prebiotic intervention (FiberSmart). The study population are adults (n=30) who will ingest either the FiberSmart or a matched Placebo daily for 21 days. Both products will be referred to as the Investigational Product (IP) in the study procedures section. While prebiotics are widely used for gut health, their specific impact on the small intestinal ecosystem remains largely uncharacterized compared to the large intestine. Understanding their impact on the upper GI tract can lead to new insights into their mechanisms of action. Given the critical role of the small intestine in metabolism and immunity, the study utilizes the SIMBA capsule to measure novel changes in the small intestine along with traditional measurements from stool samples.

Gender: MALE

Ages: 19 Years - 40 Years

Updated: 2026-07-10

1 state

Prebiotic
Metagenomic Next Generation Sequencing
Microbiome
+1
ENROLLING BY INVITATION

NCT06657001

Enabling Microbiomics- Driven Personalized Nutrition

The goal of this observational research study is to determine how diet contributes to various gastrointestinal related conditions. The main question investigators aim to answer is: Are host genetics, diet, and microbiome all important determinants of GI disorders, and how their relative contribution varies among individuals and populations.

Gender: All

Ages: 18 Years - Any

Updated: 2026-06-12

1 state

Inflammatory Bowel Disease (IBD)
Irritable Bowel Syndrome (IBS)
Celiac Disease
+7
COMPLETED

NCT07570043

A Study to Evaluate the Efficacy of a Postbiotic Supplement on Menopausal Symptoms in Premenopausal Women

The goal of this consumer health study is to evaluate the effect of resW™ Perimenopause Postbiotic on menopausal symptom severity, menopause-related quality of life, and selected microbiome-related outcomes in generally healthy perimenopausal women aged 35 to 55 years. Participants will be randomized to receive either the active supplement or placebo daily for 4 weeks. Participants will complete electronic questionnaires at baseline and during the study. A predefined subset of participants will also complete stool and vaginal sample collection at baseline and Week 4.

Gender: FEMALE

Ages: 35 Years - 55 Years

Updated: 2026-06-01

1 state

Perimenopause
Menopausal Symptoms
Menopause-Related Quality of Life
+1
NOT YET RECRUITING

NCT07195474

Smoothie Program for Achieving and Resilient Kids

The proposed study will examine whether eating yogurt every day can improve brain and gut health in children. Prior research suggests that yogurt may support cognitive functions like self-control, but more studies are needed to confirm this. The study will follow 60 children from Central Pennsylvania, ages 8 to 10, who will be randomly assigned to drink either fruit juice (control group) or yogurt smoothies once or twice a day for four weeks. Researchers will compare how different amounts of yogurt affect children's thinking skills (like memory and focus), brain activity, and gut bacteria. These changes will be measured through brain scans, computer-based thinking tasks, surveys, and stool samples. The study will also collect information about children's overall diet. The goal is to find out if yogurt can support healthy brain and gut development and to determine the right amount to include in a child's daily diet. Results will help guide future research on how nutrition supports children's health.

Gender: All

Ages: 7 Years - 9 Years

Updated: 2026-05-20

1 state

Executive Functions (EF)
Microbiome
Dietary Quality
RECRUITING

NCT07600008

Development of a Preparation for Supportive Supplementation of Probiotics in Patients With Reflux

A two-arm, double-blind, randomized, placebo-controlled study investigating the efficacy of a probiotic preparation developed as supportive supplementation of probiotics in patients with reflux. The objective of this trial is to evaluate the effect of the probiotic dietary supplement on the diversity and composition of the gut microbiome in patients diagnosed with GERD who are on PPI therapy. The study will also monitor changes in the oral microbiome and the impact of probiotic supplementation on patient quality of life and GERD symptoms. Patients will take the probiotic preparation, 2 tablets twice daily (morning before meals and evening after meals). The experimental phase will last 6 weeks. Patients in the control arm will receive placebo. Supplementation will be discontinued if adverse effects occur. Oral and rectal swabs will be taken before and after administration of the preparation. Patients will monitor their symptoms using a questionnaire.

Gender: All

Ages: 40 Years - 55 Years

Updated: 2026-05-20

Reflux Disease
Microbiome
Probiotics Supplement
NOT YET RECRUITING

NCT07594860

Effect of a Probiotic or Postbiotic on Gut Microbiome During Antibiotic Treatment

This study assesses the effects of a probiotic or postbiotic on gut microbiome during antibiotic treatment.

Gender: All

Ages: 18 Years - 65 Years

Updated: 2026-05-19

Microbiome
RECRUITING

NCT06741293

Improving Colorectal Cancer Early Screening in Portugal: Identification of Gut Microbiome Biomarkers in Stool (GUTBIOME-PT)

Colorectal cancer (CRC) is a major public health problem, responsible for 2 million new cases and almost 1 million deaths annually worldwide. In Portugal, as of 2022, CRC is the most common cancer, with 10,575 new cases reported, and the second leading cause of cancer-related mortality, accounting for 4,809 deaths (approximately 14% of all cancer-related deaths). In recent years, there has been an alarming increase in the incidence and mortality of CRC in people \<50 years of age. Early detection is crucial, as survival rates decline sharply from 90% when detected early to just 10% in advanced stages. Non-invasive diagnostic tests, such as the Faecal Immunochemical Test (FIT), have a low sensitivity for early-stage lesions and a high rate of false positives. Therefore, there is an urgent need to improve non-invasive diagnostic methods for the early detection of CRC, as effective screening can prevent it by detecting and removing premalignant lesions. Recent studies suggest that an altered gut microbiota may confer susceptibility to certain types of cancer. Interestingly, the gut microbiota of patients with adenomas or CRC differs from that of healthy individuals. This study aims to identify gut microbiome biomarkers in faecal samples associated with CRC and/or high-risk adenomas to improve early detection.

Gender: All

Ages: 40 Years - 74 Years

Updated: 2026-05-14

1 state

Colorectal Cancer Screening
Colorectal Cancer (CRC)
Microbiome
RECRUITING

NCT06734156

CARE-CRC: Microbiome Insights and Correlations for Risk and Outcomes in Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths globally, with increasing incidence rates. While predominantly affecting older adults, CRC cases among individuals under 50 (early-onset CRC, or EoCRC) are rising. This age group rarely undergoes routine screening, resulting in delayed diagnoses and more advanced disease at presentation. In the USA, EoCRC accounts for 10% of CRC cases and is the leading cause of cancer-related deaths in men under 50. Despite the increase in EoCRC incidence, the causes remain unclear. Only 25% of cases have a CRC family history, suggesting environmental factors. Diets low in fibre and rich in fat and red meat, obesity, alcohol consumption, sedentary lifestyle, stress, and chronic inflammation of the GI tract are estimated to account for 70-90% of CRC risk. According to the World Cancer Research Fund, 47% of all CRC cases could be prevented through lifestyle changes, particularly in diet and physical activity. These lifestyle factors are also strongly linked to changes in the gut microbiome, which differs markedly between CRC patients and healthy individuals. The microbiome may influence tumour development by producing metabolites that regulate immune responses or create anti-tumour environments. Thus, the gut microbiome is a promising target for early CRC detection and prevention. This study aims to develop a non-invasive, microbiome-based diagnostic tool for CRC, identifying biomarkers to improve early detection, personalise treatment, and reduce healthcare costs.

Gender: All

Ages: 40 Years - 74 Years

Updated: 2026-05-12

1 state

Colorectal Cancer (CRC)
Microbiome
Early Onset Colorectal Cancer
RECRUITING

NCT07311083

Feasibility of a Lifestyle Intervention for Women With Triple-negative Breast Cancer Under Neoadjuvant Immunotherapy

Triple-negative breast cancer (TNBC) is considered a tumor with a high risk of recurrence and metastasis and requires aggressive systemic therapy combining immunotherapy and chemotherapy. If the therapy leads to complete remission (pCR), this is prognostically beneficial for patients. Studies demonstrating the influence of the microbiome on the development of cancer and on the efficacy and toxicity of immunotherapy and chemotherapy underscore the potential of targeted nutritional interventions. Current data from microbiome research indicate that a high-fiber, gut-healthy diet modulates the microbiota in such a way that the response to and toxicity of immunotherapy and chemotherapy could be improved. The aim of this project is to translate these findings into clinical care. The study will investigate whether an online integrative oncology group training program with mind-body elements supports and is feasible for the implementation of a high-fiber diet in patients with TNBC undergoing neoadjuvant immunotherapy and chemotherapy. The program will be compared with a control group that receives a flyer with nutritional recommendations. If the feasibility of this complementary medicine approach can be demonstrated, a confirmatory study is planned to investigate the expected effect on the pathological complete remission of TNBC.

Gender: FEMALE

Ages: 18 Years - 75 Years

Updated: 2026-05-08

1 state

Microbiome
RECRUITING

NCT05514899

Effects of Cannabidiol and Tetrahydrocannabinol on Microbiome and Neuroinflammation in HIV

This study has the potential to contribute to a more complete understanding of the independent and combined effects of cannabis use and HIV on the brain and on inflammation. Such knowledge may inform future strategies for treating brain disease and inflammation. Participants will be randomly assigned to one of two groups, both of which will receive the same treatment in a different order over a period of about 6 weeks. The visits include physical examinations, blood tests, and other procedures designed to monitor subject safety and measure the effects of the study drug.

Gender: All

Ages: 21 Years - 70 Years

Updated: 2026-05-01

1 state

HIV
Cannabis
THC
+3
RECRUITING

NCT06566898

Monitoring of Antimicrobial Resistance Based on Metagenomics Analyses in Pneumonia Patients

Monitoring of antimicrobial resistance (AMR) based on metagenomics analyses in pneumonia patients is critical for optimizing clinical diagnosis and treatment and improving clinical prognosis. This study is designed to ask the following key questions: 1. What is the microbiome maps of patients with severe pneumonia and mild pneumonia ? 2. How many pathogen resistance genes are carrying in severe pneumonia and mild pneumonia ? 3. What is the genetic diversity of key pathogens detected in severe pneumonia and mild pneumonia during 2019-2025?

Gender: All

Updated: 2026-04-23

1 state

Pneumonia
Next-generation Sequencing
Microbiome
+1
RECRUITING

NCT07532629

Microbiome and Metabolome Profiles in Couples Undergoing IVF and Reproductive Outcomes

This prospective observational cohort study investigates the role of the microbiome and metabolome in couples undergoing in vitro fertilization. Biological samples will be collected from both female and male partners, including semen, vaginal, and blood samples, to characterize microbial composition and metabolic profiles. The study aims to examine how these biological profiles are associated with reproductive outcomes such as fertilization, pregnancy, miscarriage, and live birth. Participants will be followed longitudinally, and reproductive and obstetric outcomes will be obtained through linkage with national health registers.

Gender: All

Ages: 18 Years - 40 Years

Updated: 2026-04-16

Infertility
Assisted Reproductive Technology
Pregnancy Complications
+3
ACTIVE NOT RECRUITING

NCT05123612

Maternal & Offspring Microbiome Study

The purpose of the study is to learn how different dietary interventions affect microbiota diversity in pregnant women and the transmission of microbiota to their infants during pregnancy, birth, and postpartum.

Gender: FEMALE

Ages: 18 Years - 50 Years

Updated: 2026-04-06

1 state

Pregnancy Related
Microbiome
Immune Function
+1