Gut Microbiome

Pregnancy is a critical window for metabolic health, and early changes in blood sugar regulation can increase the risk of gestational diabetes mellitus (GDM), which affects both maternal and infant health. At the same time, the maternal gut microbiome changes throughout pregnancy and may play a role in glucose metabolism and insulin resistance. Kefir, a fermented milk drink containing beneficial bacteria and yeasts, may be a simple dietary strategy to support metabolic health during pregnancy, but its role in preventing GDM has not been well studied. This study will test whether drinking kefir daily from mid-pregnancy until routine GDM screening can improve glucose and insulin regulation, reduce the incidence of GDM, and modulate the maternal gut microbiome and metabolites, among other outcomes. Pregnant individuals will be randomly assigned to either a kefir group or a control group receiving usual prenatal care. Researchers will collect blood glucose and insulin measures, dietary information, stool samples, and body composition data across pregnancy and postpartum to evaluate metabolic and microbiome-related changes. As one of the first studies to examine kefir as an early pregnancy intervention for GDM prevention, this study will help clarify whether a practical, food-based approach can improve maternal metabolic health. The findings may support future nutrition strategies aimed at reducing GDM risk and improving pregnancy outcomes.

The purpose of this study is to explore how the dietary supplement L-Phenylalanine affects the production of the metabolite phenylpropionic acid (PPA) and changes fungal populations of the gut microbiome.

The XCVD study investigates the influence of sex hormones on the composition of the gut microbiome and the possible emergence of cardiovascular risk factors. It will follow 200 healthy transgender individuals for five years during their hormone replacement therapy (HRT) and analyze them for the possible emergence of cardiovascular risk factors in relation to changes in the gut microbiome, metabolome, and immunome. We would also like to phenotype cardiovascular disease.

Dengue infections are imposing an increasing global burden of disease, particularly in tropical countries such as Bangladesh. The World Health Organization (WHO) has identified Dengue virus as a priority pathogen for the development of medical counter measures because of the high risk of it causing a Public Health Emergency of Intenational Concern (PHEIC). Warning signs for severe dengue, associated with mortality, include gastrointestinal features including abdominal pain, vomiting, and diarrhoea. Multiple alterations may occur in in the gastrointestinal tract that could lead to damaging of the gastrointestinal wall and gut leakage, the translocation of gut metabolites into the bloodstream. Study team hypothesize that gut leakage initiates inflammatory processes underlying the further development of severe dengue, including features associated with plasma leakage. This study aims to investigate intestinal barrier dysfunction (gut leakage) in dengue infection by detecting the translocation of gut-derived bacteria and their products (Lipopolysaccharides, LPS binding protein, sCD14, I-Fatty Acid Binding Protein) into the bloodstream. Study team will recruit hospitalized adult dengue patients (18 years and older) presenting with warning signs or severe disease in a tertiary care public hospital at Chattogram, Bangladesh. Circulating biomarkers indicative of gut permeability and microbial translocation will be measured to assess their presence and association with disease severity. Abdominal ultrasonography will be performed to characterize gastrointestinal alterations and determine their correlation with biochemical markers of gut leakage and clinical severity. In addition, study team will analyze the gut bacteriome from stool/ rectal swab of these patients to explore whether dengue infection induces compositional changes in intestinal microbiota and whether such alterations are linked to gut leakage or disease progression.

AGEWISE is an observational study that aims to understand how changes in gut microbiome are related to hormonal changes during women's ageing, particularly across the different stages of menopause. The study will include healthy women aged 40 to 64 years living in Portugal, who will provide stool and blood samples and complete questionnaires about their health, lifestyle, diet, and menopausal symptoms. Researchers will study the gut microbiome together with hormone levels and markers of inflammation to better understand how menopause affects long-term health and to support the development of improved prevention strategies for women.

Toddlerhood (ages 2-3) is a critical window when the gut microbiome is still developing and eating habits are being established. Yet, many Canadian toddlers eat diets high in sugar and salt, which may affect long-term health. This study will test whether a MED diet can improve dietary inflammation, gut health, and body composition in toddlers and whether a tailored nutrition education program for parents can help families maintain healthy eating patterns. In this study, toddlers will be randomly assigned to a 3-week MED diet or their usual diet. Families in the MED diet group will receive free meal boxes for the 3 weeks, plus guidance from a nutrition researcher through a structured education program. The standard diet group will continue their regular diet with general nutrition advice. Researchers will collect dietary information, body composition assessments, and stool samples to measure gut microbiome composition and metabolites. This first study of a controlled diet intervention in toddlers, combining behavioral support, high-quality food provision, and advanced gut microbiome analysis, will help understand how early diet shapes lifelong eating habits and health, guiding public health strategies and precision nutrition approaches to prevent chronic disease from early life.

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).

The goal of this clinical trial is to learn if Goat Milk-Derived Formula Alternatives (GMDFA) are safe and effective for infants who are unable to be exclusively breastfed. It will also study growth patterns, biological markers, and gut microbiome differences among infants receiving GMDFA, undiluted goat milk, or breast milk. The main questions it aims to answer are: 1. Do infants receiving GMDFA show similar growth patterns to those who are breastfed? 2. Are biological markers of gut health and nutrition (such as calprotectin, lipocalin-2, CRP, and claudin) comparable between the groups? 3. How do feeding types (GMDFA, goat milk, or breast milk) influence the infant gut microbiome composition, metabolic pathways, and lipid profiles? 4. Is GMDFA a safe and nutritionally adequate feeding option for infants unable to be exclusively breastfed? We will compare GMDFA, undiluted goat milk, and breast milk (reference group) to evaluate infant growth, gut health, and metabolic outcomes. Participants will: Be randomly assigned to one of three feeding groups: GMDFA, undiluted goat milk, or breastfed Attend regular follow-up visits for growth measurements and sample collection (blood, stool, and breast milk where applicable) Have feeding practices monitored and recorded through caregiver interviews and feeding logs Additional Analyses: Microbiome analysis: to identify gut bacterial diversity and composition across feeding groups Metagenomic analysis: to explore functional genes and metabolic pathways related to nutrition and gut health Lipidomic analysis: to assess differences in lipid and fatty acid profiles in breast milk, goat milk, and infant samples

The purpose of the study is to determine the effectiveness of wild blueberries on cardiovascular health, cognitive function, and gut microbiota composition in non-Hispanic Black and White adults with elevated blood pressure.

The goal of this pilot study is to examine the feasibility and effects of an 18-month intervention diet compared to an active control diet (standard diet) in those living with Parkinson's Disease (PD), without dementia. Research has shown that eating components of Mediterranean diets are associated with a 30% lower risk to develop PD and a 40% lower mortality rate in those living with PD. Diet may influence the gut and microbiomes, thus may affect PD risk and progression. This study will examine how easy it will be to adhere to a certain type of diet for 18 months and what changes may occur in the gut microbiome and in PD symptoms on a specific diet during that time. The study will involve in-person study visits at UBC as well as online diet coaching sessions and online group cooking classes over Zoom. This is a randomized study, meaning that participants will be assigned by chance to either the Mediterranean-style diet group or the standard diet group for the duration of the 18 months. This pilot study will also examine recruitment rates and retention, in order to prepare for a larger future study.

The goal of this study is to learn how different amounts of supervised indoor cycling training change gut health (gut bacteria, the substances gut bacteria make, and the gut barrier integrity), and how these changes relate to changes in fitness, muscle health, and signs of doing too much training (a state called 'overreaching'). The study includes healthy, recreationally active men aged 18 to 45 years. The primary questions, for which the study is powered (sufficient participants included), are: 1. Does moderate load training change blood and faecal levels of butyrate (a short-chain fatty acid made by gut bacteria) after eight weeks compared with a control group? 2. Compared to moderate load training, do higher training loads lead to different responses in blood and faecal levels of butyrate? Researchers will compare: * A control group that does not complete structured training; * A moderate-load training group that completes eight weeks of supervised cycling (4x/week); * A high-load training group that completes four weeks of moderate-load training followed by four weeks of higher training load (twice the number of training sessions). Participants will: * Be randomly assigned to one of the three groups; * Complete 8 weeks of supervised indoor cycling sessions if assigned to a training group; * Complete four study assessment periods (baseline, after week four, after week eight, and after a short taper (rest period); * Provide blood, stool, skeletal muscle, urine, saliva, and breath samples during the assessment periods; * Complete fitness and performance tests and questionnaires during the assessment periods.

This study will explore how a natural food ingredient called oligofructose affects blood glucose levels, lipid profiles, inflammation biomarkers, and gut bacteria in Saudi adults with type 2 diabetes. Oligofructose is a type of dietary fiber found in foods such as onions, garlic, and bananas. It is known to help the growth of "good" bacteria in the intestine, which may improve digestion and metabolism. A total of 100 adults (50 with type 2 diabetes and 50 without diabetes) will take part in this research. Participants will be randomly assigned to receive either oligofructose or a placebo twice daily for 12 weeks. Blood tests will be done at the beginning and at weeks 4, 8, and 12 to check changes in blood glucose, lipid profiles, and inflammation. The goal of this study is to find out whether adding oligofructose to the diet can help people with diabetes improve their blood glucose control, reduce inflammation, and support a healthier balance of gut bacteria.

The goal of this clinical trial is to learn whether microbiome analysis, education, and personalized recommendations can improve gut health and reduce early markers of immune-related conditions in infants aged 0-3 months delivered via Cesarean section. The study aims to determine whether these interventions can increase beneficial bacteria, decrease C-section-associated microbiome signatures, reduce opportunistic pathogens, and improve functional potential for HMO digestion and SCFA production. The study also seeks to assess whether improvements in microbiome composition are associated with a reduced prevalence of early atopic symptoms. Researchers will compare three groups: a full intervention arm that receives microbiome reports, coaching, personalized recommendations, and educational materials; a limited intervention arm that receives simplified reports and basic recommendations; and a control arm that receives no results until study completion. This design allows evaluation of both a comprehensive intervention and a more scalable, minimal-results model. Participants will: 1. Provide six microbiome stool samples over a 24-month period. 2. Provide additional small stool samples at two timepoints for exploratory metabolomic analysis. 3. Receive microbiome reports and guidance according to their assigned study arm. 4. Complete surveys on infant health history, symptoms, diet, and environmental exposures. 5. Participate in standardized eczema assessment(s) administered by a Nurse Practitioner and evaluated by a Pediatric Allergy Specialist if any symptoms are reported. This study seeks to demonstrate that targeted microbiome support can positively shift gut microbial development in C-section infants and may reduce risks linked to the early stages of the atopic march. Findings may inform scalable strategies for delivering microbiome-based support in early life and improve long-term health outcomes for this high-risk population.

The objective of the proposed research is to determine the effects of fresh mango consumption on gut microbiome, and its relationship with skin health, sexual and mental health in relatively healthy adults.

The goal of this clinical trial is to evaluate the effects of blackcurrant (BC) supplementation on changes in bone density and gut microbiome composition in postmenopausal females.

A national data registry of patients receiving fecal microbiota transplantation (FMT) or other gut-related-microbiota products designed to prospectively assess short and long-term safety and effectiveness

To test how two weeks of curcumin supplementation would cross the blood brain barrier (BBB) and attach to amyloid beta proteins, to assess the feasibility (safety and bioavailability), and to explore the resulting abundance/composition of gut microbiota.

The Investigators will recruit 35 participants with acute SCI (within 6 weeks of injury) Fasting blood collection and bowel function survey will be conducted 3 times: at baseline \[within 6 weeks of injury\], 6, and 12 months after SCI. Stool will be collected for gut microbiome analysis 3 times.

The goal of this clinical trial is to learn how the antifungal drug fluconazole affects the gut microbiome and immune system in healthy volunteers. The main questions it aims to answer are: * Does fluconazole change the gut bacteriome and mycobiome composition after 14 days of treatment? * How long do these changes last (4 weeks and 6 months after treatment)? * Does fluconazole affect the body's immune responses, such as blood cell activity and antifungal antibodies? Researchers will compare two groups: participants who take fluconazole for 14 days and participants who receive no intervention. Participants will: * Either take one fluconazole tablet (200 mg) daily for 14 days, or receive no treatment * Provide stool samples and blood samples at several timepoints * Return for follow-up visits up to 6 months after treatment This study is conducted at Amsterdam UMC, location AMC, with a planned enrollment of 50 healthy male volunteers aged 18-35 years.

The goal of this single-arm feasibility, pilot study is to assess the feasibility, acceptability, and potential effectiveness of the Herbs and Spices Nutrition Education Program (HSNP-focusing on incorporating herbs and spices into the diet for adherence to the DGA's) for determining the scalability of implementing this intervention for a larger scale, more comprehensive study The main questions it aims to answer are: * What is the feasibility and acceptability of incorporating herbs and spices into the diet along with DGA-focused nutrition education through the HSNP in college students with poor dietary quality? * What are the preliminary effects of the HSNP on dietary intake/quality, cardiometabolic, and gut health in college students with poor dietary quality? * What are the barriers associated with HSNP implementation in college students with poor dietary quality? Participants will: * Be asked to come to the study site initially for a Screening Study Visit to confirm eligibility. * Be asked to come the clinical study site for a Pre-HSNP and Post-HSNP Study Visit (one week prior starting the HSNP and after week 6 of completing the HSNP) for assessments of cardiometabolic and gut health. * Be asked to come to the Nutrition Center for weeks 0 and 3 of the HSNP, where they will receive education on the Dietary Guidelines for Americans and the health benefits of herbs and spices, have a sensory evaluation of foods, be provided budget-friendly recipes and resources, and given take-home herbs, spices, and supporting materials * Be asked to complete 3-Day Food Records throughout the 6 week study period for assessment of dietary quality (4 total)

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.

The goal of this clinical trial is to assess whether a peri-operative intervention with nutritional immune modulating intervention (Ensure Surgery Immunonutrition shake) has beneficial effects on the complex interplay between gut microbiome, systemic inflammation and malnutrition that is commonly present in advanced heart failure and the adverse events associated with left ventricular assist device (LVAD) placement in hospitalized advanced heart failure patients awaiting LVAD implantation. The main questions it aims to answer are: * Will pre-surgical supplementation with Ensure Surgery affect gut microbial composition and levels of inflammation among heart failure patients undergoing LVAD implantation? * Will pre-surgical supplementation with Ensure Surgery affect post-surgical morbidity (e.g., infections, intensive care unit length of stay (LOS)) and mortality? Participants will be evaluated for malnutrition and will be given Ensure Surgery Immunonutrition shake to drink in the days preceding their LVAD surgery. Blood and stool samples will be collected at prespecified timepoints before and after surgery. Researchers will compare malnourished participants drinking Ensure Surgery 3/day with well-nourished participants randomized to drink either 1/day or 3/day to see if any of the above supplementation strategies change the gut microbial composition, levels of inflammation, and post-surgical morbidity and mortality.

The goal of this clinical trial is to learn if daily avocado intake can improve growth and brain and gut health in infants. The main questions it aims to answer are: Does daily eating of avocados change which microbes live in the infant's gut? Does daily avocado intake improve infant motor skills and cognitive development? Researchers will compare avocado intake to standard of care (no or limited avocado intake) to see if regular avocado intake from 6-12 months of life influences gut and brain health. Participating mothers/guardians and their infants will: Parents will provide avocado or no avocado to their infant every day for 6 months starting around 6 months of infant age. Parents will allow study staff to visit participant homes to collect data via surveys and observations and measure infant growth. Parents will swab soiled infant diapers for gut microbe measures. Parents will keep a diary of the infant's avocado consumption and acceptance of the food. Parents will record their infant's dietary intake

The overall objective of this clinical trial is to compare the effects of a cranberry-based product to a placebo-control product on vaginal and GI microbiome outcomes and associated participant reported outcomes in generally healthy pre-menopausal women

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.