Gut Microbiome

This study builds on the knowledge that fasting provides metabolic health benefits and that prebiotic interventions can enhance the gut microbiome's metabolic output to likewise improve host health. Whether long-term fasting and dietary fibre interventions could be combined to achieve synergistic improvements in host metabolic health is however unknown. The goal is to provide a proof of concept in a human trial that supplementing 10±4 days fasting with dietary fibre synergistically improves metabolic outcomes via gut microbiome-mediated effects. To assess this, we aim to analyse gut microbiome changes, functional outputs, and key metabolic markers such as butyrate production, glycaemic control and ketosis. The randomised controlled trial includes 75 participants and has two arms: one involving fasting with fibre supplementation (n = 50) and one involving fasting without fibre supplementation (n = 25). All participants will undergo a fasting period of 10±4 days according to the Buchinger Wilhelmi protocol, followed by a stepwise reintroduction of food of up to 4 days. As dietary fibre we will use maize-derived resistant starch type IV, selected based on its ability to stimulate beneficial gut microbes like Oscillibacter and corn starch as placebo. Two main visits will be conducted: before and at the end of the fasting period. During these visits, blood and stool samples will be collected, and questionnaires will be completed. Additionally, daily measurements of anthropometric parameters and well-being will be recorded. Stool samples will also be collected one month afterwards as a follow-up. Participants' metabolic health will be evaluated through various clinical parameters (e.g., body measurements, blood pressure, glycaemic control, ketones, well-being). Additionally, multi-omics data, including metagenomics and metabolomics, will provide insight into the composition of the microbiome, as well as its outputs and functions. Furthermore, the effects of fasting on extracellular vesicles in blood will be explored.

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.

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.

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 intervention study is to investigate the effects of daily egg intake on markers of gut health, high-density lipoprotein (HDL), metabolic, and immune cell profiles in adults with body mass indexes (BMI) in normal and obesity ranges. This study further aims to determine whether egg effects are associated with baseline gut microbiome profiles, and whether egg effects are different between males and females and by BMI status. The study will address the following objectives: Objective 1: Evaluate the effects of daily egg white vs. whole egg intake on gut health, microbiome, and metabolome profiles. Objective 2: Evaluate the effects of daily egg white vs. whole egg intake on HDL composition and function. Objective 3: Evaluate the effects of daily egg white vs. whole egg intake on immune profiles and function in culture (ex vivo). Participants will be asked to consume egg whites and whole eggs on a daily basis for 4-weeks each, and avoid eating eggs for a total of 8 weeks at different points in the study. Participants will be asked to complete surveys about dietary intake and physical activity, as well as provide blood and stool samples throughout the course of the study.

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).

This is a 12-month, 2-arm randomized controlled trial (n=150) examining whether toddlers randomized at 12 months of age to 1.5 cup-equivalents/day of cow's milk-based dairy versus oat milk-based dairy, and followed to 24 months, have better growth, sleep, neurocognitive, and gut microbiome outcomes.

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.

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.

This randomized, double-blind, placebo-controlled exploratory study will evaluate the effects of daily probiotic supplementation on gut barrier function, immune-related markers, and well-being in healthy adults with mild to moderate perceived stress. 50 participants will be randomly assigned to receive either a probiotic supplement or placebo for 8 weeks. Blood and stool samples will be collected before and after the intervention to assess markers of gut barrier function, intestinal inflammation, gut microbiome composition, short-chain fatty acids, and immune function. Participants will also complete questionnaires on stress, quality of life, mood, digestive symptoms, and bowel habits. Safety will be evaluated throughout the study by monitoring adverse events and vital sign assessments.

Study Summary Nearly half (47%) of people with end-stage kidney disease (ESKD) whose kidney function is restored after kidney transplantation experience chronic pain compared to 19% of adults in the US general population. Pain is associated with comorbid fatigue, depression and anxiety, and withdrawal from usual physical and social activities; resulting in an inability to participate in and enjoy life. Severe pain can result in nonadherence to immunosuppression and treatment protocols and result in an increased risk of rejection, graft loss, and mortality. The role of symbiotic microbes (microbiota) in the gastrointestinal tract, and their functional genes (microbiome), is well established in diseases involving pain. Diet and stress play a major role in synthesis of signaling molecules critical to immunologic, metabolic, and endocrine pathways regulating chronic pain. Dietary patterns change dramatically after transplantation, as recipients move from a restricted "renal" diet to a regular diet, often resulting in increased consumption of foods high in sugars and fat. Moreover, psychological stress significantly impairs the function of the microbiome, initiating biological pathways involved in pain, leading to a disproportionate pain burden. Because the microbiome, serum metabolites, and pain are dynamic, our novel investigation will employ a prospective repeated measures design to interrogate the dynamic temporal relationships between the microbiome, metabolites associated with pathways regulating pain, transplantation factors (e.g. immunosuppression, kidney function), changing dietary patterns, and perceived stress, on pain scores before and after kidney transplantation. The investigators posit the gut microbiome, and its byproducts, may partially explain the underlying biological mechanisms of pain Interference in kidney disease. The investigators will address three aims: 1) To determine differential dynamic temporal relationships between microbial composition/functional genes and circulating serum metabolites in KTRs with pain vs no pain, 2) To determine the moderation effects of diet and perceived stress on dynamic temporal relationships between microbiome features, serum metabolites, and pain scores among KTRs, and 3) To use machine learning algorithms to identify host-microbial interactions that are causally linked to pain interference among KTRs. Because kidney function is restored, the kidney transplant model is powerful to study the longitudinal relationships between the microbiome, circulating metabolites and chronic pain in people with ESKD to develop patient-centered interventions to treat pain across the spectrum of CKD.

This project uses a hybrid trial design to evaluate two biomedical interventions targeting the gut-brain axis. One intervention is portable Transcutaneous Vagus Nerve Stimulator, tVNS, that is hypothesized to stimulate the autonomic nervous system, resulting in decreased inflammation and improved cognition. The second intervention is a probiotic supplement intended to replace gut bacteria that are associated with dysbiosis in persons with HIV and alcohol consumption.

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.

The gut microbiota is currently attracting increasing attention from the scientific community and also from the general public, as evidence of its role in human physiology has been highlighted. Microbial signatures have also been associated with various pathologies (e.g. obesity, diabetes, gastrointestinal disorders, neurodegenerative diseases), but the causality of these associations is still uncertain. Among the factors that may influence the composition of the gut microbiota (e.g. lifestyle, hygiene, medication, genetics, environment), nutrition would a major role. The major changes in lifestyle and diet observed over recent decades are strongly suspected of disrpting the host-gut microbiota balance. In addition to their nutrient content, our diets also contain other bioactive compounds (e.g. polyphenols) and raise new issues (e.g. temporal structure of diets, food processing, presence of additives or contaminants such as pesticide residues, intake of dietary supplements, dietary exclusions, glycemic index) that is necessary to take into account. Thus, it is mandatory to explore and characterize in a more precise way, within large samples consisting of individuals with varied characteristics, the way in which the composition of the gut microbiota is influenced by the host's diet and its health consequences. The aim of this research is therefore to study the links between nutrition, gut microbiota profiles and health. To do this, the research will implement large-scale stool sample collection from participants in the NutriNet-Santé cohort ("Nutrinautes"), thus constituting a "microbiota" sub-cohort. A target of N=10,000 participants in the NutriNet-Santé cohort will be recruited on a voluntary basis. A selection will then be made among Nutrinautes willing to participate in the research (which may be more numerous than necessary) to maximize the diversity of profiles. Participants will be informed of their selection or non-selection by e-mail. A second stool sample will also be collected 2-3 months after the first for a sub-sample of N=300 to assess intra-individual variability in microbiota profiles. The selected participants will receive a stool self-sampling kit with detailed instructions by post to their home address. The pseudonymized samples will be returned by mail by the participant to the processing laboratory, which will determine their gut microbiota characteristics by 16S rDNA sequencing and/or " shotgun " sequencing. The gut microbiota profiles will then be analyzed in a pseudonymised manner in association with diet and health, using data collected as part of the NutriNet-Santé cohort follow-up (e.g. food consumption, prevalence and incidence of pathologies, biological data, anthropometric characteristics, medication intake, socio-demographic characteristics, lifestyle).

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.

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.

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.

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 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.

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