Clinical Research Directory

Early Avocado Exposure on Development and the Gut Microbiome in American Hispanic Infants

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 Impact of Overnight Active Temperature Regulation on the 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.

Investigation of Egg Intake and the Relationship Between Gut Microbiome, Metabolic, and Immune Profiles

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.

Feasibility and Potential Efficacy of Herbs and Spices for Improving Dietary Quality in College Students: A Pilot Study

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 (within two weeks prior to 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 1 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)

Combining Fasting and Fibre Interventions to Optimise Their Gut Microbiome-mediated Health Benefits

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.

Diabetes, Insulin, Gut, Enteric Supplementation Trial

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.

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).

Mediterranean Diet Uptake and Nutrition on Child Health, Inflammation, and Early-life Symbiosis (MUNCHIES) Study

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.

Tiny Tummies - A Milk Study

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.

A Study to Explore the Role of Gut Flora in COVID-19 Infection

This study seeks to determine whether the virus which causes COVID-19, SARS-CoV-2, is shed in the stools of patients who are infected.

A Non-Interventional Pilot Study to Explore the Role of Gut Flora in Disease

This study seeks to correlate microbiome sequencing data with information provided by patients and their medical records.

Intermediate Wheatgrass Products and Gut Health

This study will evaluate the effect of daily consumption of intermediate wheatgrass-based products on measures of gut health compared with whole wheat-based products in healthy adults with traditional western fiber intake. Participants will first complete screening, stool sample collection, and the Diet History Questionnaire III. Participants with dietary fiber intake greater than 12g/1000 calories per day will complete the study after baseline procedures. Participants with dietary fiber intake of 12g/1000 calories per day or less will enter a randomized crossover dietary intervention. During the intervention, participants will consume intermediate wheatgrass-based products and whole wheat-based products in randomized order. Each intervention period will last 2 weeks and will be separated by a 2-week washout period. The primary outcome is change in Gut Microbiome Wellness Index. Gastrointestinal symptom scores will also be assessed.

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.

Effects of Complementary Feeding on Infant Growth and Gut Health

This study plans to learn more about how consuming different foods during the time of early complementary feeding (\~5 to 12 months) affects growth and the development of bacteria living inside your baby's gut through school-age. The results from this study will potentially help to support future recommendations and dietary guidance for infant feeding practices. The three primary aims include: Aim 1. Identify the impact of dietary patterns with different protein-rich foods on infant growth. Aim 2. Identify the impact of dietary patterns with different protein-rich foods on infant gut microbiota development. Aim 3. Identify gut microbial taxa and genes that affect infant growth.

Assessment of Microorganisms and Host Response In Liver Diseases

The normal human gut is home to millions of microbes including bacteria, fungi, and viruses, collectively forming the gut microbiota, which exists in harmony within us. Much research is still required to fully understand the contribution of microbes resident in the large intestine in liver diseases. The liver receives blood from the gut carrying all the necessary nutrients needed for our body but also has to deal with toxins derived from the microbes residing in the intestines. The gut microbiota is altered in liver disease. We still do not know clearly how this change impacts liver function and the health of liver patients. The purpose of our study is to answer this question by assessing the gut microbiota using modern microbiological and molecular methods. By studying the alterations in the gut microbiota in patients with liver disease we can understand how they affect our immune system and metabolism. This will help design novel medicinal products to prevent and treat liver disease.

Wild Blueberries for Gut, Brain, and Heart Health in Adults With High Blood Pressure

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.

Effects of Probiotic Supplementation on Gut Health, Immune Response, and Well-Being

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.

The Gut Microbiome and Serum Metabolites as a Biological Mechanism Underlying Pain in Kidney Transplantation

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.

The Path Study: Cognitive and Inflammation Targeted Gut-brain Interventions in Alcohol; Probiotics, Alcohol, Transcutaneous Vagus Nerve Stimulation, and HIV Study

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.

Gut Leakage' in Dengue

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.

Nutrition, Gut Microbiota and Health : Feces Sample Collection in NutriNet-Santé Participants

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).

Blackcurrants Modify Gut Microbiota and Reduce Osteoporosis Risk in Postmenopausal Females

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.

Understanding the Efficacy of Dietary Supplement on Fungal Mycobiota in Healthy Volunteers: A Pilot Study

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.

Sex-differential Host-microbiome CVD Risk - A Longitudinal Cohort Approach

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.