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Completed

NCT Number: NCT04804319

Interactions Between Diet, Microbiome and Abiotic Conditions in the Gut

The aim of this study is to explore the interplay between environmental (abiotic) factors in the gut and the gut microbiota composition, diversity and metabolism. Such insights could help us understand personal responses to diets and be a first step towards personalized dietary recommendations targeting the gut microbiome.

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Key information

Conditions

Diet, Healthy Metabolic Disease Metabolic Diseases Nutritional and Metabolic Diseases

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Observational

Primary location

University of Copenhagen, Department of Nutrition, Exercise and Sports

Copenhagen, 1958, Denmark

About this study

The study is a 9-day trial including 85 healthy adults in age between 18 and 75. The participants will throughout the trial register their dietary intake, gastrointestinal symptoms including stool frequency and Bristol stool scale, physical activity, and medicine and supplements intake. Participants will on day 3 and day 5, respectively, consume sweet corns to estimate intestinal transit time by the time it takes sweet corn to travel through the gastrointestinal system. Furthermore, the participants will collect daily urine and stool samples.

On day 2 and day 9, participants will arrive fasting at the department in the morning and have their anthropometry, breath hydrogen and methane levels measured, and a blood sample will be collected from each participant.

The first visit (day 2) also includes a standardized meal test (rye bread, butter, jam, egg, and yogurt with nuts and berries) and intake of paracetamol (250 mg). Subsequently, the participants will stay at the department for the following 6 hours and have their postprandial breath hydrogen and methane measured and urine collected at specific intervals.

Moreover, a sub-set of the participants will on the first visit (day 2) immediately after intake of the standardized meal swallow a single-use gastrointestinal SmartPill capsule, which will monitor their gastrointestinal pH, transit time, temperature and pressure.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 18.5-30.0 kg/m2 BMI
  • Willing to daily collect a urine and stool sample at home and able to store them in their own freezer in a provided containers throughout the 9-days trial
  • Willing to eat sweet corn and report corn-intestinal transit time questionnaire
  • Willing to record 9 days dietary intake and defecation pattern
  • Willing to have blood samples drawn two times
  • Owns a device with access to the internet and is willing to use myfood24 platform
  • Known ability to tolerate paracetamol and willing to consume ½ paracetamol tablet dissolved in water (250mg)
  • Willing to eat rye bread, butter, jam, egg, yoghurt, berries and nuts

Exclusion criteria

  • Any condition that makes the project responsible researcher to doubt the feasibility of the volunteer´s participation
  • Pregnant or lactating women
  • Suffering from inflammatory bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO) or inflammatory bowel diseases (IBD)
  • Intake of antibiotics, diarrhea inhibitors and laxatives ˂ 1month
  • Current chronic or infectious diseases
  • Diagnosis of diabetes
  • History of cancer within the past 5 years (except adequately-treated localized basal cell skin cancer or in situ uterine cervical cancer)
  • Frequent intake of painkillers or other medication (mild antidepressants and contraceptive pills are allowed)
  • Concurrent participation in another trial

Additional exclusion criteria for the SmartPill sub-study:

  • Intake of medications potentially altering gastric pH (proton pump inhibitors, histamine receptor antagonists, antacids)
  • Intake of medications potentially altering the gastrointestinal motility (prokinetics, antiemetic agents, anticholinergic agents, narcotic analgetics, nonsteroidal anti-inflammatory drugs)
  • Dysphagia

Treatment and study plan

9-days habitual diet

Other

9-days study with habitual diet including one standardized breakfast on a single day

Primary outcomes

  1. Faecal pH vs gut microbial saccharolytic/proteolytic metabolism

    Time frame: Day 1-9

    We test whether faecal pH is positively associated with microbial-derived proteolytic metabolites (i.e. p-cresol sulfate and phenylacetylglutamine) in urine and negatively associated with microbial-derived saccharolytic metabolites in faeces (i.e. acetate, butyrate and propionate)

Secondary outcomes

  1. Abiotic factors vs faecal metagenomic profile

    Time frame: Day 1-9

    We test whether day-to-day variations in abiotic factors (faecal and/or intestinal pH, faecal redox potential, intestinal transit time and substrate availability) are associated with changes in the faecal microbiome

  2. Abiotic factors vs faecal metabolome

    Time frame: Day 1-9

    We test whether day-to-day variations in abiotic factors (faecal and/or intestinal pH, faecal redox potential, intestinal transit time and substrate availability) are associated with changes in the faecal metabolome

  3. Abiotic factors vs urine metabolome

    Time frame: Day 1-9

    We test whether day-to-day variations in abiotic factors (faecal and/or intestinal pH, faecal redox potential, intestinal transit time and substrate availability) are associated with changes in the urine metabolome

  4. Abiotic factors vs blood metabolome

    Time frame: Day 2 and 9

    We test whether day-to-day variations in abiotic factors (faecal and/or intestinal pH, faecal redox potential, intestinal transit time and substrate availability) are associated with changes in the blood (serum) metabolome

  5. Abiotic factors vs microbial-derived metabolites

    Time frame: Day 1-9

    We test whether day-to-day variations in abiotic factors (faecal and/or intestinal pH, faecal redox potential, intestinal transit time and substrate availability) are associated with changes in diet-derived microbial metabolites in blood/urine/faeces, including short-chain fatty acids, secondary bile acids, phenolic and indolic compounds, branched-chain fatty acids, trimethylamine N-oxide, hippuric acid, urolithin, and enterolactone

  6. Faecal metagenomics profile vs metabolome

    Time frame: Day 1-9

    We test whether day-to-day variations in the microbiome are associated with changes in diet-derived microbial metabolites in blood/urine/faeces, including short-chain fatty acids, secondary bile acids, phenolic and indolic compounds, branched-chain fatty acids, trimethylamine N-oxide, hippuric acid, urolithin, and enterolactone

Other outcomes

  1. Faecal microbiome

    Time frame: Day 1-9

    Determination of the variation in the intra- and inter-individual microbiomes in all faecal samples collected from day 1 to day 9

  2. Faecal metabolome

    Time frame: Day 1-9

    Changes in the faecal metabolome within and between volunteers as determined by untargeted metabolic profiling by liquid chromatography mass spectrometry (LC-MS) of all faecal samples collected from day 1 to day 9

  3. In vitro metabolic profiling

    Time frame: Day 1-9

    Metabolic profiling of in vitro microbial communities inoculated by faecal outputs from the study

  4. Urine metabolome

    Time frame: Day 1-9

    Changes in the urine metabolome within and between volunteers as determined by untargeted metabolic profiling by LC-MS of all urine samples collected from day 1 to day 9

  5. Postprandial urine metabolome

    Time frame: Day 2

    Diet- and microbial-derived metabolites from the standardised meal determined by metabolic profiling by LC-MS of postprandial urine samples collected at 30 min, 1 hours, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 6-8 hours, 8-10 hours, 10-24 hours

  6. Food intake markers

    Time frame: Day 2-3 and day 8-9

    Food intake biomarkers determined by metabolic profiling by LC-MS of 24-hour urine collection at day 2-3 and day 8-9.

  7. Blood metabolome

    Time frame: Day 2 and 9

    Changes in the blood metabolome within and between volunteers as determined by untargeted metabolic profiling by LC-MS of fasting blood samples collected at day 2 and day 9

  8. Fasting breath hydrogen and methane

    Time frame: Day 2 and 9

    Measurement of fasting breath hydrogen and methane exhalation at day 2 and day 9

  9. Postprandial breath hydrogen and methane

    Time frame: Day 2

    Measurement of fasting and postprandial breath hydrogen and methane exhalation after standardized breakfast (every 30 min until 6 hours post-meal)

  10. Plasma levels of short chain fatty acids

    Time frame: Day 2 and day 9

    Measurement of fasting plasma short-chain fatty acids determined by LC-MS from day 2 and day 9

  11. Faecal levels of short chain fatty acids

    Time frame: Day 1-9

    Measurements of short-chain fatty acids in all faecal samples collected from day 1 to day 9 determined by LC-MS

  12. Intestinal transit time

    Time frame: Day 2-7

    • Whole transit time variation within and between volunteers as determined by the "sweet-corn test". Briefly, participants are instructed to consume sweet corns twice, on day 3 and 5, and to record the times until visible corn excretion on these two occasions, as well as their defecation frequency, and stool consistency during days 1 to 9
    • Whole transit time variation within and between volunteers as determined by the SmartPill Wireless Motility Capsule in the subgroup
    • Comparison of the whole intestinal transit time data obtained by the Smartpill Wireless Motility Capsule and results from the sweet-corn test in the subgroup
    • Small bowel transit time determined by the SmartPill Wireless Motility Capsule in the subgroup
    • Colonic transit time determined by the SmartPill Wireless Motility Capsule in the subgroup

  13. Gastric emptying

    Time frame: Day 2

    • Fluid gastric emptying time determined by the presence of paracetamol metabolites in postprandial urine samples
    • Solid gastric emptying time determined by the SmartPill Wireless Motility Capsule in the subgroup

  14. Appetite hormones

    Time frame: Day 2 and 9

    Determination of different appetite hormones in fasting blood samples at day 2 and day 9 to record baseline values

  15. Glucose levels

    Time frame: Day 2 and 9

    Measurements of glucose in fasting blood samples at day 2 and day 9

  16. Insulin levels

    Time frame: Day 2 and day 9

    Measurement of insulin levels in fasting blood samples at day 2 and day 9

  17. C-peptide levels

    Time frame: Day 2 and day 9

    Measurement of C-peptide levels in fasting blood samples at day 2 and day 9

  18. HbA1c levels

    Time frame: Day 2 and day 9

    Measurement of HbA1c levels in fasting blood samples at day 2 and day 9

  19. Immune system markers

    Time frame: Day 2 and 9

    Measurements of fasting plasma cytokines, C-reactive protein (CRP), lipopolysaccharides (LPS), lipopolysaccharide binding protein (LPS-BP) at day 2 and day 9 to record baseline values

  20. Lipid metabolism

    Time frame: Day 1-9

    Determination of bile acids in fasting blood samples at day 2 and day 9 and in all faecal samples from day 1 to day 9 to associate with changes in abiotic factors

  21. 9-days dietary intake

    Time frame: Day 1-9

    Assessment of dietary intake via myfood24 dietary recalls from day 1 to day 9

  22. Faecal nitrogen

    Time frame: Day 1-9

    Assessment of nitrogen in all faecal samples from day 1 to day 9

  23. Faecal residual carbohydrates

    Time frame: Day 1-9

    Assessment of residual carbohydrates in all faecal samples from day 1 to day 9

  24. Faecal energy

    Time frame: Day 1-9

    Assessment of total energy in all faecal samples from day 1 to day 9

  25. Microbial load assessed by qPCR

    Time frame: Day 1-9

    Assessment of microbial load by quantitative PCR in all faecal samples from day 1 to day 9

  26. Microbial load assessed by flow cytometry

    Time frame: Day 1-9

    Assessment of microbial cell counts by flow cytometry in all faecal samples from day 1 to day 9

  27. Faecal pH

    Time frame: Day 1-9

    Measurements of pH in all faecal samples from day 1 to day 9

  28. Faecal redox potential

    Time frame: Day 1-9

    Measurements of redox potential in all faecal samples from day 1 to day 9

  29. Faecal ionic strength

    Time frame: Day 1-9

    Measurements of ionic strength (Na+ and K+) in all faecal samples from day 1 to day 9

  30. Faecal water content

    Time frame: Day 1-9

    Measurements of water content in all faecal samples from day 1 to day 9

  31. Subjective gastrointestinal symptoms

    Time frame: Day 1-9

    Gastrointestinal symptoms reported on a scale from 0 to 10, where 0 means no symptoms and 10 means the worst possible symptoms. The questionnaire includes these symptoms: overall stomach and intestine symptoms, stomachache, flatulence, bloating, constipation, and diarrhea.

  32. Creatinine

    Time frame: Day 2

    Measurements of urinary levels of creatinine from controlled 6-hour urine collection

  33. Intestinal pH

    Time frame: Day 2-7

    pH measurements throughout the gastrointestinal system determined by the SmartPill Wireless Motility Capsule in the subgroup

  34. Intestinal epithelial cell shedding

    Time frame: Day 1-9

    Measurements of host DNA content in all faecal samples from day 1 to day 9

Sponsors and collaborators

Lead sponsor

University of Copenhagen

Other

Collaborators

  • KU Leuven
  • Technical University of Denmark
  • University of Minnesota

Registry information

Official study title

Towards Personalized Dietary Recommendations Based on the Interaction Between Diet, Microbiome and Abiotic Conditions in the Gut

Acronym: PRIMA

Important dates

Study start
2021
Primary completion
2021
Study completion
2021
First posted
Mar 18, 2021
Registry last updated
Dec 6, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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