Diet, HealthyPRIMA-KOSTNCT06022302
Effects of Changing Intestinal Transit Time on Gut Microbial Composition and Metabolism
A study testing Diet + laxative and Diet only in people with Diet, Healthy and Metabolic Disease, run by University of Copenhagen at 1 site in Denmark.
Trial summary
The aim of this study is to investigate how a short versus a long transit time impacts the gut microbiome's response to a high-fiber and a low-fiber diet, respectively. Such insights could help us understand personal responses to diets and be a first step towards personalized dietary recommendations targeting the gut… Read more about this study
- Who is it for?
- Ages 18 to 75 yearsHealthy volunteers can take part
- Conditions the study is for
- Diet, Healthy, Metabolic Disease
- What is being tested?
- Diet + laxative and Diet only
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 22 participants
- Where
- 1 siteDenmark
- Study dates
- 3 Oct 2023to 29 Nov 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 18.5-30.0 kg/m2 BMI
- Self-reported ≤3.5 spontaneous bowel movements per week
- Willing to collect urine and stool samples at home and able to temporarily store them in their own freezer in a provided container.
- Willing to eat the foods provided.
- Owns a smartphone (iOS 11.0 and later or Android 5.0 and up) with access to the internet.
Who cannot join
- Pregnant or lactating women.
- Diagnosis of irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), inflammatory bowel diseases (IBD), Gastrointestinal obstruction, or Ischemic colitis
- Diagnosed constipation according to the ROME IV criteria
- Intake of antibiotics ˂ 1month, or any medication that can affect the outcomes of the study
- Regular use of diarrhea inhibitors or laxatives
- Dysphagia
Show all 11Show fewer
- Any chronic disease that can affect the outcomes of the study or pose a risk when consuming Movicol
- 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, anti-cholinergic agents, narcotic analgetics, nonsteroidal anti-inflammatory drugs, and peroral glucocorticoids)
- Concurrent participation in another trial
- Any condition that makes the project responsible researcher to doubt the feasibility of the volunteer´s participation
Trial locations and contacts
1 site in 1 country.
Denmark1 site
University of Copenhagen, Department of Nutrition, Exercise and Sports
Copenhagen, 1958
About this study
Official title: Effects of Changing Intestinal Transit Time on Gut Microbial Composition and Metabolism During a Dietary Intervention with Low and High Fiber.
The aim of this study is to investigate how a short versus a long transit time impacts the gut microbiome's response to a high-fiber and a low-fiber diet, respectively. Such insights could help us understand personal responses to diets and be a first step towards personalized dietary recommendations targeting the gut microbiome.
Read the detailed description
The study consists of two parallel arms of whole-meal diets, a low-fiber diet, and a high-fiber diet, respectively. Each arm is designed as a cross-over where participants, in random order, are administered a laxative (Movicol) along with the provided diet to shorten their intestinal transit time or simply consume the provided whole-meal diet (control).
The two intervention periods both involve the following:
- One week of run-in where participants consume the provided whole-meal diet.
- One week where participants either consume Movicol with the provided whole-meal diet or simply continue consuming the provided whole-meal diet (control).
Both arms begin with a screening visit and one week where participants consume and record their habitual diets. Subsequently, the first intervention period follows with one visit before and after each of the two weeks (visit 1-3) followed by the second intervention period with one visit before and after each of the two weeks (visit 4-6). The two cross-over periods are split by a washout of at least two weeks.
The study thus runs for approximately 7-8 weeks depending on the length of the washout and consists of seven visits (one screening visit and six regular visits) in total.
- Conditions
- Diet, Healthy, Metabolic Disease
- Being tested
- Diet + laxative, Diet only
- Keywords
- Microbiome, Metabolomics, Transit time, Nutrition, Dietary fibre
- Medical subject headings
- Metabolic Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Diet + laxativeDrug
The participants will start by consuming one sacket of Movicol powder (13 g macrogol 3350) on the first day. On day 2, the participants will consume two sackets of Movicol powder (26 g macrogol 3350), one with breakfast in the morning and one before sleep in the evening. The participants will continue consuming two sackets per day (one morning, one evening) until the following study visit, day 8 (seven days in total). If the participants have a very loose stomach (recorded as Bristol stool scale ≥6), they will be instructed to reduce Movicol by one sacket/day. In case the participants have not passed a stool on day 2 or in the morning of day 3, the participants will increase the dose to a maximum of three sackets of Movicol powder (39 g macrogol 3350) per day (morning, noon, and evening) and continue this until the following study visit at day 8. If three sackets cause very loose stomach the participants will decrease the number of sackets consumed.
Diet onlyOther
Also called Control
This is only a control and participants will not receive Movicol.
| Study group | Role | What they receive |
|---|---|---|
| High-fiber diet | Experimental | The high-fiber diet will consist of foods rich in dietary fiber such as coarse vegetables, wholegrain bread, and fruits representing a broad range of dietary fibers aiming for ≈40 g of fiber/10 MJ. Receives: Drug: Diet + laxative; Other: Diet only |
| Low-fiber diet | Experimental | The low-fiber diet will consist of foods poor in fiber such as white bread and refined foods aiming for ≈10 g of fiber/10 MJ. Receives: Drug: Diet + laxative; Other: Diet only |
What is being measured
The primary outcome is the main question the study is designed to answer.
Fecal butyrate over urine p-cresol sulfate ratio
Changes in ratio between fecal butyrate (reflecting saccharolytic fermentation) and urine p-cresol sulfate (reflecting proteolytic fermentation) between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Secondary outcomes (16)
Whole gut transit time measured by sweet corn
Changes in whole gut transit time between interventions determined by the passage time of sweet corn.
Measured: From visit 1 through to study completion, an average of 7 weeks
Whole gut transit time measured by blue muffins
Changes in whole gut transit time between interventions determined by the passage time of muffins with blue dye.
Measured: From visit 1 through to study completion, an average of 7 weeks
Stool consistency
Changes in stool consistency determined by Bristol Stool Scale. The Bristol Stool Scale measures stool consistency on a scale from 1-7 with high numbers reflecting loose stool.
Measured: From visit 1 through to study completion, an average of 7 weeks
Change in bowel movement frequency
Changes in bowel movement frequency will be measured by the participants recording every bowel movement in a defecation diary during the study.
Measured: From visit 1 through to study completion, an average of 7 weeks
Fecal water content in percentage of stool weight
Change in fecal water content between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Fecal concentration of short-chain fatty acids
Change in concentration of short-chain fatty acids between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Fecal pH
Change in fecal pH level between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Fecal ammonia concentration
Change in ammonia content between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Concentration of fasting plasma short-chain fatty acids
Change in concentration of short-chain fatty acids between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Fasting plasma concentrations of bile acids
Change in concentration of bile acids in fasting blood between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Fasting breath methane and hydrogen levels in parts per million
Changes in fasting breath methane and hydrogen concentration measured in parts per million (PPM) in exhalations between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Microbial metabolites in urine from proteolytic fermentation as assessed by mass spectrometry
Changes in the urine concentration of metabolites of microbial proteolysis between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Microbial metabolites in blood from proteolytic fermentation as assessed by mass spectrometry
Changes in the blood concentration of metabolites of microbial proteolysis between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Fecal metabolome as assessed by untargeted metabolomics
Changes in the fecal metabolome between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Gut microbiome assessed by shotgun sequencing
Changes in gut microbiota composition between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Gut microbiome assessed by 16S amplicon sequencing
Changes in gut microbiota composition between interventions.
Measured: From visit 1 through to study completion, an average of 7 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Sep 2023
- Study start3 Oct 2023
- Primary completion29 Nov 2024
- Study completion29 Nov 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Diet, HealthyStudies of the same condition, open and under way.
- More trials run by University of CopenhagenThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Overall, there are two parallel arms (low- and high-fiber diet) to which the participants will be randomized with an allocation ratio 1:1. In each arm participants will be exposed to a crossover design where participants in random order will continue on the meal intervention alone (control) or receive Movicol (a laxative) along with the meal intervention to shorten intestinal transit time.
- Masking
- None (open label)
- Enrolment
- 22 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Copenhagen
- Sponsor type
- University, hospital or other
- Collaborators
- Technical University of Denmark, KU Leuven, University of Minnesota
- Responsible party
- Principal investigator, Henrik Munch Roager, University of Copenhagen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06022302
- Sponsor's protocol ID
- M245
- Acronym
- PRIMA-KOST
- Status last verified
- Mar 2025
- First submitted
- 11 Aug 2023
- Last updated
- 19 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 19 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Changing Intestinal Transit Time on Gut Microbial Composition and Metabolism During a Dietary Intervention with Low and High Fiber.
- ClinicalTrials.gov ID
- NCT06022302
- Acronym / sponsor ID
- PRIMA-KOST / M245
- Conditions
- Diet, Healthy, Metabolic Disease
- Keywords
- Microbiome, Metabolomics, Transit time, Nutrition, Dietary fibre
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 22 participants (actual)
- Lead sponsor
- University of CopenhagenUniversity, hospital or other
- Collaborators
- Technical University of Denmark, KU Leuven, University of Minnesota
- Study start
- 3 Oct 2023 (actual)
- Primary completion
- 29 Nov 2024 (actual)
- Study completion
- 29 Nov 2024 (actual)
- First posted
- 1 Sep 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this study is to investigate how a short versus a long transit time impacts the gut microbiome's response to a high-fiber and a low-fiber diet, respectively. Such insights could help us understand personal responses to diets and be a first step towards personalized dietary recommendations targeting the gut microbiome.
Detailed description
The study consists of two parallel arms of whole-meal diets, a low-fiber diet, and a high-fiber diet, respectively. Each arm is designed as a cross-over where participants, in random order, are administered a laxative (Movicol) along with the provided diet to shorten their intestinal transit time or simply consume the provided whole-meal diet (control).
The two intervention periods both involve the following:
- One week of run-in where participants consume the provided whole-meal diet.
- One week where participants either consume Movicol with the provided whole-meal diet or simply continue consuming the provided whole-meal diet (control).
Both arms begin with a screening visit and one week where participants consume and record their habitual diets. Subsequently, the first intervention period follows with one visit before and after each of the two weeks (visit 1-3) followed by the second intervention period with one visit before and after each of the two weeks (visit 4-6). The two cross-over periods are split by a washout of at least two weeks.
The study thus runs for approximately 7-8 weeks depending on the length of the washout and consists of seven visits (one screening visit and six regular visits) in total.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Overall, there are two parallel arms (low- and high-fiber diet) to which the participants will be randomized with an allocation ratio 1:1. In each arm participants will be exposed to a crossover design where participants in random order will continue on the meal intervention alone (control) or receive Movicol (a laxative) along with the meal intervention to shorten intestinal transit time.
| Arm | Type | Receives |
|---|---|---|
| High-fiber diet | Experimental | Drug: Diet + laxative, Other: Diet onlyThe high-fiber diet will consist of foods rich in dietary fiber such as coarse vegetables, wholegrain bread, and fruits representing a broad range of dietary fibers aiming for ≈40 g of fiber/10 MJ. |
| Low-fiber diet | Experimental | Drug: Diet + laxative, Other: Diet onlyThe low-fiber diet will consist of foods poor in fiber such as white bread and refined foods aiming for ≈10 g of fiber/10 MJ. |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- 18.5-30.0 kg/m2 BMI
- Self-reported ≤3.5 spontaneous bowel movements per week
- Willing to collect urine and stool samples at home and able to temporarily store them in their own freezer in a provided container.
- Willing to eat the foods provided.
- Owns a smartphone (iOS 11.0 and later or Android 5.0 and up) with access to the internet.
Key exclusion criteria (11 listed)
- Pregnant or lactating women.
- Diagnosis of irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), inflammatory bowel diseases (IBD), Gastrointestinal obstruction, or Ischemic colitis
- Diagnosed constipation according to the ROME IV criteria
- Intake of antibiotics ˂ 1month, or any medication that can affect the outcomes of the study
- Regular use of diarrhea inhibitors or laxatives
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Diet + laxativeThe participants will start by consuming one sacket of Movicol powder (13 g macrogol 3350) on the first day. On day 2, the participants will consume two sackets of Movicol powder (26 g macrogol 3350), one with breakfast in the morning and one before sleep in the evening. The participants will continue consuming two sackets per day (one morning, one evening) until the following study visit, day 8 (seven days in total). If the participants have a very loose stomach (recorded as Bristol stool scale ≥6), they will be instructed to reduce Movicol by one sacket/day. In case the participants have not passed a stool on day 2 or in the morning of day 3, the participants will increase the dose to a maximum of three sackets of Movicol powder (39 g macrogol 3350) per day (morning, noon, and evening) and continue this until the following study visit at day 8. If three sackets cause very loose stomach the participants will decrease the number of sackets consumed. | Drug | High-fiber diet, Low-fiber diet |
| Diet onlyAlso: ControlThis is only a control and participants will not receive Movicol. | Other | High-fiber diet, Low-fiber diet |
Primary outcome
Fecal butyrate over urine p-cresol sulfate ratio
Time frame: From visit 1 through to study completion, an average of 7 weeks
Changes in ratio between fecal butyrate (reflecting saccharolytic fermentation) and urine p-cresol sulfate (reflecting proteolytic fermentation) between interventions.
16 secondary outcomes
Whole gut transit time measured by sweet corn
Time frame: From visit 1 through to study completion, an average of 7 weeks
Whole gut transit time measured by blue muffins
Time frame: From visit 1 through to study completion, an average of 7 weeks
Stool consistency
Time frame: From visit 1 through to study completion, an average of 7 weeks
Change in bowel movement frequency
Time frame: From visit 1 through to study completion, an average of 7 weeks
Fecal water content in percentage of stool weight
Time frame: From visit 1 through to study completion, an average of 7 weeks
Fecal concentration of short-chain fatty acids
Time frame: From visit 1 through to study completion, an average of 7 weeks
Fecal pH
Time frame: From visit 1 through to study completion, an average of 7 weeks
Fecal ammonia concentration
Time frame: From visit 1 through to study completion, an average of 7 weeks
Concentration of fasting plasma short-chain fatty acids
Time frame: From visit 1 through to study completion, an average of 7 weeks
Fasting plasma concentrations of bile acids
Time frame: From visit 1 through to study completion, an average of 7 weeks
Fasting breath methane and hydrogen levels in parts per million
Time frame: From visit 1 through to study completion, an average of 7 weeks
Microbial metabolites in urine from proteolytic fermentation as assessed by mass spectrometry
Time frame: From visit 1 through to study completion, an average of 7 weeks
Microbial metabolites in blood from proteolytic fermentation as assessed by mass spectrometry
Time frame: From visit 1 through to study completion, an average of 7 weeks
Fecal metabolome as assessed by untargeted metabolomics
Time frame: From visit 1 through to study completion, an average of 7 weeks
Gut microbiome assessed by shotgun sequencing
Time frame: From visit 1 through to study completion, an average of 7 weeks
Gut microbiome assessed by 16S amplicon sequencing
Time frame: From visit 1 through to study completion, an average of 7 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 Mar 2025.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Diet + laxative and Diet only in people with Diet, Healthy and Metabolic Disease, run by University of Copenhagen at 1 site in Denmark.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 19 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Denmark. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Fecal butyrate over urine p-cresol sulfate ratio (time frame: From visit 1 through to study completion, an average of 7 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Mar 2025.