Effects of Changing Intestinal Transit Time on Gut Microbial Composition and Metabolism

NCT06022302 | Completed

• 1 other identifier: M245
• Study Type: interventional
• Target: 22
• Locations: 1 country
• Sites: 1

Brief 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 microbiome.

Conditions

Diet, Healthy; Metabolic Disease

Keywords

Microbiome; Metabolomics; Transit time; Nutrition; Dietary fibre

Outcome Measures

Primary Outcomes (1)

• 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.

  From visit 1 through to study completion, an average of 7 weeks

Secondary Outcomes (16)

• Whole gut transit time measured by sweet corn

  From visit 1 through to study completion, an average of 7 weeks

• Whole gut transit time measured by blue muffins

  From visit 1 through to study completion, an average of 7 weeks

• Stool consistency

  From visit 1 through to study completion, an average of 7 weeks

• Change in bowel movement frequency

  From visit 1 through to study completion, an average of 7 weeks

• Fecal water content in percentage of stool weight

  From visit 1 through to study completion, an average of 7 weeks

Other Outcomes (23)

• Urine metabolome as assessed by untargeted metabolomics

  From visit 1 through to study completion, an average of 7 weeks

• Blood metabolome as assessed by untargeted metabolomics

  From visit 1 through to study completion, an average of 7 weeks

• Fecal microbial metabolites of proteolytic fermentation measured by mass spectrometry

  From visit 1 through to study completion, an average of 7 weeks

Study Arms (2)

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.

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.

Drug: Diet + laxative; Other: Diet only

Interventions

Diet + laxative DRUG

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.

High-fiber diet; Low-fiber diet

Diet only OTHER

This is only a control and participants will not receive Movicol.

Also known as: Control

High-fiber diet; Low-fiber diet

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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
• 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

Sponsors & Collaborators

• University of Copenhagen: lead
• Technical University of Denmark: collaborator
• KU Leuven: collaborator
• University of Minnesota: collaborator

Study Sites (1)

University of Copenhagen, Department of Nutrition, Exercise and Sports

Copenhagen, 1958, Denmark

Location

MeSH Terms

Conditions

Metabolic Diseases

Interventions

Diet; Laxatives

Condition Hierarchy (Ancestors)

Nutritional and Metabolic Diseases

Intervention Hierarchy (Ancestors)

Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena; Gastrointestinal Agents; Therapeutic Uses; Pharmacologic Actions; Chemical Actions and Uses

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Model Details: 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.

Study Record Dates

• First Submitted: August 11, 2023
• First Posted: September 1, 2023
• Study Start: October 3, 2023
• Primary Completion: November 29, 2024
• Study Completion: November 29, 2024
• Last Updated: March 19, 2025

Record last verified: 2025-03

Locations

DK (1)