OHSU Knight Cancer Institute
Portland, Oregon, 97239, United States
Location status: Recruiting
Location contact
Vassiliki L. Tsikitis, M.D.
CONTACT
Vassiliki L. Tsikitis, M.D.
PRINCIPAL_INVESTIGATOR
Recruiting
NCT Number: NCT05643859
Impact of Dietary Fiber Supplementation on Colonic Microbiome
This clinical trial tests whether daily fiber supplementation will change the mucosal microbiome of the colon. The microbiome are microorganisms that live in the human gut. They serve a vital role in maintaining health. Certain microbial strains are associated with the growth of colon polyps, which eventually could go on to form colon cancer. Giving dietary fiber supplements may help prevent precancerous polyps from ever developing.
Recruiting
Interested in participating?
Request InfoKey information
Age range
18 year and older
Sex eligibility
All sexes
Study type
Interventional
Phase
Not applicable
Primary location
About this study
PRIMARY OBJECTIVE:
I. To identify how diet, specifically fiber supplementation, alters the microbiome of the colonic mucosa.
OUTLINE:
Patients receive dietary fiber orally (PO) once daily (QD) for 28 days. Patients may undergo standard of care proctoscopy or anoscopy with biopsy on study and at follow up or may undergo standard of care colonoscopy on study. All patients also undergo collection of blood samples on study and at follow up.
Who can participate
Healthy volunteers accepted: No
Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
- Age >= 18 years
- Ability to understand and the willingness to sign a written informed consent document
- Patients who present with a chief complaint of a benign anorectal pathology including hemorrhoids, anal fissures, and anal fistulas without underlying conditions such as colorectal cancer or Crohn's disease or are undergoing a standard of care colonoscopy procedure
Exclusion criteria
- Patients with an active malignancy, Crohn's disease, ulcerative colitis, and immunosuppressed patients
- Patients with hereditary colon cancer syndrome including Lynch syndrome or Familial Adenomatous Polyposis (FAP)
- Patients with a prior history of total or partial colon resection
- Colorectal pathology, such cancer or proctitis, after initial study scope
Treatment and study plan
Dietary fiber
Dietary SupplementGiven PO
Other names: Fiber
Proctoscopy or anoscopy with Biopsy
ProcedureUndergo proctoscopy or anoscopy
colonoscopy
ProcedureUndergo Colonoscopy
Questionnaire Administration
OtherAncillary studies
Primary outcomes
-
Change in microbiome colonic mucosa: taxa abundance
Time frame: Baseline and post-supplementation, up to 40 days
Will use data visualization techniques to understand the data and determine if microbiome count overall (richness) changes occur in patients who are started on fiber supplementation. In order to visualize overall changes after fiber supplementation, will generate plots showing relative abundance of the detected taxa for each subject at baseline and post-supplementation. For each taxa, will generate box plots to visually compare the median and interquartile range (IQR) of abundance between the two time points. Wilcoxon signed rank tests with an alpha level of 0.05 will determine if there is a difference in microbial derived short chain fatty acids after fiber supplementation in the blood and mucosa. Wilcoxon signed rank tests with an alpha level of 0.05 will determine if there is a difference in microbial derived short chain fatty acids after fiber supplementation in the blood and mucosa.
-
Change in microbiome colonic mucosa: microbiome diversity
Time frame: Baseline and post-supplementation, up to 40 days
Will use data visualization techniques to understand the data and determine if the types of metabolites (microbiome diversity) cases occur in patients who are started on fiber supplementation. In order to visualize overall changes after fiber supplementation. To assess for changes in microbiome diversity, our primary analysis will compare median Shannon diversity index values at baseline and post-supplementation. The Shannon index estimates diversity using richness and abundance. Will calculate Shannon index values for each participant at each time point and use a Wilcoxon signed rank test with an alpha level of 0.05 to determine if there is a difference in microbiome diversity after fiber supplementation.
Study contacts
Contact information is provided by the study sponsor or research team.
Amber O'Connor
CONTACT
Shahrose Rahman, M.D.
CONTACT
Sponsors and collaborators
Lead sponsor
OHSU Knight Cancer Institute
Other
Registry information
Official study title
Changes in Colonic Microbiome With Fiber Supplementation
Important dates
- Study start
- 2023
- Primary completion
- 2026
- Study completion
- 2026
- First posted
- Dec 9, 2022
- Registry last updated
- Jan 15, 2026
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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