NCT07587424

Brief Summary

Fibres found in food are mainly carbohydrates that are not broken down or absorbed during human digestion but instead pass to the colon to be fermented by microbes. Gases produced during bacterial fermentation (hydrogen, methane, and carbon dioxide), can cause unpleasant gastrointestinal symptoms in some individuals, such as bloating, flatulence, and stomach pain. Gas production varies between individuals and is influenced by the chemical structure of dietary fibres, the gut microbes' ability to ferment fibre, intestinal pH, and the transit time of intestinal contents. This randomized clinical trial in healthy adults will investigate how individual variations in the microbiome influence the level of gastrointestinal (GI) symptoms induced by different fibre types during short-term exposure.

Trial Health

63
Monitor

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
28

participants targeted

Target at below P25 for not_applicable

Timeline
1mo left

Started Aug 2026

Shorter than P25 for not_applicable

Geographic Reach
1 country

1 active site

Status
not yet recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

May 7, 2026

Completed
7 days until next milestone

First Posted

Study publicly available on registry

May 14, 2026

Completed
3 months until next milestone

Study Start

First participant enrolled

August 17, 2026

Expected
1 month until next milestone

Primary Completion

Last participant's last visit for primary outcome

September 30, 2026

Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

September 30, 2026

Last Updated

May 14, 2026

Status Verified

May 1, 2026

Enrollment Period

1 month

First QC Date

May 7, 2026

Last Update Submit

May 7, 2026

Conditions

Gastrointestinal Symptoms

Keywords

dietary fibredietary fibergut symptomsmicrobiotamicrobiomegastrointestinal discomfort

Outcome Measures

Primary Outcomes (10)

  • Intensity of gastrointestinal symptoms, total score

    The composite score of the intensity of individual gastrointestinal symptoms reported on a VAS scale by the participants.

    6 weeks Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Intensity of stomach/ abdominal pain

    Intensity of experienced stomach/ abdominal pain reported on a VAS scale from zero (no pain) to 100 (very intense pain) by the participants on daily basis.

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Intensity of bloating

    Intensity of experienced bloatingreported on a VAS scale from zero (no symptoms) to 100 (very intense symptoms) by the participants on daily basis.

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Intensity of stomach cramps

    Intensity of experienced stomach cramps reported on a VAS scale from zero (no pain) to 100 (very intense pain) by the participants on daily basis.

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared

  • Intensity of flatulence

    Intensity of experienced flatulence reported on a VAS scale from zero (no symptoms) to 100 (very intense symptoms) by the participants on daily basis.

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Intensity of borborygmus

    Intensity of experienced borborygmus reported on a VAS scale from 0 (no symptoms) to 100 (very intense symptoms) by the participants on daily basis

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Intensity of nausea

    Intensity of experienced nausea reported on a VAS scale from 0 (no symptoms) to 100 (very intense symptoms) by the participants on daily basis.

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Intensity of heartburn

    Intensity of experienced heartburn reported on a VAS scale from 0 (no symptoms) to 100 (very intense symptoms) by the participants on daily basis.

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Intensity of discomfort in the upper abdomen or unpleasant sensation of fullness following eating

    Intensity of experienced discomfort or unpleasant sensation reported on a VAS scale from 0 (no symptoms) to 100 (very intense symptoms) by the participants on daily basis.

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Intensity of a sudden need to defecate

    Intensity of experienced discomfort or unpleasant sensation reported on a VAS scale from 0 (no symptoms) to 100 (very intense symptoms) by the participants on daily basis.

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

Secondary Outcomes (4)

  • Composition and function of gut microbiome

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Number of bowel movements

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Breath gases

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Fecal and blood SCFA

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

Other Outcomes (3)

  • Dietary intake

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Physical activity

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

  • Metabolomics from feces, blood and urine

    6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.

Study Arms (3)

Cellulose

EXPERIMENTAL

poorly fermentable fibre, "negative control"

Dietary Supplement: cellulose

Oat fibre

EXPERIMENTAL

fibre-rich product from oat bran

Dietary Supplement: Oat fibre

Rye fibre

EXPERIMENTAL

fibre-rich product from rye bran

Dietary Supplement: Rye fibre

Interventions

celluloseDIETARY_SUPPLEMENT

Microcrystalline cellulose; daily dose of fibre from the study product 20 g for females and 25 g for males on 4 consecutive days

Cellulose
Oat fibreDIETARY_SUPPLEMENT

Oat bran-based fibre product; daily dose of fibre from the study product 20 g for females and 25 g for males on 4 consecutive days

Oat fibre
Rye fibreDIETARY_SUPPLEMENT

Rye bran-based fibre product; daily dose of fibre from the study product 20 g for females and 25 g for males on 4 consecutive days

Rye fibre

Eligibility Criteria

Age18 Years - 65 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • healthy male and female
  • aged 18-65 years
  • experience gastrointestinal discomfort during or after eating
  • willing to commit to the 6-week study period and follow the study schedule.

You may not qualify if:

  • Body mass index ≤ 18.5 or ≥ 35 kg/m².
  • Inflammatory bowel diseases, irritable bowel syndrome (IBS), celiac disease, endocrine or lipid metabolism disorders, liver or kidney diseases, cancer within the past 5 years, eating disorders.
  • Medication for gastrointestinal symptoms, bowel function, diabetes, or hypercholesterolemia.
  • Regular or recent use of antibiotics (within the last 3 months).
  • Food allergies to the ingredients of the study products.
  • Heavy, long-duration exercise several times a week.
  • Smoking, use of snus or nicotine pouches.
  • Planned or ongoing pregnancy or breastfeeding.
  • In addition, the site-specific principal investigator may exclude a person due to any illness, medication, or factor they deem relevant for the participant's health and safety or for the conduct of the study.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Department of Food and Nutrition, University of Helsinki

Helsinki, Uusimaa, Finland

Location

MeSH Terms

Interventions

Cellulose

Intervention Hierarchy (Ancestors)

GlucansBiopolymersPolymersMacromolecular SubstancesPolysaccharidesCarbohydratesBiomedical and Dental MaterialsManufactured MaterialsTechnology, Industry, and Agriculture

Central Study Contacts

Anne-Maria Pajari, Professor

CONTACT

+358294158203anne-maria.pajari@helsinki.fi

Maija Marttinen, PhD

CONTACT

+358294158209maija.marttinen@helsinki.fi

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
TRIPLE
Who Masked
PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
Purpose
PREVENTION
Intervention Model
CROSSOVER
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Professor

Study Record Dates

First Submitted

May 7, 2026

First Posted

May 14, 2026

Study Start (Estimated)

August 17, 2026

Primary Completion (Estimated)

September 30, 2026

Study Completion (Estimated)

September 30, 2026

Last Updated

May 14, 2026

Record last verified: 2026-05

Data Sharing

IPD Sharing
Will not share

Data sharing in agreement with the EU General Data Protection Regulation

Locations

FI(1)