Gastrointestinal SymptomsKiVaNCT07587424
Impact of Dietary Fibre Supplementation on Gut Symptoms in Healthy Participants
A study testing cellulose, Oat fibre and Rye fibre in people with Gastrointestinal Symptoms, run by University of Helsinki at 1 site in Finland.
Trial 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… Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Gastrointestinal Symptoms
- What is being tested?
- cellulose, Oat fibre and Rye fibre
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 28 participants
- Where
- 1 siteFinland
- Study dates
- 17 Aug 2026to 30 Sep 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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.
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- 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.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Finland1 site
Department of Food and Nutrition, University of Helsinki
Helsinki, Uusimaa
Anne-Maria Pajari, Professor, +358294158203, anne-maria.pajari@helsinki.fi
Maija Marttinen, PhD, +358294158209, maija.marttinen@helsinki.fi
About this study
Official title: The Effect of Dietary Fibre Supplementation on Gastrointestinal Symptoms in Healthy Participants - KiVa-trial
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.
Read the detailed description
The objective of this dietary intervention is to examine the effects of different dietary fibre types on gastrointestinal symptoms in apparently healthy adults and to investigate how these effects relate to the composition and functional capacity of the gut microbiota.
The study is designed as a randomized, crossover intervention trial with a total duration of approximately 6 weeks. A 5-day run-in phase is carried out to stabilize baseline dietary patterns and ensure adherence to study procedures. During the intervention, each participant consumes 3 different fibre-rich products, with each product administered for 4 consecutive days (referred to as a "fibre period"). Each fibre period is separated by a 10-day washout period.
Participants (n=28) are apparently healthy adult males and females aged 18-65 years who experience gastrointestinal/ digestive discomfort during or after eating. Individuals without such symptoms are unlikely to exhibit measurable responses, which would limit the ability to address the study's primary research questions.
During the 4-day fibre period, the daily fibre dose provided by the study product is 20 g for women and 25 g for men (corresponding to 2.5 g of fibre per MJ of energy intake, assuming daily energy intake of 8 MJ for women and 10 MJ for men). During the trial, participants consume three structurally different types of dietary fibre: cellulose (poorly fermentable fibre; microcrystalline cellulose), beta-glucan rich fibre (oat bran-based fibre product), and arabinoxylan rich fibre (rye bran-based fibre product). Participants are randomly assigned into one of the six predefined intervention sequences, which represent all possible orders of exposure to the 3 fibre products. Sequence allocation will be generated prior to enrolment, and participants will receive each fibre-rich test product in a randomized order. Participants are instructed to keep the rest of their diet as habitual as possible during the study. Regular use of dietary supplements must be discontinued for the study duration
Participants report their daily GI symptoms as well as perceived stress and mood through a symptom questionnaire using a mobile app. A total of nine GI symptoms are reported (i.e., stomach/ abdominal pain, stomach cramps, bloating, flatulence, borborygmus, nausea, heartburn, discomfort in the upper abdomen/ unpleasant sensation of fullness following eating, a sudden need to defecate), and their severity of symptoms is assessed on a 0-100 VAS scale. Participants report daily the number of bowel movements through the online form, as well as their daily amount of physical activity. In addition, physical activity is assessed using an accelerometer. Dietary intake is assessed by food records (3-day food records during the run-in period and 2-day food records during each fibre period).
Stool samples are used for the analysis of the gut microbiota and metabolome. Additionally, the the effects of different fibre types on metabolic profiles in blood, urine, and stool samples (including SCFAs), as well as on gases in exhaled breath will be analysed.
- Conditions
- Gastrointestinal Symptoms
- Being tested
- cellulose, Oat fibre, Rye fibre
- Keywords
- dietary fibre, dietary fiber, gut symptoms, microbiota, microbiome, gastrointestinal discomfort
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
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
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
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
| Study group | Role | What they receive |
|---|---|---|
| Cellulose | Experimental | poorly fermentable fibre, "negative control" Receives: Dietary Supplement: cellulose |
| Oat fibre | Experimental | fibre-rich product from oat bran Receives: Dietary Supplement: Oat fibre |
| Rye fibre | Experimental | fibre-rich product from rye bran Receives: Dietary Supplement: Rye fibre |
What is being measured
The primary outcome is the main question the study is designed to answer.
Intensity of gastrointestinal symptoms, total score
The composite score of the intensity of individual gastrointestinal symptoms reported on a VAS scale by the participants.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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
Microbiota-related analyses of the collected stool samples are carried out using DNA-based methods
Measured: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Number of bowel movements
Number of bowel movements reported by participants on daily basis using a mobile app.
Measured: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Breath gases
Hydrogen and methane measured from exhaled breath samples during run-in and fibre periods.
Measured: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Fecal and blood SCFA
Analysis of short chain fatty acids (SCFA) from stool and blood samples
Measured: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 May 2026
- Study start17 Aug 2026 (estimated)
- Primary completion30 Sep 2026 (estimated)
- Study completion30 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Gastrointestinal SymptomsStudies of the same condition, open and under way.
- 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 28 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Helsinki
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Anne-Maria Pajari, University of Helsinki
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07587424
- Sponsor's protocol ID
- FIBRE-MATCH Helsinki Pilot
- Other IDs
- 101161484
- Acronym
- KiVa
- Status last verified
- May 2026
- First submitted
- 7 May 2026
- Last updated
- 14 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Data sharing in agreement with the EU General Data Protection Regulation
Study at a glance
From the registry record, last updated by the sponsor on 14 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Dietary Fibre Supplementation on Gastrointestinal Symptoms in Healthy Participants - KiVa-trial
- ClinicalTrials.gov ID
- NCT07587424
- Acronym / sponsor ID
- KiVa / FIBRE-MATCH Helsinki Pilot
- Conditions
- Gastrointestinal Symptoms
- Keywords
- dietary fibre, dietary fiber, gut symptoms, microbiota, microbiome, gastrointestinal discomfort
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 28 participants (estimated)
- Lead sponsor
- University of HelsinkiUniversity, hospital or other
- Study start
- 17 Aug 2026 (estimated)
- Primary completion
- 30 Sep 2026 (estimated)
- Study completion
- 30 Sep 2026 (estimated)
- First posted
- 14 May 2026 (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.
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.
Detailed description
The objective of this dietary intervention is to examine the effects of different dietary fibre types on gastrointestinal symptoms in apparently healthy adults and to investigate how these effects relate to the composition and functional capacity of the gut microbiota.
The study is designed as a randomized, crossover intervention trial with a total duration of approximately 6 weeks. A 5-day run-in phase is carried out to stabilize baseline dietary patterns and ensure adherence to study procedures. During the intervention, each participant consumes 3 different fibre-rich products, with each product administered for 4 consecutive days (referred to as a "fibre period"). Each fibre period is separated by a 10-day washout period.
Participants (n=28) are apparently healthy adult males and females aged 18-65 years who experience gastrointestinal/ digestive discomfort during or after eating. Individuals without such symptoms are unlikely to exhibit measurable responses, which would limit the ability to address the study's primary research questions.
During the 4-day fibre period, the daily fibre dose provided by the study product is 20 g for women and 25 g for men (corresponding to 2.5 g of fibre per MJ of energy intake, assuming daily energy intake of 8 MJ for women and 10 MJ for men). During the trial, participants consume three structurally different types of dietary fibre: cellulose (poorly fermentable fibre; microcrystalline cellulose), beta-glucan rich fibre (oat bran-based fibre product), and arabinoxylan rich fibre (rye bran-based fibre product). Participants are randomly assigned into one of the six predefined intervention sequences, which represent all possible orders of exposure to the 3 fibre products. Sequence allocation will be generated prior to enrolment, and participants will receive each fibre-rich test product in a randomized order. Participants are instructed to keep the rest of their diet as habitual as possible during the study. Regular use of dietary supplements must be discontinued for the study duration
Participants report their daily GI symptoms as well as perceived stress and mood through a symptom questionnaire using a mobile app. A total of nine GI symptoms are reported (i.e., stomach/ abdominal pain, stomach cramps, bloating, flatulence, borborygmus, nausea, heartburn, discomfort in the upper abdomen/ unpleasant sensation of fullness following eating, a sudden need to defecate), and their severity of symptoms is assessed on a 0-100 VAS scale. Participants report daily the number of bowel movements through the online form, as well as their daily amount of physical activity. In addition, physical activity is assessed using an accelerometer. Dietary intake is assessed by food records (3-day food records during the run-in period and 2-day food records during each fibre period).
Stool samples are used for the analysis of the gut microbiota and metabolome. Additionally, the the effects of different fibre types on metabolic profiles in blood, urine, and stool samples (including SCFAs), as well as on gases in exhaled breath will be analysed.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Cellulose | Experimental | Dietary Supplement: cellulosepoorly fermentable fibre, "negative control" |
| Oat fibre | Experimental | Dietary Supplement: Oat fibrefibre-rich product from oat bran |
| Rye fibre | Experimental | Dietary Supplement: Rye fibrefibre-rich product from rye bran |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- 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.
Key exclusion criteria (9 listed)
- 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.
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 |
|---|---|---|
| celluloseMicrocrystalline cellulose; daily dose of fibre from the study product 20 g for females and 25 g for males on 4 consecutive days | Dietary supplement | Cellulose |
| Oat fibreOat 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 | Dietary supplement | Oat fibre |
| Rye fibreRye 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 | Dietary supplement | Rye fibre |
Primary outcome
Intensity of gastrointestinal symptoms, total score
Time frame: 6 weeks Differences between the fibre periods and fibre periods and run-in period will be compared.
The composite score of the intensity of individual gastrointestinal symptoms reported on a VAS scale by the participants.
Intensity of stomach/ abdominal pain
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
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.
Intensity of bloating
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Intensity of experienced bloatingreported on a VAS scale from zero (no symptoms) to 100 (very intense symptoms) by the participants on daily basis.
Intensity of stomach cramps
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared
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.
Intensity of flatulence
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Intensity of experienced flatulence reported on a VAS scale from zero (no symptoms) to 100 (very intense symptoms) by the participants on daily basis.
Intensity of borborygmus
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Intensity of experienced borborygmus reported on a VAS scale from 0 (no symptoms) to 100 (very intense symptoms) by the participants on daily basis
Intensity of nausea
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Intensity of experienced nausea reported on a VAS scale from 0 (no symptoms) to 100 (very intense symptoms) by the participants on daily basis.
Intensity of heartburn
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Intensity of experienced heartburn reported on a VAS scale from 0 (no symptoms) to 100 (very intense symptoms) by the participants on daily basis.
Intensity of discomfort in the upper abdomen or unpleasant sensation of fullness following eating
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
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.
Intensity of a sudden need to defecate
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
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.
4 secondary outcomes
Composition and function of gut microbiome
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Number of bowel movements
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Breath gases
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Fecal and blood SCFA
Time frame: 6 weeks. Differences between the fibre periods and fibre periods and run-in period will be compared.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 May 2026.
- Individual participant dataSharing planned: No. Data sharing in agreement with the EU General Data Protection Regulation
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing cellulose, Oat fibre and Rye fibre in people with Gastrointestinal Symptoms, run by University of Helsinki at 1 site in Finland.
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 4 inclusion and 9 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: opening soon, as of the sponsor's last update on 14 May 2026. 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 Finland. 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Anne-Maria Pajari, Professor (+358294158203, anne-maria.pajari@helsinki.fi), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Intensity of gastrointestinal symptoms, total score (time frame: 6 weeks Differences between the fibre periods and fibre periods and run-in period will be compared.). The study lists 10 primary outcomes in all. 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 14 May 2026.