Healthy AdultsFIBRE-MATCHNCT07594600
The Effect of Low or High Dietary Fiber Diet on Volatile Organic Compounds in Exhaled Breath of Healthy Individuals
A study testing Low, High Fiber Diet and High, Low Fiber Diet in people with Healthy Adults and Dietary Fiber Fermentation, run by Örebro University, Sweden at 1 site in Sweden.
Trial summary
The aim of this crossover intervention study is to evaluate the volatile organic compounds (VOCs) present in participants at baseline and how these levels change after consuming either a low- or high-dietary fiber diet for three days. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Adults, Dietary Fiber Fermentation
- What is being tested?
- Low, High Fiber Diet and High, Low Fiber Diet
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteSweden
- Study dates
- 25 May 2026to Mar 2027
- 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
- Signed informed consent obtained prior to any study-related procedures.
- Willingness to refrain from regular consumption of prebiotic or probiotic products, as well as medications known to affect gastrointestinal function, for at least four weeks prior to the study visits.
Who cannot join
- History of complicated gastrointestinal surgery.
- Presence of a gastrointestinal diagnosis or any condition that, in the opinion of the principal investigator, may influence the study outcomes.
- Current diagnosis of a psychiatric disorder.
- Systemic use of antibiotics or steroid medications within the past 3 months.
- Frequent use of NSAIDs (non-steroidal anti-inflammatory drugs) within the 2 months preceding the study visit.
- Regular consumption of prebiotic or probiotic products within the past 4 weeks.
Show all 11Show fewer
- Alcohol or substance abuse.
- Current smoking or use of nicotine pouches.
- Frequent use of laxatives, antidiarrheal agents, or anticholinergic medications within the 12 weeks preceding the study visit.
- Pregnancy or breastfeeding.
- Respiratory disease or infection.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Sweden1 site, 1 recruiting
- Recruiting
Örebro University
Örebro
Natalie Sundberg, fibrematch@oru.se
About this study
Official title: Characterization of Fiber-degrading Microbiota in Individuals Without Gastrointestinal Diseases
The aim of this crossover intervention study is to evaluate the volatile organic compounds (VOCs) present in participants at baseline and how these levels change after consuming either a low- or high-dietary fiber diet for three days. This study will involve adults, 18-65 years old, without any gastrointestinal diseases.
The primary objectives are to characterize baseline VOC profiles, assess changes in these profiles after a short-term dietary fiber intervention, determine if specific VOC patterns correlate with dietary fiber intake, and identify the time points at which VOC levels peak. This information will help establish the optimal timing for breath sampling and potentially provide insight into how VOC patterns relate to dietary fiber consumption and degradation.
Read more
The expected outcome is that a high-dietary fiber diet will produce a VOC profile enriched in metabolites associated with fiber fermentation compared to a low-dietary fiber diet, and that these VOCs will be consistent with those identified in vitro during fecal fermentation. Each participant will serve as an internal control, enabling within-subject comparisons of VOC levels at baseline and following the dietary fiber intervention.
Participants will receive a whole-food product that is rich in dietary fiber and will consume either a low-fiber diet (10 g/day) or a high-fiber diet (40 g/day) for three days. On the first day of each intervention, participants will also ingest a pH capsule to monitor gastrointestinal pH continuously throughout the three days. After a three-week washout period, participants will cross over to the other intervention arm and undergo another round of gastrointestinal pH monitoring.
In addition to the dietary intervention, participants will complete food and health questionnaires to assess habitual fiber intake and dietary habits. Fecal samples will be collected for in vitro fermentation to functionally profile the gut microbiota by assessing fecal VOCs, short-chain fatty acids (SCFA), and the microbial enzymatic activity and its pH-dependent modulation.
- Conditions
- Healthy Adults, Dietary Fiber Fermentation
- Being tested
- Low, High Fiber Diet, High, Low Fiber Diet
- Keywords
- Volatile Organic Compounds, Food Intervention, Healthy participants, No gastrointestinal diseases, Without gastrointestinal diseases, Dietary Fiber
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low, High Fiber DietOther
Dietary Intervention: Low Fiber Diet
Whole food dietary fiber product, 10g of dietary fiber consumed per day for 3 days
Dietary Intervention: High Fiber Diet
Whole food dietary fiber product, 40g of dietary fiber consumed per day for 3 days
High, Low Fiber DietOther
Dietary Intervention: High Fiber Diet
Whole food dietary fiber product, 40g of dietary fiber consumed per day for 3 days
Dietary Intervention: Low Fiber Diet
Whole food dietary fiber product, 10g of dietary fiber consumed per day for 3 days
| Study group | Role | What they receive |
|---|---|---|
| Low Fiber Diet, Then High Fiber Diet | Experimental | Participants will receive a whole food dietary fiber product to consume 10g of dietary fiber per day over a total of 3 days, equal to a high fiber diet. After a washout period of 3 weeks, they then receive the same whole food dietary fiber product, to consume 40g of dietary fiber per day in a total of 3 days, equal to a high fiber diet. Receives: Other: Low, High Fiber Diet |
| High Fiber Diet, Then Low Fiber Diet | Experimental | Participants will receive a whole food dietary fiber product to consume 40g of dietary fiber per day over a total of 3 days, equal to a high fiber diet. After a washout period of 3 weeks, they then receive the same whole food dietary fiber product, to consume 10g of dietary fiber per day in a total of 3 days, equal to a high fiber diet. Receives: Other: High, Low Fiber Diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Effect of a 3-day low fiber diet compared to a 3-day high fiber diet on the Volatile Organic Compound profiles in exhaled breath
Volatile Organic Compound profiles in produced by the 3-day low fiber diet intervention compared to the profiles produced by the 3-day high fiber diet, with a 3-week washout inbetween
Measured: 5 weeks
Secondary outcomes (8)
Effect of a low fiber diet on Volatile Organic Compound profiles after 4 hours
Volatile organic compound profiles 4 hours after the start of the low fiber diet intervention compared with baseline (0 hours)
Measured: 4 hours
Effect of a low fiber diet on Volatile Organic Compound profiles after 6 hours
Volatile organic compound profiles 6 hours after the start of the low fiber diet intervention compared with baseline (0 hours)
Measured: 6 hours
Effect of a low fiber diet on Volatile Organic Compound profiles after 8 hours
Volatile organic compound profiles 8 hours after the start of the low fiber diet intervention compared with baseline (0 hours)
Measured: 8 hours
Effect of a high fiber diet on Volatile Organic Compound profiles after 4 hours
Volatile organic compound profiles 4 hours after the start of the high fiber diet intervention compared with baseline (0 hours)
Measured: 4 hours
Effect of a high fiber diet on Volatile Organic Compound profiles after 6 hours
Volatile organic compound profiles 6 hours after the start of the high fiber diet intervention compared with baseline (0 hours)
Measured: 6 hours
Effect of a high fiber diet on Volatile Organic Compound profiles after 8 hours
Volatile organic compound profiles 8 hours after the start of the high fiber diet intervention compared with baseline (0 hours)
Measured: 8 hours
Gastrointestinal pH after a 3-day low fiber diet
Assessment of Gastrointestinal pH measured by the alpHaONE JSPC-1 pH capsule, after a 3-day low fiber diet
Measured: 5 weeks
Gastrointestinal pH after a 3-day high fiber diet
Assessment of Gastrointestinal pH measured by the alpHaONE JSPC-1 pH capsule, after a 3-day high fiber diet
Measured: 5 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 May 2026
- Study start25 May 2026 (estimated)
- Primary completionNov 2026 (estimated)
- Study completionMar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy AdultsStudies 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Investigator, Outcomes assessor
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Örebro University, Sweden
- Sponsor type
- University, hospital or other
- Collaborators
- University of Helsinki, European Innovation Council
- Responsible party
- Sponsor
- Investigators
- Robert Brummer, Professor, Study director, Örebro University, Sweden
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07594600
- Sponsor's protocol ID
- 2026-00408-01
- Other IDs
- 101161484
- Acronym
- FIBRE-MATCH
- Status last verified
- Jun 2026
- First submitted
- 13 May 2026
- Last updated
- 4 Jun 2026
- 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 4 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Characterization of Fiber-degrading Microbiota in Individuals Without Gastrointestinal Diseases
- ClinicalTrials.gov ID
- NCT07594600
- Acronym / sponsor ID
- FIBRE-MATCH / 2026-00408-01
- Conditions
- Healthy Adults, Dietary Fiber Fermentation
- Keywords
- Volatile Organic Compounds, Food Intervention, Healthy participants, No gastrointestinal diseases, Without gastrointestinal diseases, Dietary Fiber
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- Örebro University, SwedenUniversity, hospital or other
- Collaborators
- University of Helsinki, European Innovation Council
- Study start
- 25 May 2026 (estimated)
- Primary completion
- Nov 2026 (estimated)
- Study completion
- Mar 2027 (estimated)
- First posted
- 19 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.
The aim of this crossover intervention study is to evaluate the volatile organic compounds (VOCs) present in participants at baseline and how these levels change after consuming either a low- or high-dietary fiber diet for three days. This study will involve adults, 18-65 years old, without any gastrointestinal diseases.
The primary objectives are to characterize baseline VOC profiles, assess changes in these profiles after a short-term dietary fiber intervention, determine if specific VOC patterns correlate with dietary fiber intake, and identify the time points at which VOC levels peak. This information will help establish the optimal timing for breath sampling and potentially provide insight into how VOC patterns relate to dietary fiber consumption and degradation.
The expected outcome is that a high-dietary fiber diet will produce a VOC profile enriched in metabolites associated with fiber fermentation compared to a low-dietary fiber diet, and that these VOCs will be consistent with those identified in vitro during fecal fermentation. Each participant will serve as an internal control, enabling within-subject comparisons of VOC levels at baseline and following the dietary fiber intervention.
Participants will receive a whole-food product that is rich in dietary fiber and will consume either a low-fiber diet (10 g/day) or a high-fiber diet (40 g/day) for three days. On the first day of each intervention, participants will also ingest a pH capsule to monitor gastrointestinal pH continuously throughout the three days. After a three-week washout period, participants will cross over to the other intervention arm and undergo another round of gastrointestinal pH monitoring.
In addition to the dietary intervention, participants will complete food and health questionnaires to assess habitual fiber intake and dietary habits. Fecal samples will be collected for in vitro fermentation to functionally profile the gut microbiota by assessing fecal VOCs, short-chain fatty acids (SCFA), and the microbial enzymatic activity and its pH-dependent modulation.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Low Fiber Diet, Then High Fiber Diet | Experimental | Other: Low, High Fiber DietParticipants will receive a whole food dietary fiber product to consume 10g of dietary fiber per day over a total of 3 days, equal to a high fiber diet. After a washout period of 3 weeks, they then receive the same whole food dietary fiber product, to consume 40g of dietary fiber per day in a total of 3 days, equal to a high fiber diet. |
| High Fiber Diet, Then Low Fiber Diet | Experimental | Other: High, Low Fiber DietParticipants will receive a whole food dietary fiber product to consume 40g of dietary fiber per day over a total of 3 days, equal to a high fiber diet. After a washout period of 3 weeks, they then receive the same whole food dietary fiber product, to consume 10g of dietary fiber per day in a total of 3 days, equal to a high fiber diet. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Signed informed consent obtained prior to any study-related procedures.
- Willingness to refrain from regular consumption of prebiotic or probiotic products, as well as medications known to affect gastrointestinal function, for at least four weeks prior to the study visits.
Key exclusion criteria (11 listed)
- History of complicated gastrointestinal surgery.
- Presence of a gastrointestinal diagnosis or any condition that, in the opinion of the principal investigator, may influence the study outcomes.
- Current diagnosis of a psychiatric disorder.
- Systemic use of antibiotics or steroid medications within the past 3 months.
- Frequent use of NSAIDs (non-steroidal anti-inflammatory drugs) within the 2 months preceding the study visit.
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 |
|---|---|---|
| Low, High Fiber DietDietary Intervention: Low Fiber Diet Whole food dietary fiber product, 10g of dietary fiber consumed per day for 3 days Dietary Intervention: High Fiber Diet Whole food dietary fiber product, 40g of dietary fiber consumed per day for 3 days | Other | Low Fiber Diet, Then High Fiber Diet |
| High, Low Fiber DietDietary Intervention: High Fiber Diet Whole food dietary fiber product, 40g of dietary fiber consumed per day for 3 days Dietary Intervention: Low Fiber Diet Whole food dietary fiber product, 10g of dietary fiber consumed per day for 3 days | Other | High Fiber Diet, Then Low Fiber Diet |
Primary outcome
Effect of a 3-day low fiber diet compared to a 3-day high fiber diet on the Volatile Organic Compound profiles in exhaled breath
Time frame: 5 weeks
Volatile Organic Compound profiles in produced by the 3-day low fiber diet intervention compared to the profiles produced by the 3-day high fiber diet, with a 3-week washout inbetween
8 secondary outcomes
Effect of a low fiber diet on Volatile Organic Compound profiles after 4 hours
Time frame: 4 hours
Effect of a low fiber diet on Volatile Organic Compound profiles after 6 hours
Time frame: 6 hours
Effect of a low fiber diet on Volatile Organic Compound profiles after 8 hours
Time frame: 8 hours
Effect of a high fiber diet on Volatile Organic Compound profiles after 4 hours
Time frame: 4 hours
Effect of a high fiber diet on Volatile Organic Compound profiles after 6 hours
Time frame: 6 hours
Effect of a high fiber diet on Volatile Organic Compound profiles after 8 hours
Time frame: 8 hours
Gastrointestinal pH after a 3-day low fiber diet
Time frame: 5 weeks
Gastrointestinal pH after a 3-day high fiber diet
Time frame: 5 weeks
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 4 Jun 2026.
Related trials for Healthy Adults
Not yet recruitingPhase 1
A Phase I Study of GLR2053 Tablets in Chinese Healthy Adult Participants
Atopic Dermatitis
RecruitingPhase 1
First-in-Human Trial to Assess REGN20423 in Healthy Adult Participants and Adult Participants With Atopic Dermatitis
Healthy Volunteer, Atopic Dermatitis
Not yet recruitingPhase 1/2
Clinical Trial to Assess the Safety, Tolerability, Reactogenicity, and Immunogenicity of a 10 Valent Human Papillomavirus Virus (10vHPV) Vaccine
Human Papillomavirus Infection
Not yet recruiting
REM Enhancement Sleep Technology for Well-being, Emotion, and Life Lift
Healthy Adult Participants
Not yet recruitingPhase 1
Safety and Immunogenicity of Chimeric Hemagglutinin mRNA Vaccine Candidates
Influenza
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.
Robert Brummer, Professor study director
Örebro University, Sweden
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Low, High Fiber Diet and High, Low Fiber Diet in people with Healthy Adults and Dietary Fiber Fermentation, run by Örebro University, Sweden at 1 site in Sweden.
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 2 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: looking for participants now, as of the sponsor's last update on 4 Jun 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 Sweden. 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 Natalie Sundberg PhD Student (+46 704670585, natalie.sundberg@oru.se), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Effect of a 3-day low fiber diet compared to a 3-day high fiber diet on the Volatile Organic Compound profiles in exhaled breath (time frame: 5 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 4 Jun 2026.