Microbiome DysbiosisCONCOLNCT07093463
Colon-delivered Riboflavin and Gut Microbiota Composition
A study testing Colon-delivered riboflavin, Conventional riboflavin and Microcrystalline Cellulose in people with Microbiome Dysbiosis and Gut Health, run by dsm-firmenich Switzerland AG at 1 site in Germany.
Trial summary
Recent studies suggest B-vitamins such as riboflavin to possess prebiotic-like effects. However, there is still a lack of understanding of the exact host health benefits vs. conventional systemically available vitamin forms. The present study explores the benefit of colon-delivered vitamin B2 vs. Read more about this study
- Who is it for?
- Ages 50 to 70 yearsHealthy volunteers can take part
- Conditions the study is for
- Microbiome Dysbiosis, Gut Health
- What is being tested?
- Colon-delivered riboflavin, Conventional riboflavin and Microcrystalline Cellulose
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 90 participants
- Where
- 1 siteGermany
- Study dates
- 18 Jul 2025to 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 50 to 70 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Individuals providing written informed consent for participation in the study and data processing
- Female and males between 50 and 70 years of age
- For females only: Menopausal as marked by at least 1 year since the last menstrual bleeding
- Individuals with a BMI between 18.5 - 29.9 Kg/m2
- Individuals with stable body weight (≤5% change) over the past 3 months prior to V1
- Individuals with self-reported moderate bowel complaints in at least last 3 months prior to V1
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- Individuals with GSRS score suggestive of moderate bowel complaints, as assessed at V1, for the average condition over the 4 last weeks (all GSRS items have to be answered at V1): • indigestion score 3-5 or constipation score 3-5 or diarrhoea score 3-5
- Individuals with a general good health, as determined by questioning, clinical examination and vital signs (blood pressure, pulse rate) by the investigator at V1
- Individuals willing to avoid consuming gut microbiome modulating dietary supplements, prebiotic, probiotic, synbiotic or fibre-rich supplements during the entire study duration
- Individuals willing to maintain current level of physical activity throughout the entire study duration
- If individuals are taking chronic medications (e.g., antihypertensive medications), they must be willing and expected to maintain the same dosage throughout the study
Who cannot join
- Individuals who are hypersensitive/intolerant to any of the components of the Investigational product or the standardised diet addition (inulin)
- Individuals who have taken systemic antibiotics within the previous 3 months prior to Baseline (V2) or are expected to be taking any during the study
- Individuals who consumed microbiome modulating dietary supplements, prebiotic, probiotic, or fibre-rich supplements within 4 weeks prior to the baseline (V2)
- Individuals who are currently regularly using systemic steroids, proton pump inhibitors, H2 blocker, antacids (however, sporadic use during the study if needed is allowed, but not within 8 hours before each visit), metformin if started less than 6 months prior to V1, or immunosuppressant medication.
- Individuals who have a history of drug abuse in the previous 5 years and/or alcohol abuse at the time of enrolment (>11 units/week for women; >17 units/week for men; unit: approx. 125 mL of wine or similar / approx. 30 mL of spirits
- / approx. 280 mL beer or similar); Is currently in treatment for alcohol/substance abuse; Has been diagnosed with alcohol/substance abuse disorder)
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- Individuals who are a smoker or vaper
- Individuals who are vegetarian or vegan
- Individuals who have made any major dietary changes in the past 3 months prior to Baseline (V2)
- Individuals who have planned major changes in the lifestyle (i.e., diet, dieting, exercise level, significant travel) during the duration of the study.
- Individuals who have a currently present active eating disorder
- Individuals with self-reported food allergy / intolerance (e.g., lactose, gluten, fructose), as determined by the study investigator
- Clinical significance for any of screening laboratory test results from the blood draw at V1, as per investigator's judgement
- Individuals with a self-reported fibre-rich regular diet, as per investigator's judgement
- Individuals who have a (self-reported) gastrointestinal disorder/disease (e.g., chronic/recurrent diarrhoea, inflammatory bowel disorder, irritable bowel syndrome, diverticulosis, stomach or duodenal ulcers, bile acid malabsorption) or previous gastrointestinal surgery (such as bariatric surgery, colon specific surgical interventions etc.), which in the opinion of the investigator would impact the study outcomes
- Individuals with GSRS assessed at V1 for the average condition over the 4 last weeks prior to V1 for any score (abdominal pain, reflux score, indigestion, constipation, diarrhoea) >5 (all GSRS items have to be answered at V1)
- Individuals who have severe or uncontrolled conditions such as type 2 diabetes (FBG ≥ 150 mg/dl from blood draw at V1), psychiatric disorder, respiratory or cardiac illness or any other condition which in the opinion of the investigator would impact the study outcomes
- Individuals who have a history of any gastrointestinal cancer
- Individuals who are severely immunocompromised
- Individuals with alarm features in the past 3 months prior to V1 such as unintentional weight loss (≤5% change), fever, anorectal problems, blood in stool, vomiting
- Individuals who, in the opinion of the investigator are considered to be poor attendees or unlikely for any reason to be able to comply with the study requirements
- If Individuals have been in a recent experimental study, this must have been completed not less than 30 days prior to this study
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Germany1 site, 1 recruiting
- Recruiting
analyze & realize GmbH
Berlin, State of Berlin, 10369
Veronika Bobb, Dr, +49 30 4000 8152, vbobb@a-r.com
About this study
Official title: The Benefit of Colon-delivered Riboflavin (Riboflavin-cd) vs. Conventional Riboflavin on Gut Microbiota Composition and Metabolic Output in Healthy Aging Subjects - a Pilot Proof of Concept Study
Recent studies suggest B-vitamins such as riboflavin to possess prebiotic-like effects. However, there is still a lack of understanding of the exact host health benefits vs. conventional systemically available vitamin forms. The present study explores the benefit of colon-delivered vitamin B2 vs. conventional vitamin B2 in comparison to placebo in an aging population on gut microbiota and metabolic activity as well as gut health.
- Conditions
- Microbiome Dysbiosis, Gut Health
- Being tested
- Colon-delivered riboflavin, Conventional riboflavin, Microcrystalline Cellulose
- Keywords
- elderly, microbiome, colon delivered b-vitamins, riboflavin
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Colon-delivered riboflavinDietary supplement
10 mg of colon-delivered riboflavin
Conventional riboflavinDietary supplement
10 mg of conventional riboflavin
Microcrystalline CelluloseOther
10 mg microcrystalline cellulose
| Study group | Role | What they receive |
|---|---|---|
| Colon-delivered riboflavin | Active comparator | This arm includes 10 mg of colon-delivered riboflavin Receives: Dietary Supplement: Colon-delivered riboflavin |
| Conventional riboflavin | Active comparator | This arm includes 10 mg of conventional riboflavin that will be absorbed in the upper small intestine and not reach the colon Receives: Dietary Supplement: Conventional riboflavin |
| Placebo | Placebo comparator | This arm includes 10 mg of microcrystalline cellulose Receives: Other: Microcrystalline Cellulose |
What is being measured
The primary outcome is the main question the study is designed to answer.
Microbial alpha diversity
Variation D28 - D0 in the faecal microbial alpha diversity (Observed richness, Inverse Simpson index, Shannon index)
Measured: 4 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd)
Secondary outcomes (12)
Microbial alpha diversity
Variation D56 - D0 in the faecal microbial alpha diversity (Observed richness, Inverse Simpson index, Shannon index)
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Microbial composition
Variations D28 - D0 and D56 - D0 in faecal microbial composition, assessed in terms of relative abundance of components at phylum, family, genus and species level and beta diversity (including Jaccard and Bray- Curtis dissimilarity indices)
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Faecal organic acid
Variations D28 - D0 and D56 - D0 in faecal organic acid levels (acetate, propionate, butyrate, valerate, lactate)
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Faecal riboflavin
Variations D28 - D0 and D56 - D0 in faecal concentrations of riboflavin
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Fecal redox potential
Variations D28 - D0 and D56 - D0 in fecal redox potential level
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
fecal pH
Variations D28 - D0 and D56 - D0 in fecal pH
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Fecal calprotectin
Variations D28 - D0 and D56 - D0 in fecal calprotectin
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Plasma Intestinal barrier markers
Variations D28 - D0 and D56 - D0 in plasma intestinal barrier markers (LBP, I-FABP, zonulin and DAO)
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Gastrointestinal complaints
Variations D28 - D0 and D56 - D0 in gastrointestinal complaints assessed by the gastrointestinal Symptom Rating Scale (GSRS) (reflux, abdominal pain, indigestion, diarrhoea, constipation)
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Stool consistency and frequency
Variations D28 - D0 and D56 - D0 in stool consistency as assessed by Bristol Stool Form Scale (BSFS) and frequency
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Quality of life (Short-Form Health Survey (SF-36))
Variations D28 - D0 and D56 - D0 in quality of life as assessed by the Short-Form Health Survey (SF-36)
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Investigational product (IP) perceived benefit
Variations D28 - D0 and D56 - D0 in Investigational product (IP) perceived benefit assessed by a by a 5 point Likert scale
Measured: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Jul 2025
- Study start18 Jul 2025
- Primary completionAug 2026 (estimated)
- Study completionSep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Microbiome DysbiosisStudies 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
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 90 participants (estimated)
Sponsor and investigators
- Lead sponsor
- dsm-firmenich Switzerland AG
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Analyze & Realize
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07093463
- Sponsor's protocol ID
- DSM/230702
- Other IDs
- DSM/011224
- Acronym
- CONCOL
- Status last verified
- Mar 2026
- First submitted
- 22 Jul 2025
- Last updated
- 19 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 19 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Benefit of Colon-delivered Riboflavin (Riboflavin-cd) vs. Conventional Riboflavin on Gut Microbiota Composition and Metabolic Output in Healthy Aging Subjects - a Pilot Proof of Concept Study
- ClinicalTrials.gov ID
- NCT07093463
- Acronym / sponsor ID
- CONCOL / DSM/230702
- Conditions
- Microbiome Dysbiosis, Gut Health
- Keywords
- elderly, microbiome, colon delivered b-vitamins, riboflavin
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 90 participants (estimated)
- Lead sponsor
- dsm-firmenich Switzerland AGIndustry (pharma, biotech, devices)
- Collaborators
- Analyze & Realize
- Study start
- 18 Jul 2025 (actual)
- Primary completion
- Aug 2026 (estimated)
- Study completion
- Sep 2026 (estimated)
- First posted
- 30 Jul 2025 (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.
Recent studies suggest B-vitamins such as riboflavin to possess prebiotic-like effects. However, there is still a lack of understanding of the exact host health benefits vs. conventional systemically available vitamin forms. The present study explores the benefit of colon-delivered vitamin B2 vs. conventional vitamin B2 in comparison to placebo in an aging population on gut microbiota and metabolic activity as well as gut health.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Colon-delivered riboflavin | Active comparator | Dietary Supplement: Colon-delivered riboflavinThis arm includes 10 mg of colon-delivered riboflavin |
| Conventional riboflavin | Active comparator | Dietary Supplement: Conventional riboflavinThis arm includes 10 mg of conventional riboflavin that will be absorbed in the upper small intestine and not reach the colon |
| Placebo | Placebo comparator | Other: Microcrystalline CelluloseThis arm includes 10 mg of microcrystalline cellulose |
Who may qualify
- Ages
- 50 to 70 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (11 listed)
- Individuals providing written informed consent for participation in the study and data processing
- Female and males between 50 and 70 years of age
- For females only: Menopausal as marked by at least 1 year since the last menstrual bleeding
- Individuals with a BMI between 18.5 - 29.9 Kg/m2
- Individuals with stable body weight (≤5% change) over the past 3 months prior to V1
Key exclusion criteria (22 listed)
- Individuals who are hypersensitive/intolerant to any of the components of the Investigational product or the standardised diet addition (inulin)
- Individuals who have taken systemic antibiotics within the previous 3 months prior to Baseline (V2) or are expected to be taking any during the study
- Individuals who consumed microbiome modulating dietary supplements, prebiotic, probiotic, or fibre-rich supplements within 4 weeks prior to the baseline (V2)
- Individuals who are currently regularly using systemic steroids, proton pump inhibitors, H2 blocker, antacids (however, sporadic use during the study if needed is allowed, but not within 8 hours before each visit), metformin if started less than 6 months prior to V1, or immunosuppressant medication.
- Individuals who have a history of drug abuse in the previous 5 years and/or alcohol abuse at the time of enrolment (>11 units/week for women; >17 units/week for men; unit: approx. 125 mL of wine or similar / approx. 30 mL of spirits
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 |
|---|---|---|
| Colon-delivered riboflavin10 mg of colon-delivered riboflavin | Dietary supplement | Colon-delivered riboflavin |
| Conventional riboflavin10 mg of conventional riboflavin | Dietary supplement | Conventional riboflavin |
| Microcrystalline Cellulose10 mg microcrystalline cellulose | Other | Placebo |
Primary outcome
Microbial alpha diversity
Time frame: 4 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd)
Variation D28 - D0 in the faecal microbial alpha diversity (Observed richness, Inverse Simpson index, Shannon index)
12 secondary outcomes
Microbial alpha diversity
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Microbial composition
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Faecal organic acid
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Faecal riboflavin
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Fecal redox potential
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
fecal pH
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Fecal calprotectin
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Plasma Intestinal barrier markers
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Gastrointestinal complaints
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Stool consistency and frequency
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Quality of life (Short-Form Health Survey (SF-36))
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
Investigational product (IP) perceived benefit
Time frame: 8 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd) including 5 g of dietary fiber inulin per day as a standardised addition to the subjects daily diet from week 4 to week 8.
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 19 Mar 2026.
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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 Colon-delivered riboflavin, Conventional riboflavin and Microcrystalline Cellulose in people with Microbiome Dysbiosis and Gut Health, run by dsm-firmenich Switzerland AG at 1 site in Germany.
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 11 inclusion and 22 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 19 Mar 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 Germany. 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. Some participants in this study may receive a placebo. 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 Veronika Bobb, Dr. (+49 30 4000 8152, vbobb@a-r.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Microbial alpha diversity (time frame: 4 weeks' daily consumption of 10 mg of colon delivered riboflavin (riboflavin-cd)). 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 19 Mar 2026.