Effects of Riboflavin on Faecalibacterium Prausnitzii and the Gut Microbiota

Study Overview
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Brief Summary
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The purpose of this trial is to investigate comprehensively the effect of riboflavin supplementation on the abundance of F. prausnitzii and on other members of the gut microbiota in faeces of healthy volunteers. Additionally it will be assessed whether riboflavin supplementation affects the abundance of potentially pathogenic bacteria such as adherent invasive E. coli (AIEC). Finally, the effect of riboflavin supplementation on the production of Short Chain Fatty Acids, the release of gut hormones and potential changes in glucose homeostasis and appetite perception will be assessed.

Official Title
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Effects of Oral Riboflavin Supplementation on the Growth of Faecalibacterium Prausnitzii and the Impact on the Gut Microbiota: A Randomized, Double-blind, Placebo-controlled Human Intervention Trial

Conditions
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Gut Microbiota

Intervention / Treatment
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* Dietary Supplement: Riboflavin Dose 1
* Dietary Supplement: Riboflavin Dose 2
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Males or Females, age 20 - 60 years Participant is willing to stick to his/her normal habitual diet excluding consumption of any unusual high energy-rich or fat-rich meals or prolonged fasting, etc. throughout the study period Participant is willing to maintain his/her habitual physical activity patterns throughout the study period Participant has been stable in body-weight within the last 6 months Participant has no health conditions that would prevent him/her from fulfilling the study requirements as judged by the investigator on the basis of medical history and routine laboratory test results Participant has a body mass index (BMI) of ≥18.5 and ≤ 24.9 kg/m2 at screening Participant is willing to refrain from consuming alcoholic drinks 24 h prior to test days (V2 - V3) Participant is not smoking Participant is able and motivated to comply with protocol requirements like for instance take the investigational product the way it is prescribed and to do the tests Participant understands the study procedures and signs forms providing informed consent to participate in the study Exclusion Criteria: Participant has abnormal clinical chemistry and haematology laboratory test results of clinical significance that in the judgment of the investigator would interfere with the participant's ability to comply with the study protocol (which might confound the interpretation of the study results), or put the participant at undue risk Participants with a history of GI disorders that are likely to interfere with the mode of action of the test product Participant has donated more than 300 mL of blood during the three months prior to screening Participant has a history, in the judgment of the investigator, of a psychological illness or condition such as to interfere with the participant's ability to understand the requirements of the study Use of antibiotics or signs of active systemic infection in the last 6 months Participants who are on hypocaloric/hypercaloric diet aiming for weight loss/gain Participant has a history or presence of cancer in the prior two years, except for non-melanoma skin cancer Participant is pregnant, planning to be pregnant during the study period, lactating, or women of childbearing potential who are unwilling to commit to the use of a medically approved form of contraception throughout the study period. The method of contraception must be recorded in the source documentation Regular use of dietary supplements e.g. riboflavin, fish oil, 1 month prior to study inclusion Participant has had exposure to any non-registered drug product within 30 days prior to the screening visit Recent history of (within 12 months of screening visit) or strong potential for alcohol or substance abuse. Alcohol abuse is defined as >60g (men) / 40g (women) pure alcohol per day (1.5 l / 1 l beer resp. 0.75 l / 0.5 l wine) Participant has a known allergy or sensitivity to study product or any ingredients of the study product or meals provided Use of commercially available probiotic, prebiotic and other supplements that may affect the gut microbiota

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Riboflavin Dose 1<br>100 mg Riboflavin (one capsule) per day for 2 weeks | Dietary Supplement: Riboflavin Dose 1<br> <br> * Other names: Vitamin B2;|
| Experimental: Riboflavin Dose 2<br>50 mg Riboflavin (one capsule) per day for 2 weeks | Dietary Supplement: Riboflavin Dose 2<br> <br> * Other names: Vitamin B2;|
| Placebo Comparator: Placebo<br>100 mg starch plus 0,5% silica (one capsule) per day for 2 weeks | Other: Placebo<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of F. prausnitzii per gram faeces | To determine the effect of 2 weeks oral riboflavin supplementation (50 and 100 mg/day) on the number of F. prausnitzii per gram faeces in comparison with placebo | 2 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bacterial composition (diversity and quantity of anaerobic microbiota) per gram faeces | To determine the effects of 2 weeks oral riboflavin supplementation (50 and 100 mg/day) on bacterial composition (diversity and quantity of anaerobic microbiota) in comparison with placebo | 2 weeks | 
| Production of short chain fatty acids (SCFA) in faeces | To determine the effects of 2 weeks oral riboflavin supplementation (50 and 100 mg/day) on the production of short chain fatty acids (SCFA) in faeces in comparison with placebo | 2 weeks | 
| Gastrointestinal (GI) comfort (bloating, flatulence) | To determine the effects of 2 weeks oral riboflavin supplementation (50 and 100 mg/day) on gastrointestinal (GI) comfort (bloating, flatulence) in comparison with placebo using validated visual analogue scale (VAS) questionnaires | 2 weeks | 
| Oral Glucose Tolerance Test: blood glucose | In a subgroup of participants, to determine the effects of 2 weeks oral riboflavin supplementation (50 and 100 mg/day) on blood glucose, and plasma insulin, GLP-1, GLP-2 and ghrelin as well as appetite feelings during an oral glucose tolerance test (oGTT) in comparison with placebo | 2 weeks | 
| Oral Glucose Tolerance Test: plasma insulin | In a subgroup of participants, to determine the effects of 2 weeks oral riboflavin supplementation (50 and 100 mg/day) on blood glucose, and plasma insulin, GLP-1, GLP-2 and ghrelin as well as appetite feelings during an oral glucose tolerance test (oGTT) in comparison with placebo | 2 weeks | 
| Oral Glucose Tolerance Test: Glucagon-like Peptide 1 (GLP-1) | In a subgroup of participants, to determine the effects of 2 weeks oral riboflavin supplementation (50 and 100 mg/day) on blood glucose, and plasma insulin, GLP-1, GLP-2 and ghrelin as well as appetite feelings during an oral glucose tolerance test (oGTT) in comparison with placebo | 2 weeks | 
| Oral Glucose Tolerance Test: Glucagon-like Peptide 2 (GLP-2) | In a subgroup of participants, to determine the effects of 2 weeks oral riboflavin supplementation (50 and 100 mg/day) on blood glucose, and plasma insulin, GLP-1, GLP-2 and ghrelin as well as appetite feelings during an oral glucose tolerance test (oGTT) in comparison with placebo | 2 weeks | 
| Oral Glucose Tolerance Test: ghrelin | In a subgroup of participants, to determine the effects of 2 weeks oral riboflavin supplementation (50 and 100 mg/day) on blood glucose, and plasma insulin, GLP-1, GLP-2 and ghrelin as well as appetite feelings during an oral glucose tolerance test (oGTT) in comparison with placebo | 2 weeks | 
| Oral Glucose Tolerance Test: Appetite feelings during the test | In a subgroup of participants, to determine the effects of 2 weeks oral riboflavin supplementation (50 and 100 mg/day) on blood glucose, and plasma insulin, GLP-1, GLP-2 and ghrelin as well as appetite feelings during an oral glucose tolerance test (oGTT) in comparison with placebo | 2 weeks | 
| Changes in stool characteristics: faeces pH | To determine the possible changes in stool characteristics such as faeces pH upon riboflavin supplementation | 2 weeks | 
| Changes in stool characteristics: dry weight | To determine the possible changes in stool characteristics such as dry weight upon riboflavin supplementation | 2 weeks | 
| Changes in gut permeability related biomarkers: fatty-acid-binding proteins (I-FABP (plasma)) | To determine any possible effect on gut permeability, assessment of permeability related biomarkers: fatty-acid-binding proteins (I-FABP (plasma)) and SM-22 (serum) upon riboflavin supplementation | 2 weeks | 
| Changes in gut permeability related biomarkers: SM-22 (serum) | To determine any possible effect on gut permeability, assessment of permeability related biomarkers: fatty-acid-binding proteins (I-FABP (plasma)) and SM-22 (serum) upon riboflavin supplementation | 2 weeks | 
| Riboflavin concentration in faeces | To determine the effects of 2 weeks oral riboflavin supplementation on riboflavin concentration in faeces and plasma | 2 weeks | 
| Riboflavin concentration in plasma | To determine the effects of 2 weeks oral riboflavin supplementation on riboflavin concentration in faeces and plasma | 2 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gut Microbiota, Riboflavin, Vitamin B2, oGTT, Faecalibacterium prausnitzii