PrediabetesNCT02346838
Prebiotics, Gut Microbiota, and Cardiometabolic Health
A study testing Inulin in people with Prediabetes, run by Virginia Polytechnic Institute and State University at 1 site in United States.
Trial summary
Forty-eight prediabetic men and women (50-75 years of age) will participate in a 6-week feeding study in which they will randomized to receive either 10 g/day of inulin or placebo. Read more about this study
- Who is it for?
- Ages 40 to 70 years
- Conditions the study is for
- Prediabetes
- What is being tested?
- Inulin
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 22 participants
- Where
- 1 siteUnited States
- Study dates
- Jan 2014to Jul 2018
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 40 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Men and women; postmenopausal women not taking hormone replacement therapy.
- Fasting glucose between 5.6 - 6.9 mmol/L and/or a 2h plasma glucose between 7.8-11.1 mmol/L following a 75 g oral glucose tolerance test.
- Weight stable for previous 6 months (+/- 2.0 kg).
- Sedentary to recreationally active
- Willing to be randomized to treatment or placebo.
- Verbal and written informed consent.
- No plans to gain/lose weight or change physical activity level.
- Willing to pick up food daily, and consume foods provided for the 6-week controlled feeding period.
Who cannot join
- BMI less than 25 kg/m2 or greater than 40 kg/m2 or body mass greater than 300 pounds due to limit of DEXA.
- Diabetes or diabetes medications
- Prebiotic or probiotic supplement or product consumption in prior 3 months.
- Total cholesterol > 6.2 mmol/L; triglycerides > 4.5 mmol/L.
- Blood pressure > 140/90 mmHg or antihypertensive medications.
- Diagnosed inflammatory disease (e.g. lupus, irritable bowel, periodontal disease, etc)
Show all 10Show fewer
- Fructo, galacto-, xylo-oligosaccharide intake > 3 g/day.
- Past or current ischemic heart disease, stroke, respiratory disease, endocrine or metabolic disease, neurological disease, or hematological-oncological disease.
- Smoking, alcohol consumption > 2 servings /d for males and 1 serving/d for females, or taking medications (including but not limited to statins or other drugs with anti-inflammatory actions) or antioxidant vitamins or supplements.
- Known allergy, hypersensitivity, or intolerance to inulin.
Trial locations and contacts
1 site in 1 country.
United States1 site
Virginia Polytechnic and State University
Blacksburg, Virginia, 24061
About this study
Official title: The Effect of Prebiotics on Insulin Sensitivity, Metabolic Flexibility, and Cardiovascular Health in Prediabetic Adults.
Forty-eight prediabetic men and women (50-75 years of age) will participate in a 6-week feeding study in which they will randomized to receive either 10 g/day of inulin or placebo. All subjects will be fed an isocaloric diet (50% carbohydrate, 35% fat, 15% protein,) controlled for micronutrient content for 6 weeks to avoid the potential confound of individual differences in diet on gut microbiota. Measurements of intestinal permeability, insulin sensitivity, and skeletal muscle metabolic flexibility will be made prior to and following the controlled feeding period. Stool samples will be collected to assess gut microbial communities.
Read the detailed description
Prebiotics have been defined as "selectively fermented ingredients that result in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring health benefit(s) upon host health". Commonly used prebiotics are inulin-type fructans, fructo-oligosaccharides, xylo-oligosaccharides and galacto-oligosaccharides and while all prebiotics are fibers, not all fibers are prebiotics. The proliferation of a targeted bacterial species, in particular, Bifiodobacterium spp. and Lactobacillus spp. contribute to host cardiometabolic health in many ways including, but not limited to, short chain fatty acid production and, modulation of gut barrier function, endotoxin concentrations, inflammatory pathways, and energy metabolism however, to our knowledge the potential benefits of prebiotic supplementation on cardiometabolic dysfunction has received little attention. Although the concept that dysbiosis of the gut microbiota leads to metabolic endotoxemia and increased risk of cardiometabolic disease is novel, very little information is available in humans. The significance of our proposal includes providing proof of concept efficacy of prebiotic supplementation with inulin on cardiometabolic dysfunction and assessing its relation with changes in gut bacterial communities, intestinal permeability, and metabolic endotoxemia in prediabetes, a condition affecting a substantial segment of the population. Our study could lead to the identification of prebiotic supplementation with inulin as a simple and efficacious strategy for reducing cardiometabolic risk in prediabetes which could change clinical practice by informing dietary recommendations and increasing acceptance of prebiotics by the scientific and medical community.
- Conditions
- Prediabetes
- Being tested
- Inulin, Placebo
- Keywords
- Prediabetes, prebiotics, metabolic endotoxemia
- Medical subject headings
- Prediabetic State
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
InulinDietary supplement
Also called Prebiotic
The treatment will be mixed in orange juice or other beverage and will be consumed at breakfast each day in our metabolic kitchen.
PlaceboDietary supplement
The placebo will be mixed in orange juice or other beverage and will be consumed at breakfast each day in our metabolic kitchen.
| Study group | Role | What they receive |
|---|---|---|
| Inulin | Experimental | Participants will receive 10 g of inulin powder each day for 6 weeks. Receives: Dietary Supplement: Inulin |
| Placebo | Placebo comparator | Participants will receive 10 g of maltodextrin each day for 6 weeks. Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in insulin sensitivity.
Insulin sensitivity will be assessed via a frequently sampled intravenous glucose tolerance test.
Measured: Baseline, 6 weeks
Secondary outcomes (3)
Change in metabolic flexibility.
Metabolic flexibility will be measured in skeletal muscle biopsies prior to and 4 hours following a high fat meal.
Measured: Baseline, 6 weeks
Change in endothelial function.
Flow mediated dilation of the brachial artery will be assessed using duplex ultrasonography with a high resolution linear array transducer according to published guidelines.
Measured: Baseline, 6 weeks
Change in arterial stiffness.
Arterial stiffness will be measured via carotid femoral pulse wave velocity.
Measured: Baseline, 6 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Jan 2015 (estimated)
- Study startJan 2014
- Primary completionDec 2016
- Study completionJul 2018
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PrediabetesStudies 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
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 22 participants (actual)
Sponsor and investigators
- Lead sponsor
- Virginia Polytechnic Institute and State University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Kevin Davy, Virginia Polytechnic Institute and State University
- Investigators
- Kevin P Davy, PhD, Principal investigator, Virginia Polytechnic and State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02346838
- Sponsor's protocol ID
- Prebiotics-Prediabetes
- Status last verified
- Mar 2026
- First submitted
- 7 Jan 2015
- Last updated
- 27 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 27 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Prebiotics on Insulin Sensitivity, Metabolic Flexibility, and Cardiovascular Health in Prediabetic Adults.
- ClinicalTrials.gov ID
- NCT02346838
- Acronym / sponsor ID
- Prebiotics-Prediabetes
- Conditions
- Prediabetes
- Keywords
- Prediabetes, prebiotics, metabolic endotoxemia
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 22 participants (actual)
- Lead sponsor
- Virginia Polytechnic Institute and State UniversityUniversity, hospital or other
- Study start
- Jan 2014
- Primary completion
- Dec 2016 (actual)
- Study completion
- Jul 2018 (actual)
- First posted
- 27 Jan 2015 (estimated)
- 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.
Forty-eight prediabetic men and women (50-75 years of age) will participate in a 6-week feeding study in which they will randomized to receive either 10 g/day of inulin or placebo. All subjects will be fed an isocaloric diet (50% carbohydrate, 35% fat, 15% protein,) controlled for micronutrient content for 6 weeks to avoid the potential confound of individual differences in diet on gut microbiota. Measurements of intestinal permeability, insulin sensitivity, and skeletal muscle metabolic flexibility will be made prior to and following the controlled feeding period. Stool samples will be collected to assess gut microbial communities.
Detailed description
Prebiotics have been defined as "selectively fermented ingredients that result in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring health benefit(s) upon host health". Commonly used prebiotics are inulin-type fructans, fructo-oligosaccharides, xylo-oligosaccharides and galacto-oligosaccharides and while all prebiotics are fibers, not all fibers are prebiotics. The proliferation of a targeted bacterial species, in particular, Bifiodobacterium spp. and Lactobacillus spp. contribute to host cardiometabolic health in many ways including, but not limited to, short chain fatty acid production and, modulation of gut barrier function, endotoxin concentrations, inflammatory pathways, and energy metabolism however, to our knowledge the potential benefits of prebiotic supplementation on cardiometabolic dysfunction has received little attention. Although the concept that dysbiosis of the gut microbiota leads to metabolic endotoxemia and increased risk of cardiometabolic disease is novel, very little information is available in humans. The significance of our proposal includes providing proof of concept efficacy of prebiotic supplementation with inulin on cardiometabolic dysfunction and assessing its relation with changes in gut bacterial communities, intestinal permeability, and metabolic endotoxemia in prediabetes, a condition affecting a substantial segment of the population. Our study could lead to the identification of prebiotic supplementation with inulin as a simple and efficacious strategy for reducing cardiometabolic risk in prediabetes which could change clinical practice by informing dietary recommendations and increasing acceptance of prebiotics by the scientific and medical community.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Inulin | Experimental | Dietary Supplement: InulinParticipants will receive 10 g of inulin powder each day for 6 weeks. |
| Placebo | Placebo comparator | Dietary Supplement: PlaceboParticipants will receive 10 g of maltodextrin each day for 6 weeks. |
Who may qualify
- Ages
- 40 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Men and women; postmenopausal women not taking hormone replacement therapy.
- Fasting glucose between 5.6 - 6.9 mmol/L and/or a 2h plasma glucose between 7.8-11.1 mmol/L following a 75 g oral glucose tolerance test.
- Weight stable for previous 6 months (+/- 2.0 kg).
- Sedentary to recreationally active
- Willing to be randomized to treatment or placebo.
Key exclusion criteria (10 listed)
- BMI less than 25 kg/m2 or greater than 40 kg/m2 or body mass greater than 300 pounds due to limit of DEXA.
- Diabetes or diabetes medications
- Prebiotic or probiotic supplement or product consumption in prior 3 months.
- Total cholesterol > 6.2 mmol/L; triglycerides > 4.5 mmol/L.
- Blood pressure > 140/90 mmHg or antihypertensive medications.
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 |
|---|---|---|
| InulinAlso: PrebioticThe treatment will be mixed in orange juice or other beverage and will be consumed at breakfast each day in our metabolic kitchen. | Dietary supplement | Inulin |
| PlaceboThe placebo will be mixed in orange juice or other beverage and will be consumed at breakfast each day in our metabolic kitchen. | Dietary supplement | Placebo |
Primary outcome
Change in insulin sensitivity.
Time frame: Baseline, 6 weeks
Insulin sensitivity will be assessed via a frequently sampled intravenous glucose tolerance test.
3 secondary outcomes
Change in metabolic flexibility.
Time frame: Baseline, 6 weeks
Change in endothelial function.
Time frame: Baseline, 6 weeks
Change in arterial stiffness.
Time frame: Baseline, 6 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 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. This study is not recruiting at the moment.
Kevin P Davy, PhD principal investigator
Virginia Polytechnic and State University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Inulin in people with Prediabetes, run by Virginia Polytechnic Institute and State University at 1 site in United States.
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 8 inclusion and 10 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: finished, as of the sponsor's last update on 27 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 United States. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in insulin sensitivity. (time frame: Baseline, 6 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 27 Mar 2026.