HealthyNCT06873204
Impact of Soluble Arabinoxylan and Rice Bran Fiber on the Gut Microbiome in Healthy Adults
A study testing Soluble Arabinoxylan and Rice Bran in people with Healthy, run by Purdue University at 1 site in United States.
Trial summary
The importance of the gut microbiota for general health has been recently elucidated, but little is known about the impact of different types of nutrients on the gut microbiota. The soluble fiber in cereal by-products, arabinoxylan (AX), is known to be beneficial for generally promoting gut health. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- Soluble Arabinoxylan and Rice Bran
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 25 participants
- Where
- 1 siteUnited States
- Study dates
- Jul 2025to Oct 2025
- 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 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Men or women.
- Aged between 18-45 years.
- Body mass index between 18.5 and 25 kg/m².
- Able to read/speak English.
Who cannot join
- Gastrointestinal disorders (inflammatory bowel disease, irritable bowel syndrome, gluten sensitivity/intolerance, etc.).
- Those who took antibiotics 3 months before the study.
- Individuals taking regular medication or supplements that might affect the gut microbiota.
- Individuals undertaking weight-loss diets.
- Unstable body weight (±3 kg in the past 3 months), and individuals below 110 lb.
- Heavy drinkers (for men, consuming more than 4 drinks on any day or more than 14 drinks per week; for women, consuming more than 3 drinks on any day or more than 7 drinks per week).
- Smokers (those who have smoked 100 cigarettes in their lifetime and who currently smoke cigarettes, even every day or occasionally).
- Breastfeeding or pregnant women.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site
Clinical Research Center at Purdue University
West Lafayette, Indiana, 47907
Robin L Rhine, 765-494-6275, rrhine@purdue.edu
About this study
Official title: RDA Cereal Fiber Clinical
The importance of the gut microbiota for general health has been recently elucidated, but little is known about the impact of different types of nutrients on the gut microbiota. The soluble fiber in cereal by-products, arabinoxylan (AX), is known to be beneficial for generally promoting gut health. However, it is unclear whether consuming rice bran (RB), the source of AX, is equally helpful or better than consuming the extracted form of AX. This study aims to reveal the potential benefit of insoluble cereal bran fiber ingredients by comparing the effect of soluble arabinoxylan fiber alone and the mostly insoluble rice bran fiber, containing arabinoxylan, on intestinal health and gut microbiota. A placebo (maltodextrin) will be used as a control, with no significant changes expected in this group for the evaluated outcomes.
Participants will:
- Consume two different fiber supplements (soluble arabinoxylan or stabilized rice bran) as well as a placebo (maltodextrin) for 3 weeks each, separated by a 2-week washout period.
- Provide blood and stool samples at six different time points.
- Complete a food and gastrointestinal symptom diary during the intervention periods.
Read the detailed description
Background:
This randomized, crossover clinical trial aims to evaluate the effects of two types of dietary fibers (soluble arabinoxylan and rice bran) compared to a control (maltodextrin) on gut microbiota and intestinal health in healthy adults aged 18-45. Insoluble rice bran, a fiber derived as a cereal by-product, may provide special support of a group of beneficial gut bacteria, and may compare well to its soluble arabinoxylan counterpart. This study will provide insights into whether rice bran, as a fiber source, offers additional benefits compared to the extracted soluble form alone.
Significance:
This study will contribute to the understanding of how different types of cereal fibers, specifically soluble arabinoxylan and rice bran, influence gut microbiota composition and overall intestinal health. The findings will have implications for dietary interventions aimed at promoting gut health, especially in relation to fiber intake from whole food sources compared to extracted fiber components.
Sample size:
25 subjects will be enrolled in the study to have a final number of at least 21, considering a 20% dropout rate.
The study involves three arms:
- Soluble arabinoxylan: Participants will consume 10 grams of soluble arabinoxylan diluted in 200 mL of water, twice daily (morning and evening), for 3 weeks.
- Rice bran: Participants will consume 10 grams of defatted, stabilized rice bran diluted in 200 mL of water, twice daily (morning and evening) for 3 weeks.
- Maltodextrin: Participants will consume 10 grams of maltodextrin diluted in 200 mL of water, twice daily (morning and evening) for 3 weeks.
A two-week washout period will separate the three intervention phases to minimize carryover effects. The order in which participants receive the interventions will be randomized before the study starts.
Study Objectives:
The primary objective is to determine if rice bran fiber promotes the growth of Clostridium cluster IVa, a butyrate-producing bacterial group known to be beneficial for gut health. The secondary objective is to assess differences in the composition of gut microbiota and short-chain fatty acid production among the three interventions. Blood samples will be analyzed for barrier function proteins to further understand how each supplement influences gut integrity.
Study Procedures:
- Screening: Participants will undergo pre-screening via an online questionnaire and those who meet the criteria, will attend an in-person visit for physical measurements (height, weight, and BMI calculation) at the Clinical Research Center at Purdue University. A small amount of blood will be drawn for general health assessment.
- Interventions: Candidates who fully meet the inclusion criteria will be enrolled in the study. Once a week, they will stop at the Department of Food Science at Purdue University to receive sachets containing one of the three supplements described above. Participants will be instructed to consume one sachet in the morning and one in the evening, diluted in water. Each treatment will last for three weeks, followed by a two-week washout period.
- Sample Collection: Biological samples will be collected on the first and the last day of each intervention (days 1, 21, 35, 56, 70, and 91) and include stool and blood collection.
- The participants will be required to fill out a Diet History Questionnaire (DHQ) at the baseline (week 0) and at the end of the study (13th week) to evaluate whether changes in their dietary patterns occurred. 24-hour dietary recalls will also be administered at specific time points during the study to estimate nutrient intake (weeks 0, 1, 2, 3, 5, 6, 7,8, 10, 11, 12, and 13). Lastly, the short form of the International Physical Activity Questionnaire (IPAQ) will be applied at baseline (week 0) and the end of each treatment arm (weeks 3, 8, and 13) to evaluate the participants' physical activity patterns, as well as any eventual shifts throughout the study.
- Additionally, participants will be asked to complete a food and gastrointestinal symptom diary everyday during the intervention periods.
Data Analysis:
Gut microbiota composition will be assessed using DNA sequencing of stool samples, while blood samples will be analyzed for intestinal barrier function markers. Additionally, short-chain fatty acid concentrations in the stool will be measured to understand the metabolic effects of each fiber type on the gut microbiota.
- Conditions
- Healthy
- Being tested
- Soluble Arabinoxylan, Rice Bran, Maltodextrin (Placebo)
- Keywords
- Gut microbiota, Dietary fiber, Soluble arabinoxylan, Rice bran fiber, Intestinal health, Butyrate-producing bacteria, Clostridium cluster IVa, Short-Chain Fatty Acids
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Soluble ArabinoxylanDietary supplement
10 grams of soluble arabinoxylan diluted in 200 mL of water, twice daily for 3 consecutive weeks.
Rice BranDietary supplement
10 grams of rice bran fiber diluted in 200 mL of water, twice daily for 3 consecutive weeks.
Maltodextrin (Placebo)Dietary supplement
10 grams of maltodextrin diluted in 200 mL of water, twice daily for 3 consecutive weeks.
| Study group | Role | What they receive |
|---|---|---|
| Soluble Arabinoxylan | Experimental | Participants in this arm will receive soluble arabinoxylan for 3 consecutive weeks. Receives: Dietary Supplement: Soluble Arabinoxylan |
| Rice Bran | Experimental | Participants in this arm will consume rice bran fiber for 3 consecutive weeks. Receives: Dietary Supplement: Rice Bran |
| Maltodextrin | Placebo comparator | Participants in this arm will consume maltodextrin for 3 consecutive weeks. Receives: Dietary Supplement: Maltodextrin (Placebo) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Comparison of two test fibers (insoluble cereal bran and soluble arabinoxylan) and a control (maltodextrin) on gut beneficial bacteria
The primary outcome of the study is change in butyrogenic Clostridium cluster XIVa gut bacteria.
Measured: From enrollment to the end of treatment at 13 weeks.
Secondary outcomes (1)
Comparison of two tests (insoluble cereal bran and soluble arabinoxylan) and a control (maltodextrin) on fecal butyrate and intestinal barrier function
Secondary outcomes are fecal butyrate, gut barrier function protein (serum zonulin), and serum lipopolysaccharide-binding protein (LBP)
Measured: From enrollment to the end of treatment at 13 weeks.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Mar 2025
- Study startJul 2025 (estimated)
- Primary completionOct 2025 (estimated)
- Study completionOct 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies 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
- Model description
- Randomized, crossover, double-blind, clinical trial (RCT).
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 25 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Purdue University
- Sponsor type
- University, hospital or other
- Collaborators
- Rural Development Administration (RDA) of the Republic of Korea
- Responsible party
- Principal investigator, Bruce R. Hamaker, Purdue University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06873204
- Sponsor's protocol ID
- IRB-2024-881
- Status last verified
- Jun 2025
- First submitted
- 6 Mar 2025
- Last updated
- 29 Jun 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 29 Jun 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- RDA Cereal Fiber Clinical
- ClinicalTrials.gov ID
- NCT06873204
- Acronym / sponsor ID
- IRB-2024-881
- Conditions
- Healthy
- Keywords
- Gut microbiota, Dietary fiber, Soluble arabinoxylan, Rice bran fiber, Intestinal health, Butyrate-producing bacteria, Clostridium cluster IVa, Short-Chain Fatty Acids
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 25 participants (estimated)
- Lead sponsor
- Purdue UniversityUniversity, hospital or other
- Collaborators
- Rural Development Administration (RDA) of the Republic of Korea
- Study start
- Jul 2025 (estimated)
- Primary completion
- Oct 2025 (estimated)
- Study completion
- Oct 2025 (estimated)
- First posted
- 12 Mar 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.
The importance of the gut microbiota for general health has been recently elucidated, but little is known about the impact of different types of nutrients on the gut microbiota. The soluble fiber in cereal by-products, arabinoxylan (AX), is known to be beneficial for generally promoting gut health. However, it is unclear whether consuming rice bran (RB), the source of AX, is equally helpful or better than consuming the extracted form of AX. This study aims to reveal the potential benefit of insoluble cereal bran fiber ingredients by comparing the effect of soluble arabinoxylan fiber alone and the mostly insoluble rice bran fiber, containing arabinoxylan, on intestinal health and gut microbiota. A placebo (maltodextrin) will be used as a control, with no significant changes expected in this group for the evaluated outcomes.
Participants will:
- Consume two different fiber supplements (soluble arabinoxylan or stabilized rice bran) as well as a placebo (maltodextrin) for 3 weeks each, separated by a 2-week washout period.
- Provide blood and stool samples at six different time points.
- Complete a food and gastrointestinal symptom diary during the intervention periods.
Detailed description
Background:
This randomized, crossover clinical trial aims to evaluate the effects of two types of dietary fibers (soluble arabinoxylan and rice bran) compared to a control (maltodextrin) on gut microbiota and intestinal health in healthy adults aged 18-45. Insoluble rice bran, a fiber derived as a cereal by-product, may provide special support of a group of beneficial gut bacteria, and may compare well to its soluble arabinoxylan counterpart. This study will provide insights into whether rice bran, as a fiber source, offers additional benefits compared to the extracted soluble form alone.
Significance:
This study will contribute to the understanding of how different types of cereal fibers, specifically soluble arabinoxylan and rice bran, influence gut microbiota composition and overall intestinal health. The findings will have implications for dietary interventions aimed at promoting gut health, especially in relation to fiber intake from whole food sources compared to extracted fiber components.
Sample size:
25 subjects will be enrolled in the study to have a final number of at least 21, considering a 20% dropout rate.
The study involves three arms:
- Soluble arabinoxylan: Participants will consume 10 grams of soluble arabinoxylan diluted in 200 mL of water, twice daily (morning and evening), for 3 weeks.
- Rice bran: Participants will consume 10 grams of defatted, stabilized rice bran diluted in 200 mL of water, twice daily (morning and evening) for 3 weeks.
- Maltodextrin: Participants will consume 10 grams of maltodextrin diluted in 200 mL of water, twice daily (morning and evening) for 3 weeks.
A two-week washout period will separate the three intervention phases to minimize carryover effects. The order in which participants receive the interventions will be randomized before the study starts.
Study Objectives:
The primary objective is to determine if rice bran fiber promotes the growth of Clostridium cluster IVa, a butyrate-producing bacterial group known to be beneficial for gut health. The secondary objective is to assess differences in the composition of gut microbiota and short-chain fatty acid production among the three interventions. Blood samples will be analyzed for barrier function proteins to further understand how each supplement influences gut integrity.
Study Procedures:
- Screening: Participants will undergo pre-screening via an online questionnaire and those who meet the criteria, will attend an in-person visit for physical measurements (height, weight, and BMI calculation) at the Clinical Research Center at Purdue University. A small amount of blood will be drawn for general health assessment.
- Interventions: Candidates who fully meet the inclusion criteria will be enrolled in the study. Once a week, they will stop at the Department of Food Science at Purdue University to receive sachets containing one of the three supplements described above. Participants will be instructed to consume one sachet in the morning and one in the evening, diluted in water. Each treatment will last for three weeks, followed by a two-week washout period.
- Sample Collection: Biological samples will be collected on the first and the last day of each intervention (days 1, 21, 35, 56, 70, and 91) and include stool and blood collection.
- The participants will be required to fill out a Diet History Questionnaire (DHQ) at the baseline (week 0) and at the end of the study (13th week) to evaluate whether changes in their dietary patterns occurred. 24-hour dietary recalls will also be administered at specific time points during the study to estimate nutrient intake (weeks 0, 1, 2, 3, 5, 6, 7,8, 10, 11, 12, and 13). Lastly, the short form of the International Physical Activity Questionnaire (IPAQ) will be applied at baseline (week 0) and the end of each treatment arm (weeks 3, 8, and 13) to evaluate the participants' physical activity patterns, as well as any eventual shifts throughout the study.
- Additionally, participants will be asked to complete a food and gastrointestinal symptom diary everyday during the intervention periods.
Data Analysis:
Gut microbiota composition will be assessed using DNA sequencing of stool samples, while blood samples will be analyzed for intestinal barrier function markers. Additionally, short-chain fatty acid concentrations in the stool will be measured to understand the metabolic effects of each fiber type on the gut microbiota.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
- Model description
- Randomized, crossover, double-blind, clinical trial (RCT).
| Arm | Type | Receives |
|---|---|---|
| Soluble Arabinoxylan | Experimental | Dietary Supplement: Soluble ArabinoxylanParticipants in this arm will receive soluble arabinoxylan for 3 consecutive weeks. |
| Rice Bran | Experimental | Dietary Supplement: Rice BranParticipants in this arm will consume rice bran fiber for 3 consecutive weeks. |
| Maltodextrin | Placebo comparator | Dietary Supplement: Maltodextrin (Placebo)Participants in this arm will consume maltodextrin for 3 consecutive weeks. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Men or women.
- Aged between 18-45 years.
- Body mass index between 18.5 and 25 kg/m².
- Able to read/speak English.
Key exclusion criteria (8 listed)
- Gastrointestinal disorders (inflammatory bowel disease, irritable bowel syndrome, gluten sensitivity/intolerance, etc.).
- Those who took antibiotics 3 months before the study.
- Individuals taking regular medication or supplements that might affect the gut microbiota.
- Individuals undertaking weight-loss diets.
- Unstable body weight (±3 kg in the past 3 months), and individuals below 110 lb.
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 |
|---|---|---|
| Soluble Arabinoxylan10 grams of soluble arabinoxylan diluted in 200 mL of water, twice daily for 3 consecutive weeks. | Dietary supplement | Soluble Arabinoxylan |
| Rice Bran10 grams of rice bran fiber diluted in 200 mL of water, twice daily for 3 consecutive weeks. | Dietary supplement | Rice Bran |
| Maltodextrin (Placebo)10 grams of maltodextrin diluted in 200 mL of water, twice daily for 3 consecutive weeks. | Dietary supplement | Maltodextrin |
Primary outcome
Comparison of two test fibers (insoluble cereal bran and soluble arabinoxylan) and a control (maltodextrin) on gut beneficial bacteria
Time frame: From enrollment to the end of treatment at 13 weeks.
The primary outcome of the study is change in butyrogenic Clostridium cluster XIVa gut bacteria.
1 secondary outcome
Comparison of two tests (insoluble cereal bran and soluble arabinoxylan) and a control (maltodextrin) on fecal butyrate and intestinal barrier function
Time frame: From enrollment to the end of treatment at 13 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 29 Jun 2025.
- Individual participant dataSharing planned: Undecided
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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 Soluble Arabinoxylan and Rice Bran in people with Healthy, run by Purdue 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 4 inclusion and 8 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 29 Jun 2025. 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?
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 Bruce R Hamaker, Ph.D. (765-494-5668, hamakerb@purdue.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Comparison of two test fibers (insoluble cereal bran and soluble arabinoxylan) and a control (maltodextrin) on gut beneficial bacteria (time frame: From enrollment to the end of treatment at 13 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 29 Jun 2025.