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Dietary InterventionNCT06935435

Effects of Distinct Nebraska-Dry Bean Market Classes on Gut Microbiota

A study testing Pink Beans, Great Northern Beans and Five-Bean Mixture in people with Dietary Intervention and Gut Microbiota, run by University of Nebraska Lincoln at 1 site in United States.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

Beans are well known for their health benefits. Many of these benefits relate to gut health, as many of the nutrients found in beans support beneficial microbes that live in the gut. However, beans have a lot of genetic diversity. Read more about this study

Who is it for?
Ages 19 to 50 yearsHealthy volunteers can take part
Conditions the study is for
Dietary Intervention, Gut Microbiota
What is being tested?
Pink Beans, Great Northern Beans and Five-Bean Mixture
Could I receive a placebo?
No, everyone receives an active treatment
How many people
12 participants
Where
1 siteUnited States
Study dates
8 May 2025to 30 Apr 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 19 to 50 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Aged 19 to 50 years.
  • Not currently pregnant or planning to become pregnant (Females Only).
  • Stable body mass index (BMI) of either 18.5-24.9 kg/m2 or 27.0-39.9 kg/m2 for the last month.
  • Has not made any major dietary changes in the last month.
  • Able to read and speak English
  • Requires no legally authorized representative (LAR).
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  • Not institutionalized (e.g., prison, psychological treatment center, etc.).
  • Able to wear ambulatory blood pressure monitor and limit physical activity over a 24-hr. period.
  • Have a bowel movement at least every other day.
  • Able to collect and deliver stool samples to Innovation Campus within 4 hours of collection.
  • No known allergies or intolerance to beans.
  • Able to avoid consuming beans during the study, except for the provided beans (up to 1.5 cups/day).

Who cannot join

  • Has a cardiac device.
  • History of organ transplant
  • History of gastrointestinal surgery or disease diagnosed by a physician that involves the stomach, small, and large intestines (e.g., IBD, IBS, chronic constipation, diverticulosis, gastric bypass).
  • Recent history of cancer (excluding skin cancer) in the last year.
  • Current use of tobacco or vaping.
  • Current or recent use (last 3 weeks) of digestive enzymes, laxatives, dietary fiber, prebiotic, or probiotic supplements.
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  • Medication or supplement regimen or dosage changed within the last 2 months or 3 weeks, respectively.
  • Taken antibiotics in the last 2 months.
  • Known allergies or intolerances to beans.
  • BMI 18.5-24.9 kg/m2 (normoweight): Current use of oral or injectable medications for the treatment of most chronic conditions.
  • BMI 27.0-39.9 kg/m2 (overweight): Current use of oral or injectable medications for the treatment of diabetes, hypertension, cardiovascular, liver, kidney, gastrointestinal, or autoimmune.

Trial locations and contacts

1 site in 1 country.

United States1 site
  • Nebraska Food for Health Center

    Lincoln, Nebraska, 68588

Other trials in United States

About this study

Beans are well known for their health benefits. Many of these benefits relate to gut health, as many of the nutrients found in beans support beneficial microbes that live in the gut. However, beans have a lot of genetic diversity. This diversity has led to different bean market classes with different colors, sizes, and nutrient profiles. Differences between bean market classes may trigger different effects on gut microbes and health, but this is poorly understood. The goal of the pilot clinical trial is to make comparisons (1) between two different bean market classes (pink beans, great northern beans) and (2) between a bean mixture (pinto, kidney, black, pink, and great northern beans) and individual bean market classes. The study will assess whether bean market classes differ in their effects on gut microbes, blood pressure, metabolism, and gut symptoms in adults with and without obesity.

Read the detailed description

Bean consumption delivers diverse dietary fibers (resistant starches, non-starch polysaccharides), proteins, polyphenols, and other compounds to the colon, where they serve as substrates for the microbial community (microbiota) that colonizes the gut of humans. However, dry beans exhibit high genetic diversity, corresponding with diverse pigments and nutrients across market classes. It remains poorly understood whether targeted effects on the gut microbiota and health measures are possible with distinct dry bean market classes. The overarching study objective is to perform a randomized, crossover pilot intervention trial in adults to determine the effects of consuming distinct dry bean market classes in isolation or combination on the gut microbiota and health. The study will compare the dose-dependent effects of pink beans, great northern beans, and a five-bean mixture (pinto, kidney, black, pink, and great northern beans) on the gut microbiota, health-relevant metabolites, blood pressure, and immunometabolic markers in adults with and without extra body weight. The pilot study will employ a 3-phase, cross-over design with 2-week intervention periods separated by 2-week washout periods.

Being tested
Pink Beans, Great Northern Beans, Five-Bean Mixture
Keywords
Dry Beans, Gut Microbiota, Nutritional Microbiology

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Pink BeansOther

    Pink beans consumed for 2 weeks, at an amount of ½ cup/day for week 1 and 1 ½ cups/day for week 2.

  • Great Northern BeansOther

    Great northern beans consumed for 2 weeks, at an amount of ½ cup/day for week 1 and 1 ½ cups/day for week 2.

  • Five-Bean MixtureOther

    Five-bean mixture made of pinto, kidney, black, pink, and great northern beans consumed for 2 weeks, at an amount of ½ cup/day for week 1 and 1 ½ cups/day for week 2.

Study groups in NCT06935435
Study groupRoleWhat they receive
Intervention Scheme 1Active comparatorIntervention Phase 1: Week 1: ½ cup Pink Bean → Week 2: 1½ cups Pink Bean Intervention Phase 2: Week 1: ½ cup Great Northern Bean → Week 2: 1½ cups Great Northern Bean Intervention Phase 3: Week 1: ½ cup Bean Mix → Week 2: 1½ cups Bean Mix
Receives: Other: Pink Beans; Other: Great Northern Beans; Other: Five-Bean Mixture
Intervention Scheme 2Active comparatorIntervention Phase 1: Week 1: ½ cup Great Northern Bean → Week 2: 1½ cups Great Northern Bean Intervention Phase 2: Week 1: ½ cup Bean Mix → Week 2: 1½ cups Bean Mix Intervention Phase 3: Week 1: ½ cup Pink Bean → Week 2: 1½ cups Pink Bean
Receives: Other: Pink Beans; Other: Great Northern Beans; Other: Five-Bean Mixture
Intervention Scheme 3Active comparatorIntervention Phase 1: Week 1: ½ cup Bean Mix → Week 2: 1½ cups Bean Mix Intervention Phase 2: Week 1: ½ cup Pink Bean → Week 2: 1½ cups Pink Bean Intervention Phase 3: Week 1: ½ cup Great Northern Bean → Week 2: 1½ cups Great Northern Bean
Receives: Other: Pink Beans; Other: Great Northern Beans; Other: Five-Bean Mixture
Intervention Scheme 4Active comparatorIntervention Phase 1: Week 1: ½ cup Pink Bean → Week 2: 1½ cups Pink Bean Intervention Phase 2: Week 1: ½ cup Bean Mix → Week 2: 1½ cups Bean Mix Intervention Phase 3: Week 1: ½ cup Great Northern Bean → Week 2: 1½ cups Great Northern Bean
Receives: Other: Pink Beans; Other: Great Northern Beans; Other: Five-Bean Mixture
Intervention Scheme 5Active comparatorIntervention Phase 1: Week 1: ½ cup Great Northern Bean → Week 2: 1½ cups Great Northern Bean Intervention Phase 2: Week 1: ½ cup Pink Bean → Week 2: 1½ cups Pink Bean Intervention Phase 3: Week 1: ½ cup Bean Mix → Week 2: 1½ cups Bean Mix
Receives: Other: Pink Beans; Other: Great Northern Beans; Other: Five-Bean Mixture
Intervention Scheme 6Active comparatorIntervention Phase 1: Week 1: ½ cup Bean Mix → Week 2: 1½ cups Bean Mix Intervention Phase 2: Week 1: ½ cup Great Northern Bean → Week 2: 1½ cups Great Northern Bean Intervention Phase 3: Week 1: ½ cup Pink Bean → Week 2: 1½ cups Pink Bean
Receives: Other: Pink Beans; Other: Great Northern Beans; Other: Five-Bean Mixture

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. 16S rRNA gene amplicon sequencing of the fecal bacterial community

    Dose-dependent changes in bacterial composition, and precisely the relative abundance of Faecalibacterium, in fecal samples, as assessed by 16S rRNA gene amplicon sequencing.

    Measured: From baseline to end of weeks 1 and 2 of treatment.

Secondary outcomes (3)
  1. Fecal short-chain fatty acids assessed by gas chromatography

    Dose-dependent changes in fecal concentrations of short-chain fatty acids as determined by gas chromatography.

    Measured: From baseline to end of weeks 1 and 2 of treatment.

  2. Gastrointestinal symptoms assessed by the Gastrointestinal Symptom Rating Scale

    Dose-dependent changes in gastrointestinal symptoms as assessed by the Gastrointestinal Symptom Rating Scale, where the scale is between 0 and 6 and higher values indicate more severe gastrointestinal symptoms.

    Measured: From baseline to end of weeks 1 and 2 of treatment.

  3. Bowel movement habits assessed by a Bowel Habits Questionnaire

    Dose-dependent changes in bowel movement (BM) habits as assessed using a Bowel Habits Questionnaire, which has been previously described by Deehan and colleagues. The questionnaire asks participants to record and describe their BMs over three-days to obtain information on BM frequency (number of BM/day), stool consistency (Bristol Stool Scale, 1 [hard] to 7 [liquid]), perceived stool hardness (1 [soft] to 4 [very hard]), straining during bowel movement, discomfort during bowel movement, sensation of incomplete evacuation (1 [none] to 4 [severe]).

    Measured: From baseline to end of weeks 1 and 2 of treatment.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted20 Apr 2025
  2. Study start8 May 2025
  3. Primary completion28 Jan 2026
  4. Study completion30 Apr 2027 (estimated)

Resources

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
Other
Allocation
Randomised
Intervention model
Crossover
Model description
The study intervention will consist of individuals consuming daily, precooked and prepackaged dry beans over three 2-week intervention periods. The amount of beans to consume will be ½ cups/day during week 1 and 1 ½ cups/day during week 2. The three bean interventions will be i) pink beans, ii) great northern beans, and iii) a five-bean mixture (pinto, kidney, black, pink, and great northern beans). The participants will be asked to consume all bean interventions in random order. The beans will be added to the participants' usual diet.
Masking
None (open label)
Enrolment
12 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06935435
Sponsor's protocol ID
UNL-00024307
Status last verified
Feb 2026
First submitted
13 Mar 2025
Last updated
4 Feb 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Yes: De-identified gut bacteria sequencing data, along with limited participant information, will be uploaded to the National Center for Biotechnology Information Sequence Read Archive.

Publications

  • Deehan EC, Yang C, Perez-Munoz ME, Nguyen NK, Cheng CC, Triador L, Zhang Z, Bakal JA, Walter J. Precision Microbiome Modulation with Discrete Dietary Fiber Structures Directs Short-Chain Fatty Acid Production. Cell Host Microbe. 2020 Mar 11;27(3):389-404.e6. doi: 10.1016/j.chom.2020.01.006. Epub 2020 Jan 30.

    PubMed 32004499
  • Brewer GJ, Blue MNM, Hirsch KR, Saylor HE, Gould LM, Nelson AG, Smith-Ryan AE. Validation of InBody 770 bioelectrical impedance analysis compared to a four-compartment model criterion in young adults. Clin Physiol Funct Imaging. 2021 Jul;41(4):317-325. doi: 10.1111/cpf.12700. Epub 2021 Apr 1.

    PubMed 33752260
  • Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia. 1985 Jul;28(7):412-9. doi: 10.1007/BF00280883.

    PubMed 3899825

Questions about this trial

What is this clinical trial studying?

A study testing Pink Beans, Great Northern Beans and Five-Bean Mixture in people with Dietary Intervention and Gut Microbiota, run by University of Nebraska Lincoln 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 12 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: under way, not looking for participants, as of the sponsor's last update on 4 Feb 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. 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?

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?

16S rRNA gene amplicon sequencing of the fecal bacterial community (time frame: From baseline to end of weeks 1 and 2 of treatment.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06935435, which also lists 3 linked publications.

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 Feb 2026.

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