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

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.

Study Overview

• Status: Active, not recruiting
• Conditions: Dietary Intervention; Gut Microbiota
• Intervention / Treatment: Other: Pink Beans; Other: Great Northern Beans; Other: Five-Bean Mixture

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.

• Study Type: Interventional
• Enrollment (Estimated): 12
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Nebraska
    • Lincoln, Nebraska, United States, 68588
      • Nebraska Food for Health Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

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

Exclusion Criteria:

1. Has a cardiac device.
2. History of organ transplant
3. 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).
4. Recent history of cancer (excluding skin cancer) in the last year.
5. Current use of tobacco or vaping.
6. Current or recent use (last 3 weeks) of digestive enzymes, laxatives, dietary fiber, prebiotic, or probiotic supplements.
7. Medication or supplement regimen or dosage changed within the last 2 months or 3 weeks, respectively.
8. Taken antibiotics in the last 2 months.
9. Known allergies or intolerances to beans.
10. BMI 18.5-24.9 kg/m2 (normoweight): Current use of oral or injectable medications for the treatment of most chronic conditions.
11. 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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Intervention Scheme 1; Intervention 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	Other: Pink Beans; Pink beans consumed for 2 weeks, at an amount of ½ cup/day for week 1 and 1 ½ cups/day for week 2.; Other: Great Northern Beans; 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.; Other: Five-Bean Mixture; 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.
Active Comparator: Intervention Scheme 2; Intervention 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	Other: Pink Beans; Pink beans consumed for 2 weeks, at an amount of ½ cup/day for week 1 and 1 ½ cups/day for week 2.; Other: Great Northern Beans; 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.; Other: Five-Bean Mixture; 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.
Active Comparator: Intervention Scheme 3; Intervention 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	Other: Pink Beans; Pink beans consumed for 2 weeks, at an amount of ½ cup/day for week 1 and 1 ½ cups/day for week 2.; Other: Great Northern Beans; 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.; Other: Five-Bean Mixture; 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.
Active Comparator: Intervention Scheme 4; Intervention 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	Other: Pink Beans; Pink beans consumed for 2 weeks, at an amount of ½ cup/day for week 1 and 1 ½ cups/day for week 2.; Other: Great Northern Beans; 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.; Other: Five-Bean Mixture; 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.
Active Comparator: Intervention Scheme 5; Intervention 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	Other: Pink Beans; Pink beans consumed for 2 weeks, at an amount of ½ cup/day for week 1 and 1 ½ cups/day for week 2.; Other: Great Northern Beans; 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.; Other: Five-Bean Mixture; 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.
Active Comparator: Intervention Scheme 6; Intervention 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	Other: Pink Beans; Pink beans consumed for 2 weeks, at an amount of ½ cup/day for week 1 and 1 ½ cups/day for week 2.; Other: Great Northern Beans; 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.; Other: Five-Bean Mixture; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	From baseline to end of weeks 1 and 2 of treatment.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	From baseline to end of weeks 1 and 2 of treatment.
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.	From baseline to end of weeks 1 and 2 of treatment.
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]).	From baseline to end of weeks 1 and 2 of treatment.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood pressure	Changes in 24-hour blood pressure as evaluated by an ambulatory blood pressure monitor.	From baseline to the end of treatment at 2 weeks.
Systematic inflammation assessed by C-reactive protein	Changes in circulating levels of C-reactive protein (Unit: mg/L) when collected after fasting.	From baseline to the end of treatment at 2 weeks.
Systematic inflammation assessed by glycosylated acute-phase proteins (GlycA)	Changes in circulating levels of glycosylated acute-phase proteins (Unit: umol/L) when collected after fasting.	From baseline to the end of treatment at 2 weeks.
Glucose metabolism assessed by Homeostasis Model Assessment of Insulin Resistance (HOMA-IR)	Changes in circulating levels of glucose (Unit: mg/dL) and insulin (Unit: uIU/mL) when collected after fasting. Glucose and insulin values will then be used to calculate the Homeostasis Model Assessment of Insulin Resistance using the equation previously described by Matthews and colleagues.	From baseline to the end of treatment at 2 weeks.
Glucose metabolism assessed by C-peptide	Changes in circulating levels of C-peptide (Unit: ng/mL) when collected after fasting.	From baseline to the end of treatment at 2 weeks.
Lipid metabolism assessed by a lipid panel	Changes in circulating levels of total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides (Units: mg/dL) when collected after fasting.	From baseline to the end of treatment at 2 weeks.
Percent body fat assessed by bioelectrical impedance analysis	Changes in percent body fat assessed by an InBody 770 bioelectrical impedance analyzer. The validity of the InBody 770 bioelectrical impedance analyzer has been previously described by Brewer and colleagues.	From baseline to the end of treatment at 2 weeks.

Collaborators and Investigators

• Sponsor: University of Nebraska Lincoln
• Investigators: Principal Investigator: Edward C Deehan, PhD, RD, University of Nebraska Lincoln

Publications and helpful links

General Publications

• 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.
• 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.
• 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.

Study record dates

Study Major Dates

• Study Start (Actual): May 8, 2025
• Primary Completion (Actual): January 28, 2026
• Study Completion (Estimated): April 30, 2027

Study Registration Dates

• First Submitted: March 13, 2025
• First Submitted That Met QC Criteria: April 18, 2025
• First Posted (Actual): April 20, 2025

Study Record Updates

• Last Update Posted (Actual): February 4, 2026
• Last Update Submitted That Met QC Criteria: February 3, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Gut Microbiota; Dry Beans; Nutritional Microbiology
• Other Study ID Numbers: UNL-00024307

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified gut bacteria sequencing data, along with limited participant information, will be uploaded to the National Center for Biotechnology Information Sequence Read Archive.
• IPD Sharing Time Frame: The de-identified gut bacteria sequencing data will be made available upon publication of study findings.
• IPD Sharing Access Criteria: Data will be available for download at the National Center for Biotechnology Information Sequence Read Archive.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No