Recruiting

Dietary Fiber

Sponsor:

Cornell University

Code:

NCT06777498

Conditions

Body Composition Changes

Body Weight Changes

Eligibility Criteria

Sex: All

Age: 21 - 50

Healthy Volunteers: Accepted

Interventions

Whole Grain Intervention then fruits and vegetables

Fruit and Vegetable Intervention and then whole grains

Study Details

Brief summary:

Dietary fiber has been shown to have beneficial effects on human health through its impact on microbes present in the gut. However, these effects can vary between individuals, and everyone may not reap the same health benefits by eating the same sources of fiber. Factors predicting how an individual's gut microbes as well as the beneficial metabolites produced by these microbes change in response to different sources of fiber would be helpful in developing precision nutrition approaches that maximize the benefits of dietary fiber. The objective of this study is to evaluate candidate predictors of gut microbiota response to fiber sources from either whole grains or fruits and vegetables.

Conditions

Body Composition Changes

Body Weight Changes

Study ID

NCT06777498

Start date

Jan 13, 2025

Status verified date

Jul, 2025

Completion date

Dec 31, 2025

Anticipated

Primary completion date

Oct 1, 2025

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 21 - 50

Healthy Volunteers: Accepted

Inclusion Criteria:

  • Age is between 21-50 years
  • BMI is between 25-30. You can check your BMI here: https://www.cdc.gov/bmi/adult-calculator/index.html
  • Must be able to have height, weight, waist, and hip circumference, and body composition measured during the study
  • Must be able to provide saliva samples.
  • Must be able to provide a phone number and email address at which the study investigators can contact for study-related matters.
  • Must be able to increase dietary fiber intake to the recommended level following the instructions on the USDA MyPlate website: https://www.myplate.gov/myplate-plan
  • Must be able to provide food records of everything consumed (food, beverage, and supplements) on one weekday and one weekend day (example Tuesday, Saturday) every week during the study. This will be done using an online survey.
  • Must be able to provide 10 stool samples over 11 weeks of the study duration. 18) Must have stable weight (within ±3% of usual body weight) for the last two months.
  • Must be able to to take an online survey to assess recent dietary fiber intake to determine eligibility.

Exclusion Criteria:

  • Electronic medical implant, for example, a pacemaker.
  • An existing, UNTREATED, thyroid condition.
  • Use of systemic antibiotics (intravenous injection, intramuscular, or oral) within the last 4 months.
  • An acute disease at the time of enrollment (Acute disease is defined as the presence of a moderate or severe illness with or without fever).
  • A chronic, clinically significant (unresolved, requiring ongoing medical management or medication) pulmonary, cardiovascular, gastrointestinal, hepatic, or renal functional abnormality.
  • Any suspected state of immunosuppression or immunodeficiency including HIV.
  • A history of active UNTREATED gastrointestinal disorders or diseases including

1. Inflammatory bowel disease (IBD)
2. Ulcerative colitis (mild-moderate-severe)
3. Crohn's or celiac disease
4. Indeterminate colitis
5. Irritable bowel syndrome (IBS) (moderate-severe)
6. Persistent, infectious gastroenteritis, colitis or gastritis
7. Persistent or chronic diarrhea of unknown etiology
8. Clostridium difficile infection (recurrent)
9. Chronic constipation
  • Previously had bariatric surgery.
  • An unstable dietary history as defined by major changes in diet during the previous month. For example, elimination or significantly increased intake of a major food group in the diet.
  • Recent history of chronic alcohol consumption defined as more than 5 drinks (or servings) of alcohol per day.
  • Female participants: pregnant/lactating.

Study Design

Enrollment

15 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Supportive Care

Interventions and Outcome Measures

Arms

experimental: Experimental: Group A: Whole grains then fruits and vegetables

Whole grain intervention then fruits and vegetables

experimental: Experimental: Group B: Fruits and vegetables then whole grains

Fruits and vegetables intervention then whole grains

Interventions

Whole Grain Intervention then fruits and vegetables

TREATMENT 1: Participants will eat whole grains that add up to the required daily fiber needs. Investigators will provide participants with these products. Participants will follow this intervention for a set period of time. The beginning of the intervention will include a ramp up phase when they eat half of the daily fiber needs to prevent any gastrointestinal distress from suddenly consuming a higher fiber diet than usual.

TREATMENT 2: Participants will eat fruits and vegetables that add up to the required daily fiber needs. Investigators will provide participants with these products. Participants will follow this intervention for a set period of time. The beginning of the intervention will include a ramp up phase when participants eat half of the daily fiber needs to prevent any gastrointestinal distress from suddenly consuming a higher fiber diet than usual.

Fruit and Vegetable Intervention and then whole grains

TREATMENT 1: Participants will eat fruits and vegetables that add up to the required daily fiber needs. Investigators will provide participants with these products. Participants will follow this intervention for a set period of time. The beginning of the intervention will include a ramp up phase when participants eat half of the daily fiber needs to prevent any gastrointestinal distress from suddenly consuming a higher fiber diet than usual.

TREATMENT 2: Participants will eat whole grains that add up to the required daily fiber needs. Investigators will provide participants with these products. Participants will follow this intervention for a set period of time. The beginning of the intervention will include a ramp up phase when they eat half of the daily fiber needs to prevent any gastrointestinal distress from suddenly consuming a higher fiber diet than usual.

Primary outcome measure

  • Body weight changes [ Time Frame: 3-4 weeks ]
  • Body fat percentage changes [ Time Frame: 3-4 weeks ]

Central Contacts and Locations

Central contacts

Angela Poole

607-255-8796pnnystudy@cornell.edu

Locations

Cornell University

Recruiting

Ithaca, New York, United States, 14850

Contacts

Angela Poole, PhD

607-255-8796pnnystudy@cornell.edu

Principal Investigator:

Angela Poole, PhD

More Information

Sponsor

Cornell University

Last update posted

Jul 11, 2025

Last verified

Jul, 2025

Keywords

  • dietary fiber
  • gut microbiome
  • gut microbiota
  • short-chain fatty acids
  • SCFAs
  • whole grains
  • fruits
  • vegetables

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Cornell University on 2025-07-11.