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Dietary Fiber Effects on the Microbiome and Satiety

This study is looking at how different amounts of dietary fiber affect your gut microbiome (the community of bacteria in your intestines) and feelings of fullness (satiety). Researchers are testing two levels of daily fiber intake: 10-25 grams or 5 grams. They want to see how these fiber levels change the types and numbers of bacteria in your gut, as well as the levels of certain beneficial substances called short chain fatty acids in your blood. You might be able to join if you are between 20 and 55 years old, have a BMI between 25 and 35 (or 40 for Aim 2), and have at least one characteristic of metabolic syndrome (but not diabetes). The study is currently unclear on its recruitment status.

Study design
This is an interventional study planning to enroll 88 participants, comparing two different daily dietary fiber interventions.
What's involved
Participants will need to consume a research diet and provide blood and fecal samples. Samples for microbiome composition and diversity will be taken on specific days during the intervention and at the end.
Compensation
Not stated in the trial record.
Follow-up
Short chain fatty acid concentrations will be measured at the start and end of the intervention. For some participants, additional measurements will occur on day 2 and day 21 of the high fiber intervention.

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NCT04611217

Dietary Fiber Effects on the Microbiome and Satiety

Recruiting
NAAges 20–55InterventionalPrevention
University of Missouri-Columbia
~88 participants
Updated 2025-06-22 on ClinicalTrials.gov
What's tested:Dietary fiber: 10-25gDietary fiber: 5g

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Change in microbiome composition and diversity
Measured over Aim 1: On day 1, on 3 separate days during the intervention and on day 28 of the high fiber or low fiber intervention; Aim 2: within 14 days of scheduled colonoscopy visit and on 7 separate days during the intervention
+2 more outcomes measured

Conditions

Dietary Fiber

Explore related trials

Metabolic Syndrome

Where it's being run

1 sites across 1 states
Missouri1

Who to contact

Katherene OB Anguah, PhD
[email protected]
(573)-882-8966
Email the study team

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Eligibility criteria

Inclusion

Men and women (premenopausal only)
Age 20-55y (Aim 1); 45-55y (Aim 2)
BMI ≥25 or ≤35 kg/m2 (Aim 1); ≥25 or ≤40 (Aim 2)
Weight stable (no fluctuations in body weight of greater than 4 kg in the last 3 months)
Willing to consume a research diet
Willing to provide blood and fecal samples
At least one characteristic of the metabolic syndrome (but not diabetic)
Pre-diabetes acceptable (glucose \<125 mg/dL or HbA1c \<6.5%)
Stably treated with statin drugs, anti-hypertensives, and anti-depressants. These are acceptable as long as the drug category does not alter appetite, body weight, or the microbiome (if known)

Exclusion

Pregnant or lactating
Postmenopausal (evidence suggests an interplay between the gut microbiome)
BMI of \<25 or \>35 kg/m2 (Aim 1); \<25 or \>40 kg/m2 (Aim 2)
Use of medications that affect the gut microbiome (e.g. antibiotics)
Taking medications known to affect appetite (e.g., phentermine) or gastrointestinal function (e.g., metformin)
On a special diet or undergoing weight loss, vegetarian, or other restricted dietary patterns
Ad libitum intake of fiber above 25g/day (mean intake in the US population is 17g/day) and \< 10g/d
Ad libitum alcohol intake of greater than 1 drink/d for women and 2 drinks/d for men
History of disease (example colon cancer, HIV, cardiovascular disease, psychiatric disorders, etc.)
Use of tobacco products
Having metal or implants in the body that are not MRI compatible (Aim 1 only)

What this trial measures

  • Change in microbiome composition and diversityAim 1: On day 1, on 3 separate days during the intervention and on day 28 of the high fiber or low fiber intervention; Aim 2: within 14 days of scheduled colonoscopy visit and on 7 separate days during the intervention

    Fecal samples are collected on different days during the intervention for microbiome analyses using 16rRNA technique

  • Short chain fatty acid concentration in plasmaAt the start and the final day on the intervention for both Aims 1 and 2

    Plasma SCFA are analyzed using gas chromatography/mass spectrometry (GC/MS)

  • Short chain fatty acids enrichmentOn day 2 and day 21 of the high fiber intervention-only for Aim 2

    Subjects are infused with stable isotopes of the short chain fatty acids, acetate, propionate, and butyrate and then isotope dilution by an unlabeled fiber fromt he diet is used to quantify the levels of acetate, propionate and butyrate in vivo