NCT04611217 · University of Missouri-Columbia
Dietary Fiber Effects on the Microbiome and Satiety
(FEMS)
What this study is about
Strong evidence supports the association between high fiber (HiFi) diets (e.g. legumes, nuts, vegetables) and a reduced risk for chronic conditions such as cardiovascular disease (CVD), type 2 diabetes and some forms of cancer. However, the current U.S. average consumption of dietary fiber of 17g/day is significantly below the recommendation level of 25g/d for women and 38g/d for men.
View original scientific description
Strong evidence supports the association between high fiber (HiFi) diets (e.g. legumes, nuts, vegetables) and a reduced risk for chronic conditions such as cardiovascular disease (CVD), type 2 diabetes and some forms of cancer. However, the current U.S. average consumption of dietary fiber of 17g/day is significantly below the recommendation level of 25g/d for women and 38g/d for men. Furthermore, fiber fermentation to produce short chain fatty acid (SCFA) products and alterations in microbial composition and activity may be mechanisms linking a HiFi diet to improved health. Importantly, much of the data, including findings supporting a beneficial role of SCFA have been derived from animal studies. Human studies are now needed to advance the understanding of the translational significance of rodent studies and the potential benefit of fiber on microbial metabolites and cardiometabolic health, glucose regulation, appetite and satiety. The central hypothesis is that that the mechanisms by which dietary fiber provides metabolic benefit include direct physical effects in the upper gastrointestinal tract to slow nutrient absorption, and indirect effects to reduce food intake mediated by SCFA-induced secretion of intestinal hormones resulting in increased satiety. Design: Using fiber derived from peas, Aim 1 will test the effect of a HiFi diet on appetite, satiety, and cardiometabolic health and whether elevated SCFA concentration mediates improved satiety in 44 overweight/obese subjects randomly assigned to receive either a high fiber or a low fiber dietary intervention for four weeks in a parallel arm-repeated measures design. Aim 2 will quantitate the changes in microbial composition and colonic SCFA production rate during HiFi feeding and whether any changes are potential mediators of observed benefits on satiety and cardiometabolic risk factors in 26 subjects assigned to receive a high fiber intervention for 3 weeks in a repeated measures design. Relevance: These studies will significantly expand the understanding of mechanisms by which dietary fiber improves satiety and cardiometabolic health in humans.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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) 1\. A large waistline: 35 inches or more for women 40 inches or more for men 2. High triglycerides: 150 mg/dL or higher 3. Low HDLc level: \<50 mg/dL for women \<40 mg/dL for men 4. High blood pressure ≥130/85 mmHg 5. Fasting blood sugar ≥100 mg/dL
- 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 criteria
- 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)
Where
- Columbia, Missouri
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 22, 2025 · Source of record for eligibility and locations