NCT04666727 · M.D. Anderson Cancer Center
Role of Diet on the Microbiome of the Digestive System
What this study is about
This study is to learn more about how diet affects the microbiome (bacteria and microorganisms) of the digestive system. Researchers want to learn if this, in turn, has an effect on if and how people then develop colorectal cancer.
View original scientific description
This study is to learn more about how diet affects the microbiome (bacteria and microorganisms) of the digestive system. Researchers want to learn if this, in turn, has an effect on if and how people then develop colorectal cancer.
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
- GROUP I: Patients presenting for a screening colonoscopy
- GROUP I: Age of 45 and above
- GROUP I: Strict vegetarian diet, determined by using diet history questionnaire 3.0 National Institutes of Health (NIH)
- GROUP I: Non smoker
- GROUP I: Ability to understand and willingness to sign an informed consent form, complete web based dietary assessment and provide stool, colonic mucosa and blood samples
- GROUP II: Patients presenting for a screening colonoscopy
- GROUP II: Age of 45 and above
- GROUP II: Omnivorous diet
- GROUP II: Non smoker
- GROUP II: Ability to understand and willingness to sign an informed consent form, complete web based dietary assessment and provide stool, colonic mucosa and blood sample
Exclusion criteria
- • Current smokers (nicotine abuse only)
- Positive family history of colon cancer or colon cancer related syndromes
- Recent use of antibiotics in 1 month
- History of inflammatory bowel disease, and/or radiation enteritis or colitis
- Pregnant and breastfeeding women
- Women of child-bearing potential who have positive urine or serum pregnancy test
- Heavy drinker (defined as more than 14 drinks per week)
- Currently using anti-flatulence medications, probiotics and/or fiber supplements
- Major dietary restrictions and/or following a special diet
- Patient with positive fecal test/symptoms
Where
- Houston, Texas
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 May 26, 2026 · Source of record for eligibility and locations