Effects of a Plant-Based Diet on Gut Health After Colonoscopy

Determining the Impact of Dietary Intervention on Inflammation and Microbiome Composition in Patients With Recurrent Polyps Post-Colonoscopy.

Not applicable Interventional University of California, San Diego · NCT06603519

This study is testing whether a plant-based Mediterranean diet can improve gut health and reduce inflammation in people after they have a colonoscopy.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment30 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity of California, San Diego Academic / other
Locations1 site (San Diego, California)
Trial IDNCT06603519 on ClinicalTrials.gov

What this trial studies

This study investigates how a modified plant-based Mediterranean diet influences gut microbiome composition and inflammation in patients post-colonoscopy. Researchers will analyze stool samples using metagenomic testing to assess gut microorganisms, alongside immune profiling and metabolomic analysis of serum samples. The goal is to understand how dietary changes can enhance gut health and reduce inflammation after bowel preparation for colonoscopy. This multi-faceted approach aims to provide insights into the relationship between diet, gut microbiota, and overall metabolic health.

Who should consider this trial

Good fit: Ideal candidates are individuals scheduled for their second or third colonoscopy with a history of tubular, villous, or serrated polyps but without a current diagnosis of colorectal cancer.

Not a fit: Patients who are pregnant, have serious illnesses, or have difficulty consuming solid or liquid foods may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to dietary recommendations that improve gut health and reduce inflammation in patients undergoing colonoscopy.

How similar studies have performed: Previous studies have shown promising results regarding dietary interventions and gut microbiome health, suggesting potential for success in this approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Due for 2nd or 3rd colonoscopy with prior diagnosis of tubular, villous, or serrated polyps but no current diagnosis of CRC.

Exclusion Criteria:

1. Inability to provide informed consent and engage in informed consent procedures.
2. Participants who suffer from allergic reactions to, or are unwilling to consume, any components of the dietary intervention.
3. Pregnant
4. Serious illness and in hospice or palliative care for terminal disease
5. Swallowing issues, including self-reported difficulty tolerating solids or liquids.
6. Active antibiotics use for an ongoing acute infection.
7. Any disorder, unwillingness, or inability not covered by any other exclusion criteria which, in the investigator's and/or team's opinion jeopardizes the safety of the participant or others or would interfere with adherence to the protocol.
8. Participants who plan to relocate to an area not served by UCSD or travel plans that do not permit completion of the study.
9. Possible ethanol (alcohol) use disorder defined by Alcohol Use Disorders Identification Test (AUDIT) score of \>15

   Uncontrolled disease states:
10. Hyper-tension \>160/100mmHg
11. Exacerbation of underlying gastrointestinal disease, including chronic inflammatory bowel disease or other malabsorptive disorders
12. Decompensated cirrhosis
13. Previously diagnosed Diabetes Mellitus with HbA1c \>9% at screening
14. Newly diagnosed diabetes within the past three months, or HbA1c \>6.5% at screening in a person not previously diagnosed with diabetes.
15. Participants with a history of end-stage renal disease (ESRD) on hemodialysis
16. Active infectious diseases (e.g., active tuberculosis \< 3 months from symptom onset or positive test, COVID \< 1 month from symptom onset or positive test)
17. Participants who require dietary restrictions due to a medical condition or are on a prescribed diet for underlying chronic diseases.
18. Participants with Type 1 or Type 2 diabetes on insulin
19. Participants aged 2: 75 years with Type 2 diabetes taking prescribed medications that can cause hypoglycemia (e.g., sulfonylureas, glinides), or on a prescribed diet
20. Hospitalization for a chronic disease (e.g., congestive heart failure, stroke) within the past three months
21. Requiring transfusions/apheresis during study period
22. Participants with a current diagnosis of, or who have received treatment for, bulimia or anorexia nervosa within the past 3 years
23. Participants with major psychiatric disorders, including major depression, schizophrenia, or psychosis, who have been hospitalized in the past six (6) months or are currently enrolled in treatment programs.
24. Hemoglobin \<9.5 g/dL at screening
25. Myocardial infarction, invasive cardiac procedure, participation in a cardiac or acute rehabilitation programs, transient ischemic attacks, or unstable arrhythmias within the past 3 months.

Where this trial is running

San Diego, California

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Colorectal PolypInflammationDietary InterventionMicrobiotaColorectal NeoplasmsMetabolomicsMicrobiomePolyps
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.