A Study to Evaluate the Influence of Diet on GI Health

The Influence of Diet on Host Physiology and Disease Across Diverse Human Gut Microbiotas

The purpose of this study is to understand the potential of protein and psyllium fiber to manipulate gut microbial densities, intestinal permeability, and inflammation in humans.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Other: High-fiber, low-protein diet; Other: Low-fiber, high-protein diet

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Minnesota
    • Rochester, Minnesota, United States, 55905
      • Mayo Clinic
    • Rochester, Minnesota, United States, 55905
      • Mayo Clinic in Rochester

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Adults ≥ 18 years old
• On a baseline diet characterized by: Fiber intake of </= 20g/day, > 18% of daily calories from protein

Exclusion Criteria:

• Prior history of gastrointestinal surgeries (except appendectomy and cholecystectomy)
• Known diagnosis of inflammatory bowel disease (Crohn's or ulcerative colitis), microscopic colitis, celiac disease, or other inflammatory GI condition
• Use of tobacco products within the past 6 months (since nicotine may affect intestinal permeability)
• Use of NSAIDs or aspirin and unable or unwilling to stop taking two weeks prior to permeability test and for the duration of the study
• Use of osmotic laxatives and unable or unwilling to stop taking one week prior to permeability test and for the duration of the study
• Use of oral corticosteroids and unable or unwilling to stop use of oral corticosteroids within the previous 6 weeks and for the duration of the study
• Multiple dietary restrictions or unable/unwilling to alter dietary protein or dietary fiber.
• Unwilling to stop ingestion of alcohol and artificial sweeteners such as Splenda™ (sucralose), Nutrasweet™ (aspartame), sorbitol, xylitol, lactulose, or mannitol 2 days before and during the permeability testing days, e.g. foods to be avoided are sugarless gums or mints and diet beverages
• Unwilling to stop stenuous exercise (running >5 miles or equivalent) one week prior to the permeability tests
• Bowel preparation for colonoscopy less than one week prior to completion of the first stool kit and permeability test and flexible sigmoidoscopy and upper endoscopy
• Pregnancy or plan to become pregnant during the study time frame
• Vulnerable adult
• Known bleeding disorders or takes medications that increase risk of bleeding from mucosal biopsies
• Use of oral antibiotic(s) within the past 4 weeks (can be enrolled after 4-week washout period)
• Use of commercial probiotic formulations and unwilling to stop for the duration of the study
• Diagnosis of diabetes
• Any other disease(s), condition(s) or habits(s) that would interfere with completion of study, or in the judgment of the investigator would potentially interfere with compliance to this study or would adversely affect study outcomes

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: High-fiber, low-protein diet; Participants will consume a high-fiber, low-protein diet for at least 4 weeks. All meals will be provided free of charge. No substitutions will be permitted.	Other: High-fiber, low-protein diet; Diet will consist of at least 15g fiber above baseline and less than 10% of calories from protein.
Other: Low-fiber, high-protein diet; Participants will consume a low-fiber, high-protein diet for at least 4 weeks. All meals will be provided free of charge. No substitutions will be permitted.	Other: Low-fiber, high-protein diet; Diet will consist of less than 15g fiber and greater than 18% of calories from protein

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urinary Excretion of Lactulose and 13C-Mannitol	Small Bowel and Colonic Permeability by Urinary Excretion of Lactulose and 13C-Mannitol after Oral Ingestion of lactulose and 13C mannitol (5:1 ratio by mass). The 0-2h urine most closely reflects small intestinal permeability and 8-24h urine reflects colonic permeability. HPLC-tandem mass spectrometry will be used for detection of the sugars. The results will be expressed as the ratio of percentage excretion of the ingested dose of lactulose and mannitol in urine.	4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in gut microbial alpha diversity based on Shannon index	Stool samples will be processed to extract DNA, followed by metagenomic sequencing and assessment of alpha diversity using Shannon index. Comparison will be made using ttest.	4 weeks

Collaborators and Investigators

• Sponsor: Mayo Clinic
• Investigators: Principal Investigator: Purna C. Kashyap, MBBS, Mayo Clinic

Publications and helpful links

Helpful Links

• Mayo Clinic Clinical Trials

Study record dates

Study Major Dates

• Study Start (Actual): June 11, 2021
• Primary Completion (Actual): March 27, 2023
• Study Completion (Actual): March 27, 2023

Study Registration Dates

• First Submitted: February 23, 2021
• First Submitted That Met QC Criteria: March 2, 2021
• First Posted (Actual): March 5, 2021

Study Record Updates

• Last Update Posted (Actual): May 15, 2023
• Last Update Submitted That Met QC Criteria: May 12, 2023
• Last Verified: May 1, 2023

More Information

Terms related to this study

• Keywords: High-Protein, Low-Fiber Diet
• Other Study ID Numbers: 20-008067

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No