Healthy
Conditions
Keywords
High-Protein, Low-Fiber Diet
Brief summary
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.
Interventions
OTHERHigh-fiber, low-protein diet
Diet will consist of at least 15g fiber above baseline and less than 10% of calories from protein.
OTHERLow-fiber, high-protein diet
Diet will consist of less than 15g fiber and greater than 18% of calories from protein
Sponsors
Mayo Clinic
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Masking description
Principal investigator and analysts will be blinded. The participant will not be told to which diet they are randomized.
Intervention model description
Participants are randomly assigned to either the high-fiber, low protein diet or the low-fiber, high-protein diet.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Urinary Excretion of Lactulose and 13C-Mannitol | 4 weeks | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in gut microbial alpha diversity based on Shannon index | 4 weeks | 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. |
Countries
United States
Outcome results
None listed