Effects of Replacing High Protein Foods in People With Chronic Kidney Disease

Not Applicable

Not yet recruiting

• Conditions: Chronic Kidney Disease Stage 3

• Registration Number: NCT07105670
• Lead Sponsor: Indiana University

Brief Summary

The goal of this crossover clinical trial is to explore the effects of red meat intake on serum and fractional urinary excretion of uremic toxins including trimethylamine N-oxide in people with chronic kidney disease.

Detailed Description

This study will be a single-blind crossover, human-feeding study comparing 3 weeks of a lacto-ovo vegetarian diet to the same diet with 20% of the protein replaced by red meat. There will be a 2-week baseline period and a 5-week washout period where participants will consume their typical, self-selected diet. Once eligible, the participant will be randomized to a diet order. The investigators will recruit up to 15 participants. Descriptive statistics (means and standard deviations) will be used to summarize the characteristics of the study population. In general, data will be analyzed using linear mixed-effect models to account for the potential correlation among measurements from the same participant. A power analysis of this pilot study will be conducted based on the estimated interparticipant and intraparticipant variabilities to estimate the required number of participants to detect a certain size of difference with a certain power for a full study.

Study Timeline

• Study First Submitted: 2025-07-30
• Study First Submitted QC: 2025-07-30
• Status Verified: 2025-08
• Study Start: 2025-08-01
• Last Update Submitted: 2025-08-05
• Study First Posted: 2025-08-06
• Last Update Posted: 2025-08-11
• Primary Completion: 2026-06-30
• Study Completion: 2026-06-30

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 15

Inclusion Criteria

• Age 40-70 years
• Male or postmenopausal female
• Stage 3 CKD (eGFR between 30-59ml/min/1.73m^2 by the CKD-EPI equation (without race correction)).
• If eGFR is greater than or equal to 45ml/min/1.73m^2 then albuminuria must be greater than 300mg/g creatinine by spot urine.
• Willing to consume controlled diet for duration of the study
• Willing to collect fecal samples at home

Exclusion Criteria

• Hemoglobin A1c greater than 7% within previous six months
• Treatment with metformin or insulin within previous three months
• Blood pressure greater than 150/100 mmHg from chart of home on at least two occasions in prior month (can be inclusive of screening visit)
• Change in cardiovascular and/or hypertension medication in the last 30 days
• History of major gastrointestinal disease (e.g. inflammatory bowel disease, uncontrolled irritable bowel syndrome, C. difficile chronic infection, celiac disease, diverticulitis, stomach or duodenal ulcers)
• Known HIV disease
• Hospitalization in the last two months
• Significant recent unintentional weight loss (5% of weight over past three months)
• Cancer or received cancer treatment in the last year (except basal cell carcinoma)
• Prior bariatric surgery (i.e. gastric bypass, sleeve gastrectomy) or restrictive bariatric surgery (i.e. adjustable gastric band)
• Treatment with immunosuppressive medications in the past six months or more than one week of treatment with prednisone greater than 10mg per day in the past three months (or equivalent steroid dose of non-prednisone steroids)
• Recent antibiotic use defined as a single course of antibiotics within the past three months or two or more courses within the past six months
• Known food allergy that would influence the ability to consume the study diets
• History of hyperkalemia defined as greater than 5.5mmol/L on at least two occasions
• Other medical conditions or concerns at the discretion of the investigators

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Serum trimethylamine N-oxide	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).	Intra- and interparticipant variability of serum concentrations as measured by high performance liquid chromatography-mass spectrometry

Secondary Outcome Measures

Name	Time	Method
Additional serum uremic toxins	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).	Including p-cresyl sulfate and indoxyl sulfate measured by high performance liquid chromatography-mass spectrometry
Urinary excretion of uremic toxins	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).	Measured by a ratio of serum and urine values
Gut microbiota	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).	Diversity and composition of the gut microbiome
Gastrointestinal symptoms	13 Weeks (collections in week 2, 5, 10, and 13 which corresponds to before and during the last week of each of the three-week controlled diet periods).	Measured at the end of each study period by the Gastrointestinal Symptom Rating Scale. This is a 15-item questionnaire that includes five domains. Each item is scored from 1 to 7 and the mean score in each domain is presented.
Stool consistency	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).	Measured on a scale from 1 to 7 using the Bristol Stool Scale/Chart.
Blood pressure	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Arterial Stiffness	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).	Carotid-femoral pulse wave velocity
Height	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Weight	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Handgrip Strength	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Total cholesterol	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
High density lipoprotein	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Low Density Lipoprotein	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Triglycerides	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Apolipoprotein B	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Blood glucose	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).	Fasting blood glucose
Serum calcium	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Serum Potassium	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Serum bicarbonate	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Subjective global assessment	13 Weeks (collections in week 2, 5, 10, 13 which corresponds to before and during the last week of each of the three-week controlled diet periods).	Scored on a scale from 1-7 (severely malnourished to well nourished)
Albumin to creatinine ratio	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Blood urea nitrogen	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Creatinine	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Serum Phosphate	13 Weeks (collections in week 1, 2, 4, 5, 9, 10, 12, 13 which corresponds to before and during the last two weeks of each of the three-week controlled diet periods).
Urinary phosphorus excretion	13 Weeks (collections in week 2, 5, 10, 13 which corresponds to before and after each of the three-week controlled diet periods).	From 24-hour urine collection

Trial Locations

Locations (1)

Purdue University; 🇺🇸 West Lafayette, Indiana, United States