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.
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 Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
15
Participants will complete a 2-week baseline period consuming their standard diet without any food or beverages provided followed by a randomized, crossover-controlled feeding study of a lacto-ovo vegetarian diet versus the same diet with 20% of the protein replaced by red meat. In between the two diets, there will be a five-week washout where participants will consume their standard diet without any food or beverages provided.
Purdue University
West Lafayette, Indiana, United States
Serum trimethylamine N-oxide
Intra- and interparticipant variability of serum concentrations as measured by high performance liquid chromatography-mass spectrometry
Time frame: 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).
Additional serum uremic toxins
Including p-cresyl sulfate and indoxyl sulfate measured by high performance liquid chromatography-mass spectrometry
Time frame: 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 excretion of uremic toxins
Measured by a ratio of serum and urine values
Time frame: 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).
Gut microbiota
Diversity and composition of the gut microbiome
Time frame: 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).
Gastrointestinal symptoms
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.
Time frame: 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).
Stool consistency
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Measured on a scale from 1 to 7 using the Bristol Stool Scale/Chart.
Time frame: 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 pressure
Time frame: 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
Carotid-femoral pulse wave velocity
Time frame: 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).
Height
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Fasting blood glucose
Time frame: 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 calcium
Time frame: 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
Time frame: 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
Time frame: 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
Scored on a scale from 1-7 (severely malnourished to well nourished)
Time frame: 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).
Albumin to creatinine ratio
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
From 24-hour urine collection
Time frame: 13 Weeks (collections in week 2, 5, 10, 13 which corresponds to before and after each of the three-week controlled diet periods).