Chronic Kidney Disease
Conditions
Keywords
CKD, Chronic Kidney Disease, potassium, hyperkalemia, hyperkalaemia, minimally processed foods, ultra-processed foods, feeding trial
Brief summary
What is this study about? This clinical trial is designed to learn how potassium from different types of food affects blood potassium levels and overall health in people with chronic kidney disease (CKD, stages 3B-5). People with CKD are often advised to avoid potassium-rich foods, even though fresh fruits and vegetables are important for good health. However, potassium in processed foods (such as packaged snacks and ready-made meals) may be absorbed differently than potassium from fresh foods. This study will compare minimally processed vs. ultra-processed foods to determine how different sources of potassium affect potassium levels and help create better dietary recommendations for people with CKD. What are the study goals? The study will answer: * Does potassium from fresh foods (like fruits and vegetables) affect blood potassium differently than potassium from processed foods? * How does dietary potassium impact potassium absorption and excretion in people with CKD? Researchers will compare the effects of four diets to understand how low and normal-potassium rich diets from fresh vs. processed foods influence: * Blood potassium levels * Body composition (muscle, fat, and fluid balance) * Vascular health What will participants do? Participants will follow four different 10-day diets over the course of the study. All food will be provided at no cost. These diets are: * Minimally processed with low-potassium content * Minimally processed with normal potassium content * Ultra-processed with with low-potassium content * Ultra-processed with normal potassium content There will be 16-day breaks (washout period) between diets where participants return to their normal eating habits. During the study, participants will: * Pick up prepared meals from the research center approximately 3 times per week. * Attend checkups for weight, blood pressure, and blood tests. * Provide urine samples to track potassium levels. * Wear a comfortable, cuff-free blood pressure monitor at home. * Keep a study journal to track diet, medications, and symptoms. * Complete questionnaires about diet satisfaction and health changes.
Interventions
OTHERLow-potassium, ultra-processed diet
A diet restricted in potassium, primarily composed of industrially processed foods such as packaged snacks and processed meals.
OTHERLow-potassium, minimally processed diet
A diet restricted in naturally occurring potassium, primarily composed of fresh fruits, vegetables, whole grains, and other minimally processed foods.
OTHERNormal potassium-rich, minimally processed diet
A diet with normal potassium content, primarily composed of fresh fruits, vegetables, whole grains, and other minimally processed foods, rich in naturally occurring potassium, following a Mediterranean-style pattern.
OTHERNormal potassium-rich, ultra-processed diet
A diet with normal potassium content, primarily composed of industrially processed foods such as packaged snacks and processed meals
Sponsors
University of Alberta
Canadian Institutes of Health Research (CIHR)
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Participants aged ≥18 years living with stage 3B-5 CKD (estimated glomerular filtration rate ≥ 15 mL/min/1.73m2) on conservative kidney management (not on dialysis). * Able and willing to follow a controlled feeding regimen, attend in-person visits, provide informed consent, and comply with study procedures.
Exclusion criteria
General * Pregnant or lactating women. * Transitioning transgender individuals. * Individuals with strict dietary preferences (e.g., vegetarians, vegans) or allergies/intolerance that would preclude participation in the diet phases. Kidney Function * Foreseen start of renal replacement therapy within the next 6 months. * Acute kidney injury in the past 3 months. * 2-year Kidney Failure Risk Equation \> 40%. * Preemptive kidney transplant planned within the next 6 months. * History of kidney transplant. * Active glomerulonephritis. Comorbidities * Acute myocardial infarction or stroke within the past 6 months. * Active cancer. * Ileostomy, short bowel syndrome or inflammatory bowel disease. * Body mass index \< 18.5 or ≥ 35. * New York Heart Association Class III or IV congestive heart failure. * History of ventricular arrhythmia. * Major surgery within the past 3 months. * Active autoimmune disease. * Glycated hemoglobin \> 10% within the past 3 months. * Gastroparesis. * Chronic nausea and vomiting. * Intensive care unit admission within the past 3 months. * Significant psychiatric disease. * Uncontrolled blood pressure (above 160/100). Current Use of Medications/Supplements * Immunosuppressives. * Potassium binders. * Lithium. * Motility agents. * More than 2 medications that inhibit renal potassium excretion (e.g., angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, mineralocorticoid receptor antagonists). * Supplements known to influence potassium levels. Potassium-Related Conditions * Potassium \> 5.5 mmol/L in more than 3 episodes within the past year. * Participants with genetic issues affecting potassium handling (e.g. Barter and Liddle syndrome) or other unique health conditions that could interfere with potassium handling. Intervention-related Conditions * Fluid volume status or hypertension being actively managed. Other Factors * Documented non-adherence to medications or other therapeutic measures. * Use of tube feeding or parenteral nutrition.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Fasting Serum Potassium Levels (mmol/L) | Days 10, 36, 62, and 88. | This measure assesses the concentration of potassium in participants' blood after fasting overnight. Normal potassium levels typically range from 3.5 to 5.0 mmol/L. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Postprandial Whole-Blood Potassium Response (mmol/L) | 15, 30, 60, 90, 120, 150, 180 minutes post-meal at days 10, 36, 62, and 88. | This measure examines changes in blood potassium levels after a standardized test meal. Blood samples are collected before the meal (baseline) and at regular intervals (15, 30, 60, 90, 120, 150, and 180 minutes) to calculate the area under the curve (AUC), which reflects the total potassium response over time. |
| Dietary Satisfaction Questionnaire | Days 10, 36, 62, and 88. | Self-administered questionnaire to provide feedback on the palatability, variety, and overall acceptability of the study-provided diets. |
| Body Composition (kg) | Baseline and days 10, 36, 62, and 88. | This measure estimates participants' fat mass and fat-free mass. Body composition is assessed using bioelectrical impedance analysis, which uses safe, low-level electrical currents to estimate tissue and fluid distribution. Results are reported in kilograms (kg). |
| Body water (L) | Baseline and days 10, 36, 62, and 88. | This measure evaluates fluid status, i which plays a role in potassium handling. Body water is estimated using bioelectrical impedance analysis, which uses safe, low-level electrical currents to estimate tissue and fluid distribution. Results are reported in liters for total, extracellular, and intracellular water. |
| 24h blood pressure (mmHg) | Days 8-10, 34-36, 60-62, and 86-88. | Systolic and diastolic blood pressure will be monitored for 24h. |
| Potassium Bioavailability | Days 7-9, 33-35, 59-61, 85-87. | Potassium bioavailability is assessed by measuring the potassium content in 24-hour urine samples. This provides insights into how much potassium from the diet is absorbed and how much is excreted by the body. |
Contacts
CONTACTJenneffer Rayane Braga Tibaes, PhD
PRINCIPAL_INVESTIGATORCaroline Richard, PhD
University of Alberta
PRINCIPAL_INVESTIGATORBranko Braam, MD, PhD
University of Alberta
Outcome results
None listed