Effects of Minimally vs. Ultra-Processed Diets on Potassium (K) Handling in CKD

NCT06920914 | Not Yet Recruiting DMC

• 2 other identifiers: Pro00139586RES0062629
• Study Type: interventional
• Target: 48
• Locations: 0 countries
• Sites: N/A

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.

Conditions

Chronic Kidney Disease

Keywords

CKD; Chronic Kidney Disease; potassium; hyperkalemia; hyperkalaemia; minimally processed foods; ultra-processed foods; feeding trial

Outcome Measures

Primary Outcomes (1)

• Fasting Serum Potassium Levels (mmol/L)

  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.

  Days 10, 36, 62, and 88.

Secondary Outcomes (6)

• Postprandial Whole-Blood Potassium Response (mmol/L)

  15, 30, 60, 90, 120, 150, 180 minutes post-meal at days 10, 36, 62, and 88.

• Potassium Bioavailability

  Days 7-9, 33-35, 59-61, 85-87.

• Body Composition (kg)

  Baseline and days 10, 36, 62, and 88.

• Body water (L)

  Baseline and days 10, 36, 62, and 88.

• 24h blood pressure (mmHg)

  Days 8-10, 34-36, 60-62, and 86-88.

Other Outcomes (4)

• Hyperkalemic Events

  Enrollment (Screening), baseline, and days 10, 36, 62, and 88.

• Potassium Content in Foods (mg)

  Before enrollment and through study completion, an average of 3 years

• Phosphorus Content in Foods (mg)

  Before enrollment and through study completion, an average of 3 years

Study Arms (4)

Low-potassium, ultra-processed diet

EXPERIMENTAL

Participants in this group will follow a diet consisting of ultra-processed foods with restricted potassium content.

Other: Low-potassium, ultra-processed diet

Normal potassium-rich, minimally processed diet

EXPERIMENTAL

Participants in this group will follow a diet consisting of minimally processed foods with a normal potassium content.

Other: Normal potassium-rich, minimally processed diet

Normal potassium-rich, ultra-processed diet

EXPERIMENTAL

Participants in this group will follow a diet consisting of ultra-processed foods with a normal potassium content.

Other: Normal potassium-rich, ultra-processed diet

Low-potassium, minimally processed diet

EXPERIMENTAL

Participants in this group will follow a diet consisting of minimally processed foods with restricted potassium content.

Other: Low-potassium, minimally processed diet

Interventions

Low-potassium, minimally processed diet OTHER

A diet restricted in naturally occurring potassium, primarily composed of fresh fruits, vegetables, whole grains, and other minimally processed foods.

Low-potassium, minimally processed diet

Normal potassium-rich, ultra-processed diet OTHER

A diet with normal potassium content, primarily composed of industrially processed foods such as packaged snacks and processed meals

Normal potassium-rich, ultra-processed diet

Low-potassium, ultra-processed diet OTHER

A diet restricted in potassium, primarily composed of industrially processed foods such as packaged snacks and processed meals.

Low-potassium, ultra-processed diet

Normal potassium-rich, minimally processed diet OTHER

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.

Normal potassium-rich, minimally processed diet

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.
• 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.

Sponsors & Collaborators

• University of Alberta: lead
• Canadian Institutes of Health Research (CIHR): collaborator

Related Publications (7)

• Picard K, Barreto Silva MI, Mager D, Richard C. Dietary Potassium Intake and Risk of Chronic Kidney Disease Progression in Predialysis Patients with Chronic Kidney Disease: A Systematic Review. Adv Nutr. 2020 Jul 1;11(4):1002-1015. doi: 10.1093/advances/nmaa027.

  PMID: 32191264 BACKGROUND

• Picard K, Mager DR, Senior PA, Richard C. Potassium-Based Sodium Substitutes Impact the Sodium and Potassium Content of Foods. J Ren Nutr. 2025 Jan;35(1):64-71. doi: 10.1053/j.jrn.2024.05.010. Epub 2024 Jun 6.

  PMID: 38848804 BACKGROUND

• Picard K. Potassium Additives and Bioavailability: Are We Missing Something in Hyperkalemia Management? J Ren Nutr. 2019 Jul;29(4):350-353. doi: 10.1053/j.jrn.2018.10.003. Epub 2018 Dec 19.

  PMID: 30579674 BACKGROUND

• Picard K, Picard C, Mager DR, Richard C. Potassium content of the American food supply and implications for the management of hyperkalemia in dialysis: An analysis of the Branded Product Database. Semin Dial. 2024 Jul-Aug;37(4):307-316. doi: 10.1111/sdi.13007. Epub 2021 Jul 29.

  PMID: 34323307 BACKGROUND

• Picard K RD BSc, Senior PA MBBS PhD FRCP(E) FRCP, Wilmott A BSc, Jindal K MD FRCPC, Richard C RD PhD, Mager DR RD PhD. Comparison of diet quality tools to assess nutritional adequacy for adults living with kidney disease. Can J Diet Pract Res. 2022 Dec 1;83(4):180-185. doi: 10.3148/cjdpr-2022-009. Epub 2022 May 3.

  PMID: 35503893 BACKGROUND

• Picard K, Senior PA, Adame Perez S, Jindal K, Richard C, Mager DR. Low Mediterranean Diet scores are associated with reduced kidney function and health related quality of life but not other markers of cardiovascular risk in adults with diabetes and chronic kidney disease. Nutr Metab Cardiovasc Dis. 2021 May 6;31(5):1445-1453. doi: 10.1016/j.numecd.2021.02.002. Epub 2021 Feb 11.

  PMID: 33812736 BACKGROUND

• Picard K, Griffiths M, Mager DR, Richard C. Handouts for Low-Potassium Diets Disproportionately Restrict Fruits and Vegetables. J Ren Nutr. 2021 Mar;31(2):210-214. doi: 10.1053/j.jrn.2020.07.001. Epub 2020 Aug 20.

  PMID: 32830022 BACKGROUND

MeSH Terms

Conditions

Renal Insufficiency, Chronic; Hyperkalemia

Condition Hierarchy (Ancestors)

Renal Insufficiency; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases; Chronic Disease; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Water-Electrolyte Imbalance; Metabolic Diseases; Nutritional and Metabolic Diseases

Study Officials

• Caroline Richard, PhD

  University of Alberta

  PRINCIPAL INVESTIGATOR

• Branko Braam, MD, PhD

  University of Alberta

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Jenneffer Rayane Braga Tibaes, PhD

CONTACT

7804929506; bragatib@ualberta.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 10, 2024
• First Posted: April 10, 2025
• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): June 1, 2028
• Last Updated: February 5, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share