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

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

Interventions

OTHER

Low-potassium, ultra-processed diet

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

OTHER

Low-potassium, minimally processed diet

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

OTHER

Normal 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.

OTHER

Normal 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 & Collaborators

• Canadian Institutes of Health Research (CIHR)

  collaborator OTHER_GOV

• University of Alberta

  lead OTHER

Principal Investigators

• Caroline Richard, PhD · University of Alberta

• Branko Braam, MD, PhD · University of Alberta

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-07-01

Primary Completion

2027-12-01

Completion

2028-06-01