Safety of a Healthy Plant-based Diet With Higher Potassium Content, Compared to a Healthy Plant-based Diet With Limited Potassium Content in Patients With Chronic Kidney Disease: A Pilot Study

NCT07494266 | Not Yet Recruiting

• 1 other identifier: 2025-06661-01
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

For many years, people with moderate to advanced chronic kidney disease (CKD) have been advised to limit their intake of potassium, a mineral found in many foods such as fruit, vegetables, legumes, whole grains, and nuts. The reason for this has been the risk of hyperkalemia, a condition in which the potassium level in the blood becomes too high and can be dangerous. In recent years, however, this view has been questioned. New research suggests that the link between potassium in food and high potassium levels in the blood may not be as clear as previously thought. People who follow a strict potassium-restricted diet experience a lower quality of life and less satisfaction with their dietary treatment. At the same time, they miss out on the health benefits of eating a varied and nutritious diet. Today, many experts advocate a more individualized approach to potassium intake: instead of generally restricting potassium, the goal should be to maintain normal potassium levels in the blood, while encouraging a healthy diet. However, this message is not always clear in healthcare, and many people therefore continue to avoid potassium-rich foods altogether. The result is that they eat fewer natural ingredients and instead consume more processed and ultra-processed foods. Such foods can be more harmful, partly because they often contain potassium additives that are absorbed effectively by the body and their quantities are not reported in the nutritional label. This "hidden" potassium can contribute more to high potassium levels in the blood than the potassium that occurs naturally in plant-based foods. In addition, potassium from whole plant-based foods is absorbed more slowly, partly due to its fiber content. Plant-based diets may also have other positive effects for people with kidney disease: they can contribute to reduced blood acidity, known as metabolic acidosis, healthier gut flora, lower levels of inflammation, and reduced phosphorus intake. Together, these factors can counteract several of the metabolic complications associated with kidney disease. In a previous study, our research group showed that even patients with advanced kidney disease (CKD stage 4-5) and already elevated potassium levels could follow a healthy plant-based diet if they also used a potassium-binding drug (sodium zirconium cyclosilicate, SZC). This enabled them to eat more fruit, vegetables, and legumes, while also experiencing improved quality of life. The current study builds on these results and is planned as a pilot study in which patients with moderate to advanced kidney disease, but who are not yet being treated with dialysis, are assigned to two different dietary strategies for six months:

• Healthy plant-based diet (healthy-PBD): a more liberal and balanced plant-based diet without specific potassium restrictions.
• Potassium-restricted plant-based diet (restricted-PBD): a traditional plant-based diet with restrictions on potassium-rich foods, according to current standard recommendations. The main purpose is to investigate whether the healthy plant-based diet leads to more or more severe cases of hyperkalemia than the restricted diet. Our hypothesis is that potassium levels may increase slightly in the group with a liberal diet, but not to dangerous levels. The study will also examine secondary outcomes, such as quality of life, satisfaction with treatment, and how well patients accept the diet. In addition, taste experiences will be tested with taste strips (sweet, sour, salt, bitter and umami) before and after the intervention in both groups. If this pilot study shows that a healthier and less restrictive diet is safe, it could pave the way for a larger study investigating the long-term metabolic effects of a plant-based diet in kidney care.

Conditions

Hyperkalemia; Chronic Kidney Disease (Stages 4 and 5)

Keywords

Chronic kidney disease; Hyperkalemia; Plant-based diet; Potassium; Patient satisfaction with CKD treatment; RCT; Pilot study

Outcome Measures

Primary Outcomes (1)

• Number of hyperkalemia (plasma potassium >5.5 mmol/L) events in the two groups

  Hyperkalemia is defined as plasma potassium \> 5.5 mmol/L. The number of hyperkalemia events, as well as the time to the event, will be registered.

  for 26 weeks following randomization

Secondary Outcomes (25)

• Quality of life (RAND-36 questionnaire - score 0 to 100)

  for 26 weeks following randomization

• Renal Treatment Satisfaction Questionnaire - score 0 to 6

  for 26 weeks following randomization

• C-reactive protein (mg/L)

  for 26 weeks following randomization

• Interleukin 6 (pg/mL)

  for 26 weeks following randomization

• Glomerular filtration rate (ml/min/1.73 m2)

  for 26 weeks following randomization

Study Arms (2)

Healthy plant-based diet (healthy-PBD)

EXPERIMENTAL

Other: Healthy plant-based diet (healthy-PBD)

Potassium-restricted plant-based diet (restricted-PBD)

ACTIVE COMPARATOR

Other: Potassium-restricted plant-based diet

Interventions

Healthy plant-based diet (healthy-PBD) OTHER

Healthy plant-based diet (healthy-PBD): A liberal plant-based diet that includes fruits, vegetables, legumes, whole grains, and nuts, with no specific restrictions on potassium.

Healthy plant-based diet (healthy-PBD)

Potassium-restricted plant-based diet OTHER

Potassium-restricted plant-based diet (restricted-PBD): A plant-based diet with restrictions on potassium-rich foods, which corresponds to current standard advice for patients with CKD.

Potassium-restricted plant-based diet (restricted-PBD)

Eligibility Criteria

• Age: 20 Years - 85 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age between 20 and 85 years
• Chronic kidney disease (CKD) with an estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73 m²
• Normal potassium levels (plasma potassium 3.5-5.3 mmol/L)
• Not on dialysis
• Good knowledge of Swedish

You may not qualify if:

• Pregnancy
• Breastfeeding
• Kidney transplant
• Regular use of potassium binders at least 4 days/week (e.g. sodium zirconium cyclosilicate, patiromer or sodium polystyrene sulfonate)
• Regular prescription of daily potassium salts (e.g. potassium chloride)
• Planned kidney transplant
• Planned start of dialysis within the next 6 months
• Allergy to nuts (including peanuts)
• Mental illness and cognitive impairment that impede understanding of dietary advice
• Comorbidities that may affect potassium balance (e.g. adrenal insufficiency, inflammatory bowel disease, chronic diarrhoea or colostomy)

Sponsors & Collaborators

• Karolinska Institutet: lead

Study Sites (1)

Karolinska Institute

Huddinge, Stockholm Län, 14152, Sweden

Location

Related Publications (20)

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MeSH Terms

Conditions

Hyperkalemia; Renal Insufficiency, Chronic

Condition Hierarchy (Ancestors)

Water-Electrolyte Imbalance; Metabolic Diseases; Nutritional and Metabolic Diseases; 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

Central Study Contacts

Carla M Avesani, RD, PhD, Associate Professor

CONTACT

+46 725460974; carla.avesani@ki.se

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: RD, PhD, Associate Professor in Nutrition, Senior Research Specialist

Study Record Dates

• First Submitted: March 9, 2026
• First Posted: March 27, 2026
• Study Start: April 10, 2026
• Primary Completion (Estimated): December 30, 2029
• Study Completion (Estimated): June 30, 2030
• Last Updated: April 29, 2026

Record last verified: 2026-04

Locations

SE (1)