Compares two plant-based diets with different potassium levels in chronic kidney disease

Trial details

Who runs it

Karolinska Institutet

Trial code

NCT07494266

Record updated

2 October 2026

Original description

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.Read full original descriptionShow less

Säkerheten av en hälsosam växtbaserad Kost Med högre kaliuminnerhåll, jämfört Med en hälsosam växtbaserad Kost Med begränsat kaliuminnehåll Hos Patienter Med Kronisk Njursjukdom: En Pilotstudie

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.

Inclusion: 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.

Exclusion: Kidney transplant; Planned kidney transplant; Allergy to nuts (including peanuts); Mental illness and cognitive impairment that impede understanding of dietary advice; 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); Comorbidities that may affect potassium balance (e.g. adrenal insufficiency, inflammatory bowel disease, chronic diarrhoea or colostomy); Pregnancy; Breastfeeding; Planned start of dialysis within the next 6 months.

ClinicalTrials.gov NCT07494266