A healthy intake in of potassium is recommended by health authorities to reduce blood pressure and the risk of cardiovascular damage, stroke and coronary heart disease. However, in patients with advanced chronic kidney disease (CKD) and those with end stage renal disease (ESRD), potassium intake must be limited to prevent hyperkalaemia.
The main challenge of dietary potassium management in such patients is to maintain a high fibre intake and a low net fixed-acid load, said the authors, a team from the University of Pisa, Italy, the University of Tennessee and the University of California Irvine (UCI).
As metabolic acidosis, cardiovascular disease and constipation are common comorbidities in advanced CKD patients, it is desirable to include in their diet heart-healthy nutrients with high fibre, high anti-oxidant vitamins and high alkali content such as fresh fruits and vegetables. However, such foods are potassium-rich, posing a risk of hyperkalaemia, explained the authors.
“To achieve a careful reduction of dietary potassium load without a decrease in alkali or fibre intake, we recommend the implementation of certain pragmatic dietary interventions as follows,” said lead author Professor Adamasco Cupisti, from the University of Pisa.
- “Improving knowledge and education about the type of foods with excess potassium (per serving or per unit of weight);
- Identifying foods that are needed for healthy nutrition in renal patients; classification of foods based on their potassium content normalized per unit of dietary fibre;
- Education about the use of cooking procedures (such as boiling) in order to achieve effective potassium reduction before eating;
- Attention to hidden sources of potassium, in particular additives in preserved foods and low-sodium salt substitutes.”
Within this framework, Cupisti encouraged favouring foods that have low potassium to fibre and protein ratio, and avoiding high potassium foods.
“Using these principles, a pragmatic educational tool can be prepared to make the implementation of diets with limited potassium content and more patient-friendly in the management for CKD and ESRD patients with chronic or recurrent hyperkalaemia.”
Target potassium intakes
In healthy adults, the US Food and Nutrition Board of the Institute of Medicine has set an adequate intake for potassium of 4.7 grams/day (g/d), while the World Health Organization (WHO) recommends 3.9 g/d. These levels of intake are also generally acceptable in patients with mild-moderate CKD and low proteinuria, explained co- author Professor Kamyar Kalantar-Zadeh from UCI. However, lower intakes may also be necessary if patients are received angiotensin-converting enzyme (ACE) inhibitors or other potassium sparing medications.
In patients with advanced CKD, ESRD or undergoing regular haemodialysis, potassium intake should be restricted to less than 3 g/d, the researchers emphasised.
Hyperkalaemia is generally recognised as a serum potassium level above 5.3 milliEquivalents per litre (mEq/L).
Volume 10, issue 2, article 261, doi: 10.3390/nu10030261
“Dietary Approach to Recurrent or Chronic Hyperkalaemia in Patients with Decreased Kidney Function”
Authors: Adamasco Cupisti, Csaba P. Kovesdy, Claudia D’Alessandro and Kamyar Kalantar-Zadeh