Renal Nutrition Update

Potassium management is a key part of nephrology care and is generally carefully monitored given the risk of cardiac arrhythmias that can occur with potassium imbalance. This fear tends to make potassium restriction a hallmark for the renal diet and is often the first diet recommendation for those with chronic kidney disease (CKD). More recent evidence, however, challenges this restriction with a call for more individualized and liberal recommendations.

In 2020, the KDOQI (Kidney Disease Outcomes Quality Initiative) guidelines released updated guidance on potassium management with the following recommendations:1

• It is reasonable to adjust dietary intake to maintain serum potassium within the normal range.

• In adults with hyper- or hypokalemia, we suggest dietary or supplemental potassium intake be based on a patient’s individual needs and clinician judgment.

These guidelines shift our potassium recommendations from “everyone with CKD needs a potassium restriction” to basing potassium recommendations on a patient’s individual needs and serum fixed, clinicians should consider looking at potassium as a red flag that something upstream might need to be addressed. Multiple studies indicate benefits for a more liberal potassium diet in those with CKD, including improved blood pressure and lower risk for stroke, arrhythmia, myocardial infarction, and death related to cardiovascular events.2 This is an important consideration given that adverse cardiovascular difficulties related to following the renal diet are that its recommendations are complex and it contradicts a healthy eating pattern, conflicts with other dietary recommendations for disease (such as for improving heart health), fails to achieve desired results despite adhering to recommendations, and alienates patients from others at cultural or social events or even their own family due to having to make separate meals. A more liberalized diet can improve the nutrition quality of life for CKD patients and may increase adherence to other recommendations.6

—Mild to moderate CKD: 4.7g/day with normal serum potassium levels

—Advanced CKD: <3g/day if serum levels are elevated despite high fiber intake

—Dialysis < 3g/ day and encourage high fiber intake

3. Consider that most of the potassium in diets comes from intake of potatoes, savory snacks, fruit juice, coffee, tea, beer, animal protein, and dairy.8 Restricting fruits and vegetables is less likely to have a positive impact if potassium is high due to intake.

4. Clarify follow-up with patients and staff on lab redraws or follow-up visits so that potassium issues can be resolved in a timely manner.

5. If potassium is high (or low), refer out to a renal dietitian. Many of the root causes of high potassium can be resolved with a nutrition approach. Dietitians and other nephrology providers can work as a team to provide optimal support for CKD patients. ■

Lindsey Zirker, MS, RD, CSR is a renal dietitian who works with the Kidney Nutrition Institute in Titusville, Florida. She specializes in autoimmune kidney disease and advanced practice medical nutrition therapy for people with kidney disease.

References

levels and clinician judgment, which may prompt consideration of interventions other than dietary restriction to achieve normal serum levels when appropriate.

The rationale for this more individualized approach for potassium recommendations is meant to remind nephrology providers that the KDOQI workgroup found no clinical trials on how modifying diet can influence serum potassium levels in patients with CKD and that there are multiple factors for serum potassium changes.1 Instead of seeing high potassium as the problem that needs to be events are the current leading cause of death in those with CKD not on dialysis as well as on dialysis.3,4

Other benefits of a more liberal potassium diet are slower progression of CKD due to improved control of metabolic acidosis and reduced inflammation and fibrosis, 2 improved gut health and reduced production of uremic toxins,5 reduced age-related bone loss, and decreased risk of kidney stones.2

A survey of patients on dialysis found helpful insights into the patient perspective of the renal diet. Common

More liberal, individualized potassium recommendations can improve patient outcomes and quality of life. Some guidelines and tips for implementing these recommendations are as follows:

1. Consider these questions to help pinpoint the root issue of high potassium:

—Is this potassium level consistent with the current trend?

—Does this patient take medications that impact potassium (or had a recent medication dose change)?

—Has the patient been losing muscle mass or having a reduced appetite?

—What foods has the patient been eating recently?

2. Guidelines for potassium intake based on stage and serum level:7

1. Ikizler TA, Burrowes JD, Byham-Gray LD, et al. KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update. Am J Kidney Dis. 2020;76(3 Suppl 1):S1S107. doi:10.1053/j.ajkd.2020.05.006. Erratum in: Am J Kidney Dis. 2021 Feb;77(2):308.

2. Terker A, Saritas T, McDonough A. The highs and lows of potassium intake in chronic kidney disease Does one size fit all? J Am Soc Nephrol. 2022;33(9):16381640. doi:10.1681/ASN.2022070743.

3. National Institute of Health. Kidney disease statistics for the United States. https://www.niddk.nih.gov/ health-information/health-statistics/kidney-disease. Accessed 10/29/21.

4. Navaneethan SD, Schold JD, Arrigain S, Jolly SE, Nally JV Jr. Cause-specific deaths in non-dialysis-dependent CKD. J Am Soc Nephrol. 2015;26(10):2512-2520. doi:10.1681/ASN.2014101034

5. Lau WL, Kalantar-Zadeh K, Vaziri ND. The gut as a source of inflammation in chronic kidney disease. Nephron 2015;130(2):92-98. doi:10.1159/000381990.

6. Stevenson J, Tong A, Gutman T, et al. Experiences and perspectives of dietary management among patients on hemodialysis: An interview study. J Ren Nutr. 2018;28(6):411-421. doi:10.1053/j.jrn.2018.02.005. Epub 2018 Apr 22. PMID: 29691161.

7. Kalantar-Zadeh K, Fouque D. Nutritional management of chronic kidney disease. N Engl J Med. 2017;377(18): 1765-1776. doi:10.1056/NEJMra1700312.

8. Lanham-New SA, Lambert H, Frassetto L. Potassium. Adv Nutr. 2012;3(6):820-821.