What is the evidence linking a low protein diet with delayed progression of Chronic Kidney Disease (CKD)?

From the Guidelines

Maintaining a protein intake of 0.8 g/kg body weight/d in adults with CKD G3–G5 is suggested, as it may help delay the progression of chronic kidney disease (CKD). This recommendation is based on the most recent and highest quality study available, which was published in 2024 1. The study suggests that avoiding high protein intake (>1.3 g/kg body weight/d) in adults with CKD at risk of progression is also beneficial.

Key Considerations

• In adults with CKD who are willing and able, and who are at risk of kidney failure, considering prescribing, under close supervision, a very low–protein diet (0.3–0.4 g/kg body weight/d) supplemented with essential amino acids or ketoacid analogs (up to 0.6 g/kg body weight/d) may be beneficial, as suggested by the 2024 KDIGO clinical practice guideline 1.
• It is essential to avoid prescribing low- or very low–protein diets in metabolically unstable people with CKD, as this may lead to malnutrition and other complications.
• The mechanism of reducing hyperfiltration and intraglomerular pressure, which decreases the workload on remaining functional nephrons, is thought to be responsible for the benefits of a low protein diet in patients with CKD, as supported by earlier studies 1.

Implementation

• Patients should work with a renal dietitian to ensure adequate caloric intake (30-35 kcal/kg/day) while restricting protein, focusing on high biological value proteins (eggs, fish, poultry) to maintain essential amino acid intake.
• Monitoring nutritional status is crucial, as malnutrition is a risk with overly restrictive diets.
• This approach is most beneficial for patients with stages 3-4 CKD (GFR 15-59 ml/min/1.73m²) and should be implemented under medical supervision with regular monitoring of kidney function and nutritional parameters, as recommended by the 2020 KDIGO clinical practice guideline 1.

From the Research

Evidence Linking Low Protein Diet with Delayed Progression of CKD

• A low-protein diet (LPD) is recommended for patients with non-dialysis advanced chronic kidney disease (CKD) to delay renal function decline 2.
• Studies have shown that LPD can help maintain nutritional status in patients with advanced CKD 2, and may be associated with slower progression of CKD 3.
• A systematic review and meta-analysis of controlled trials found that LPD was associated with higher serum bicarbonate levels, lower phosphorus levels, lower azotemia, and lower rates of progression to end-stage renal disease 3.
• Another study found that a very low-protein diet may reduce the number of people with CKD who progress to end-stage kidney disease (ESKD) 4.

Key Findings

• LPD can help maintain nutritional status in patients with advanced CKD, including serum albumin, nutritional status, and quality of life 2.
• LPD may be associated with slower progression of CKD, including lower rates of progression to ESKD 3.
• Very low-protein diets may reduce the number of people with CKD who progress to ESKD 4.
• LPD may not influence death, but may make little or no difference in the number of participants who reach ESKD compared with a normal protein diet 4.

Study Limitations

• Many studies had high risk of bias, including performance bias and detection bias 4.
• There were limited data on adverse effects, such as weight differences and protein energy wasting 4.
• Quality of life was not formally assessed in any studies 4.