Low-Protein Diet May Slow CKD Progression and Improve Outcomes: JAMA

The perspective article, authored by Denise Mafra from the Graduate Program in Biological Sciences–Physiology at the Federal University of Rio de Janeiro (UFRJ), Brazil, and colleagues, examines the current evidence, ongoing debates, and practical considerations surrounding low-protein diets (LPDs) in patients with impaired kidney function.

While LPDs have long been recommended in CKD care, their overall benefits remain a subject of discussion due to the complexity of dietary research and the challenges in accurately assessing long-term nutritional intake.

The authors explain that studying diet-related interventions is inherently difficult, as results may be influenced by recall bias, adherence issues, and variability in patient behavior. These limitations have contributed to inconsistent findings across studies and ongoing controversy about the extent to which protein restriction can slow CKD progression. Despite these challenges, a substantial body of literature links excessive protein intake in CKD patients to multiple adverse outcomes.

High protein consumption has been associated with increased cardiovascular risk, oxidative stress, inflammation, hyperphosphatemia, bone mineral disorders, metabolic acidosis, and disturbances in gut microbiota. Together, these factors not only accelerate kidney damage but also contribute to systemic complications that further worsen patient outcomes. The accumulation of nitrogenous waste products resulting from high protein intake places additional strain on already compromised kidneys, reinforcing the rationale for moderation.

At the same time, the authors caution against overly aggressive protein restriction. Insufficient protein intake may lead to loss of muscle mass, poor nutritional status, and increased vulnerability to illness, potentially negating the benefits of dietary intervention. This dual risk underscores the importance of tailoring protein intake to individual patient needs rather than applying a uniform dietary prescription.

According to the review, LPDs can be a valuable approach for non-dialysis CKD patients when factors such as age, stage of disease, nutritional status, and associated complications are carefully evaluated. Patients with stable metabolic profiles may benefit most from controlled protein intake, provided that energy requirements are adequately met and dietary plans are closely monitored. In contrast, individuals with conditions such as cachexia, active inflammation, catabolic illnesses, or difficulty maintaining sufficient caloric intake may require more flexible protein targets to avoid malnutrition.

In their concluding remarks, the authors note that while consensus is lacking on whether LPDs definitively delay CKD progression, their favorable effects on phosphate balance, cardiovascular health, intestinal dysbiosis, and metabolic acidosis are well recognized. Thoughtfully planned dietary care in CKD stages 3 to 5 can improve nutritional status, reduce metabolic disturbances, decrease reliance on medications, and potentially postpone the initiation of dialysis.

Overall, the review supports LPDs as a safe and beneficial strategy for metabolically stable, non-dialysis CKD patients, emphasizing that success depends on individualized planning, regular monitoring, and integration into comprehensive kidney care.

Reference:

Mafra, D., Brum, I., Borges, N. A., Leal, V. O., & Fouque, D. (2025). Low-protein diet for chronic kidney disease: Evidence, controversies, and practical guidelines. Journal of Internal Medicine, 298(4), 319-335. https://doi.org/10.1111/joim.20117