The Obsession with High Dietary Protein Intake in ESRD Patients on Dialysis: Is It Justified?

Abstract

Background: The belief that dialysis patients require a much higher intake of protein than the average person is widely held among nephrologists and a recent editorial review on the care of patients undergoing hemodialysis advised a protein intake of at least 1.5 g/kg/day in this population. In theory, the requirements for daily protein intake of dialysis patients should be the same as normals plus whatever extra obligatory nitrogen losses are imposed by the dialytic process. Since the average loss of protein and/or amino acids is about 8 g/day in peritoneal dialysis and 8 g per session in hemodialysis patients, the daily intake of protein in dialysis patients needs to be increased only by this small magnitude. Methods: All the literature reporting on nitrogen balance data on different protein intakes in chronic maintenance dialysis patients was reviewed and analyzed. Results: There were 3 balance studies adressing this issue in hemodialysis patients and 6 in peritoneal dialysis patients. These data show that dialysis patients are in nitrogen balance even with a protein intake as low as 0.7 g/kg/day. Conclusions: The nitrogen balance data confirm that in stable dialysis patients a safe requirement of protein intake is about 1 g/kg/day and attempts at increasing protein intake beyond this value are not warranted. The persistent recommendation of a high dietary intake of protein for dialysis patients may reflect the influence of two other issues: the belief that dialysis is a catabolic event, and the data showing an inverse correlation between protein intake and outcome.