Eduardo Lorca-Herrera, Sociedad Chilena de Nefrología, Providencia, Chile; Departamento de Medicina Interna Oriente, Facultad de Medicina, Universidad de Chile, Providencia, Chile
Verònica Soto, Servicio de Nefrología, Hospital del Salvador, Santiago, Chile
Macarena Arancibia, Centro de Nutrición CardioRenal, Santiago, Chile
Maria R. Berlanga, Departamento de Nutrición, Facultad de Medicina, Universidad del Desarrollo, Santiago, Chile
Francisca Peña, Departamento de Nutrición, Facultad de Medicina, Universidad San Sebastian, Santiago, Chile
Caterina Tiscornia, Departamento de Nutrición, Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
Magdalena Whittaker, Centro de Nutrición CardioRenal, Santiago, Chile
Gonzalo Correa, Servicio de Nefrología, Hospital del Salvador, Santiago, Chile
Jefferson Hidalgo, Servicio de Nefrología, Hospital del Salvador, Santiago, Chile
Alvaro Morales, Servicio de Nefrología, Hospital del Salvador, Santiago, Chile
Alvaro Rios, Servicio de Nefrología, Hospital del Salvador, Santiago, Chile
Daniel Bunout, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile. Santiago, Chile

Objective: To assess the effects of a very low protein diet supplemented with ketoacids on urinary urea nitrogen excretion and kidney function tests, in a randomized controlled clinical trial. Material and methods: Patients with stage 4-5 of CKD treated at a nephrology unit of a general hospital, were randomized to receive Ketosteril® 1 tablet per 5 kg/body weight day and a very low protein diet providing 0.3 g/kg of proteins or only a low protein diet providing 0.6 g/kg of proteins (control group). At baseline and after 16 weeks of treatment, fasting blood, 24 h and spot urine samples were collected. Results: Eighty-nine patients were randomized to the control and 93 to the ketoacids group. Fifty-four and 71 patients in each group, respectively, completed the treatment. Patients in the ketoacids group experienced a significantly higher reduction in urinary urea nitrogen and urine phosphorus excretion. Specifically, serum creatinine and cystatin C, did not change significantly. Conclusions: Patients receiving ketoacids had a greater reduction in urine urea nitrogen excretion during the treatment period which reflects good compliance with the very low protein diet.

Keywords: Renal failure. Ketoacids. Dietary proteins.