Short-term effects of a very-low-protein diet supplemented with ketoacids in nondialyzed chronic kidney disease patients

Objective: To evaluate the effects on the nutritional and metabolic parameters of a very-low-protein diet supplemented with ketoacids (VLPD+KA) in comparison with a conventional low-protein diet (LPD) in chronic kidney disease (CKD) patients.Design: Prospective, randomized, controlled clinical study.Setting: Outpatient Clinic of the Nephrology Division of Federal University of São Paulo, Brazil.Subjects: the study involved 24 patients with advanced CKD ( creatinine clearance <25 ml/min) that were randomly assigned to either a VLPD+KA (VLPD+KA group, 12 patients) or to a conventional LPD with 0.6 g/kg/day ( LPD group, 12 patients). the patients were followed for 4 months.Results: Nutritional status was adequately maintained with both diets for the studied period. Protein intake and serum urea nitrogen decreased significantly only in the VLPD+KA group ( from 0.68 +/- 0.17 to 0.43 +/- 0.12 g/kg/day, P<0.05; from 61.4 +/- 12.8 to 43.6 +/- 14.9 mg/dl, P<0.001; respectively). Ionized calcium did not change in the VLPD+KA group but tended to decrease in the LPD group. Serum phosphorus tended to decrease in the VLPD+KA group probably as a result of a significant reduction in dietary phosphorus (529 +/- 109 to 373 +/- 125 mg/day, P<0.05) associated to the phosphorus-binding effect of the ketoacids. No change in these parameters was found in the LPD group. Serum parathormone increased significantly only in the LPD group (from 241 +/- 138 to 494 +/- 390 pg/ ml, P<0.01). the change in PTH concentration was negatively correlated with changes in ionized calcium concentration ( r = - 0.75, P = 0.02) and positively correlated with changes in serum phosphorus ( r = 0.71, P = 0.03) only in the LPD group.Conclusion: This study indicates that a VLPD+KA can maintain the nutritional status of the patients similarly to a conventional LPD. Besides, an improvement in calcium and phosphorus metabolism and a reduction in serum urea nitrogen were attained only with the VLPD+KA. Thus, VLPD+KA can constitute another efficient therapeutic alternative in the treatment of CKD patients.Sponsorship: This study was supported by CAPES, Oswaldo Ramos Foundation and Fresenius Kabi, Ltda.Universidade Federal de São Paulo, Nutr Program, São Paulo, BrazilUniversidade Federal de São Paulo, Div Nephrol, São Paulo, BrazilUniversidade Federal de São Paulo, Nutr Program, São Paulo, BrazilUniversidade Federal de São Paulo, Div Nephrol, São Paulo, BrazilWeb of Scienc