Inadequate Energy and Excess Protein Intakes May Be Associated With Worsening Renal Function in Chronic Kidney Disease

Abstract

Dietary energy and protein play important roles in chronic kidney disease (CKD). This study investigates the relationship between energy/protein intake status and renal function in CKD. This cross-sectional study included 599 adult patients diagnosed with stage 3 to 5 CKD in nephrology and nutrition outpatient clinics in Taiwan. Energy and protein intakes were assessed using 24-h dietary recall. We recorded recommended calorie/protein amounts and renal function indices, glomerular filtration rate (GFR), creatinine, and blood urea nitrogen (BUN). Patients were categorized into three intake calorie/protein groups by a ratio of actual intake vs. recommended intake. High intake was defined as a ratio of actual intake/recommended intake > or = 110%, moderate intake as > or = 90% to <110%, and low intake as <90%. Data were analyzed by paired t test, one-way analysis of variance, least significant differences, and multiple linear regression. The energy and protein intakes in CKD patients were significantly higher and lower than recommended levels (P < .001). Low energy intake was significantly related to worsening GFR at increments of -4.41 mL/min/1.73 m(2), compared with moderate and high energy intake (P = .008); high protein intake was also associated with worsening GFR at increments of -3.50 mL/min/1.73m(2), compared with moderate and low protein intake (P < .001). Low energy intake and high protein intake were significantly positively correlated with elevations in creatinine and BUN. Lower energy and higher protein intakes than recommended may be associated with deteriorating renal function.