Original Article Assessment of Protein Intake in Early Progressive Renal Disease

Abstract. Mean protein intake in a 4-day dietary survey of 34 patients with early renal disease was 1.2±0.27 g/kg ideal body weight daily. Nine subjects were taking over twice the recommended minimum intake. An increased protein intake was associated with a greater phosphate and sodium intake and an increased excretion of urea, phosphate, and sodium. Daily intake fluctuated mar-kedly during the study (coefficient of variance 22.5±10.9%). Protein catabolic rate calculated from urea excretion correlated with protein intake, r=0.60. Mean difference between the two estimates was 0.04±0.28 g/kg per day. It is proposed that if urea excretion exceeds 4.5 mmol/kg per day in a single collection (protein catabolic rate 0.98 g/kg per day), serial measurements should be made to determine protein intake more accurately and give dietary advice. Key words: Protein intake; Urea excretion; Renal failure all contribute [2]. Phosphate retention causes further damage [3]. Protein meals increase glomerular perfusion and provide a phosphate load [4], therefore low-protein diets are widely used in chronic renal failure with the intention of delaying its progress. They are not usually started until renal function has considerably declined. However, adult Western diets often contain much more protein than is necessary for nitrogen balance and it has been suggested that this might accelerate renal damage even in patients with early progressive renal disease [5]. We therefore measured the protein intake of patients with early potentially progressive renal disease on unrestricted diet to determine in how many protein intake was unnecessarily high, how variable it was, and whether high protein intake could be detected by simple methods