[Objectives of the low-protein diet]

The prescription of low-protein diets to patients with chronic kidney disease has several objectives: to lower the dietary phosphorus load and circulating phosphorus and parathyroid hormone levels, and to improve the acid-base control and uremic symptoms while preserving the nutritional status. However, such objectives are always subordinate to the necessity of maintaining adequate calorie intake. An important target of any reduction of dietary protein intake is the delay of renal death and start of dialysis, as demonstrated by several methodologically sound studies and meta-analyses. However, no prospective study has yet confirmed the nephroprotective potential of low-protein diets repeatedly shown in animal models. Such negative results in human studies could be explained by their frequent methodological flaws, as well as by the modest actual reduction of protein intake compared with pre-study levels. The recent Cochrane meta-analysis confirmed that reducing dietary protein intake can delay renal death and dialysis. The Number-to-Treat estimate in the Cochrane meta-analysis (NNT=16) was even better than similar estimates in the statin prevention trials ''4S'' and ''WOSCOPS''.