The Role of Dietary Protein in the Progression and Symptomatology of Chronic Renal Failure

Abstract

Dietary factors may have substantial impact on the clinical manifestations and even the progression of chronic renal failure. Proper dietary management can prevent certain uremic complications, decrease azotemia, and may even prevent the loss of residual renal function. Recent studies indicate that dietary protein may accelerate the normal age-related deterioration of renal function in rats. The extensive ablation of functional renal mass in rats leads to hyperemia and hyperfiltration in remnant nephrons. Continued hyperfiltration theoretically results in glomerular damage, proteinuria, and ultimately glomerular sclerosis. Dietary protein restriction reduces the remnant nephron hyperfiltration and reduces the rate of glomerular sclerosis, at least in the rat. The role of dietary protein in the pathogenesis of human nephrosclerosis remains controversial. Though dietary factors may or may not affect the rate of progression of renal insufficiency, there is no doubt that proper dietary management can limit or forestall uremic symptoms and the need for dialysis. Diets containing about 0.5 gm protein/kg body weight/day usually maintain a neutral or slightly positive nitrogen balance, while lesser amounts usually result in malnutrition. When protein intake exceeds 0.5 gm/kg/day azotemia increases dramatically. The use of nitrogen-free keto- or hydroxy-analogues of amino acids promotes positive nitrogen balance while reducing azotemia in patients with near-end-stage renal disease.