Dr. U. Eggert

Conservative therapy of patients with chronic renal failure includes dietary measures designed to reduce uremic symptoms, to delay the onset of dialysis or transplantation and to improve the survival on dialysis.

A lot of clinical studies, including the recent MDRD-Study have reported about the beneficial effects of low protein diets (LPD: 0,6 g protein/kg body weight/day) and very low protein diets (VLPD: 0,3 g protein/kg body weight/day) supplemented with keto-/amino acids on renal function and on uremic symptons in both non-diabetic and diabetic renal failure. Especially the supplemented VLPD has been identified as a good dietary treatment regime in order to reduce the progression of renal failure and to improve various metabolic complications including metabolic acidosis, proteinuria, phospho-calcic-metabolism-disorders as well as disturbances of the carbohydrate and lipid metabolism in CRF;

Disturbances in the calcium-phosphate metabolism, indicated by hyperphosphatemia, hypocalcemia, secondary hyperparathyroidism as well as bone abnormalities are frequent in CRF patients. A lot of studies have shown the therapeutical effect of supplemented VLPD. The reduction of the phosphate intake due to the use of vegetarian diets as well as the presence of calcium (calcium salts of the ketoacids) is responsible for the correction of the serum calcium and phosphate levels, of the secondary hyperparathyroidism and the subsequent improvement of renal osteodystrophies.

Abnormalities in glucose metabolism have been recognized in approximately 50% of patients with CRF. Most of them manifest mild fasting hyperglycemia and abnormal glucose tolerance tests in spite of permanent hyperinsulinemia, suggesting a reduced sensitivity to the action of insulin. A lot of studies have shown, that supplemented VLPDs are able to correct most of the disorders of carbohydrate metabolism observed in uremia. Beneficial effects include the improvement in tissue sensitivity to insulin even in uremic diabetic patients and the reduction in circulating insulin levels in relation to an increase in the metabolic clearance rate of insulin.

The most mentioned criticism in concern with protein-restricted diets is the potential risk of developing malnutrition. However, a lot of studies have demonstrated that positive or neutral nitrogen balances, stable values of anthropometric parameters and improved values of serum albumin can be achieved in patients with CRF who received a supplemented VLPD. Even it has been shown that the prolonged administration of a supplemented VLPD during predialysis can significantly lower the mortality during the first 2 years on dialysis.

Further attempts in improving the predialysis and dialysis patients´quality of life have been made by adding the detoxifying effects of dialysis and of the conservative nutritional treatment. Patients on this combined therapy, who were carefully recruited and monitored, could be successfully treated.

Conclusion: The retardation of the progression rate of renal failure and the improvement of metabolic disturbances after the use of supplemented VLPD during predialysis improves the patient´s quality of life and reduces costs due to the delay of the onset of dialysis treatment. Furthermore supplemented VLPDs improve the nutritional status and reduces the mortality rate during dialysis.