COMPARISON OF A VEGETABLE-BASED (SOYA) AND AN ANIMAL-BASED LOW-PROTEIN DIET IN PREDIALYSIS CHRONIC-RENAL-FAILURE PATIENTS

There is some experimental evidence to suggest that progression of chr onic renal failure (CRF) is slower on diets based on soya protein than on diets based on animal protein. We have compared the effect of a so ya-based vegetarian low-protein diet (VPD) and an animal-based low-pro tein diet (APD) in 15 patients with CRF. 15 patients with CRF (Cr-51-E DTA-measured glomerular filtration rate 15-50 mi/min/1.73 m(2)) were s tudied. In a randomized crossover trial, the patients were given each diet (each containing 0.75 g protein and 32 kcal per kilogram body wei ght) for a 6-month period. Nine patients completed the trial, 2 others dropped out because they could not tolerate the VPD, 3 because of unr elated medical complications, and 1 for technical reasons. The caloric intake was higher and the protein, phosphate and essential amino acid intake lower on the VPD than on the APD. The compliance with the sugg ested caloric intake was better with the VPD than with the APD (97 vs. 88% of recommended intake), as was the compliance with the suggested protein intake (94 vs. 112% of recommended intake) and with the sugges ted phosphate intake (102 vs. 116%). The mean glomerular filtration ra te, as judged by Cr-51-EDTA, was similar after 6 months on each diet a nd remained unchanged throughout the entire year of the study. The rat e of fall of glomerular filtration, as measured by the slope of 1/seru m creatinine was slowed by 73% during the 1-year study period as compa red with the prestudy period. Nutritional status (as measured by body mass index, midarm circumference, and lean body mass and percent body fat), serum transferrin, cholesterol and albumin, and total lymphocyte count were similar on the two diets. The serum albumin level on both diets, however, was significantly higher on the two diets than during the prediet period. Blood urea nitrogen, urine urea nitrogen, protein catabolic rate, and 24-hour urine creatinine and phosphate were lower on the VPD than on the APD. The 24-hour protein excretion was similar on the two diets. The two low-protein diets resulted in a slowing in t he progression of CRF. A VPD is well tolerated in CRF and is associate d with lower protein and phosphate intakes and a higher caloric intake than an APD and may, therefore, be used as a safe alternative or part ial substitute for the usual APD in CRF.