Dietary treatment of diabetic nephropathy with chronic renal failure.

Thirty-two patients with diabetes mellitus (22 IDDM and 10 NIDDM, 21 males and 11 females, age 44+/-11.8 years) were followed for 5.2+/-3.8 years after the onset of chronic renal failure, with the aim of evaluating the effect of low protein diets on the rate of decline of the residual renal function. During the 1.8+/-1.6 year follow-up period on free or uncontrolled low protein diet the mean rate of decline of creatinine clearance was 0.9+/-0.6 ml/min/month, significantly greater than that observed during 3.7+/-3.1 years on low or very low protein diets. The reduction of protein intake was followed by a significant decrease in daily urinary protein loss. A better glycaemic control was obtained on the low protein diet, and the daily insulin requirement decreased. The anthropometry, as well as the serum concentrations of rapid turnover proteins, did not change, in spite of the low or very low protein dietary supply for a long duration. The values of mean arterial pressure were quite similar during the follow-up period on free or uncontrolled low protein diet and during the study period on the low protein diet. A good compliance with reduced dietary intake (as demonstrated by the measurement of the daily urea excretion) was obtained in a large number of patients. In conclusion, our study confirms the protective effect on the residual renal function of low protein diets in IDDM and NIDDM patients with chronic renal failure due to diabetic nephropathy, in the absence of any sign of protein malnutrition.