Effect of dietary manipulation on the lipid abnormalities and urinary protein loss in nephrotic patients.

We performed two trials. The former was a multicentric trial on 24 untreated patients with nephrotic syndrome due to membranous nephropathy to ascertain whether or not a long-term reduction of protein intake reduces urinary protein loss. In a randomized cross-over design the patients ate sequentially each for 3 months a normal protein diet (1.1 +/- 0.3 g/kg/day of proteins) and a low-protein diet (0.7 +/- 0.1 g/kg/day). Both diets were low in fat (< 30% of total calories). Neither urinary protein excretion nor serum albumin concentration were significantly different at the end of the low protein diet period or the normal protein diet period. We found that after 6 months of dietary manipulation serum total and LDL-cholesterol were reduced by 24 and 27% from the values at the beginning of the run-in period, also the mean 24 h proteinuria was significantly lower. In the later trial, after a baseline control period of 2 months on free diet, 20 untreated nephrotic patients were fed for two months a vegetarian soy diet, low in fat (28% of total calories) and in proteins (0.71 +/- 0.36 g/kg ideal body weight/day). At the end of the diet period all patients ate the same free diet as in the baseline period for 2 more months. The soy diet induced highly significant decreases in total serum cholesterol (28%). LDL-cholesterol (33%), apolipoprotein B (19%), urinary protein excretion (32%), that reversed on discontinuation of the diet.(ABSTRACT TRUNCATED AT 250 WORDS)