Beneficiary effect of dietary soy protein on lowering plasma levels of lipid and improving kidney function in type II diabetes with nephropathy

Abstract

Objective: Heart and renal diseases are two major problems in diabetic patients. Hyperlipidemia is one of the main risk factors of cardiovascular complications in diabetes. The type of protein consumed also affects the changes in renal blood flow, glomerular resistance and renal function in these patients. Hence, this study was undertaken to show the effect of soy protein consumption on lipid profiles and kidney function of diabetic patients with nephropathy, who attended an educational university hospital as well as a private kidney disease clinic in Tehran. Subjects and methods: This crossover randomized clinical trial was conducted on 14 patients who were free of any uncontrolled condition or other renal diseases. The patients were asked to follow a usual nephropathy diet (0.8 g/kg protein, 70% animal and 30% vegetable protein) for 7 weeks. After a washout period of 4 weeks consuming the prestudy diet, subjects were readmitted to repeat the same cycle with a similar diet containing 35% soy protein and 30% vegetable protein. Paired ttest, carryover effect and period effect were used for statistical analysis. Result: There were 10 men and four women whose mean (s.d.) of weight was 70.6 (10.3) kg. Significant reductions were seen in total cholesterol (Po0.01), triglyceride (Po0.002) and LDL-c (Po0.04), urinary urea nitrogen and proteinuria (Po0.001) after soy vs animal protein consumption. There were no significant changes in HDL-c, LDL-c/HDL-c levels. We also saw a favorable effect on renal function. Conclusion: Soy inclusion in the diet can modify the risk factors of heart disease and improve kidney function in these patients.

Soy Protein Intake, Cardiorenal Indices, and C-Reactive Protein in Type 2 Diabetes With Nephropathy

“…As diabetic nephropathy is a progressive disease, we expected that the conditions of these patients would have gotten worse after 4 years, but because of medical and dietary control, their conditions improved in some respects. It seems that soy protein consumption might have a favorable effect on diabetic nephropathy through its impact on serum lipid levels (4,19). The association between hypercholesterolemia and diabetic nephropathy was demonstrated earlier (20).…”

“…Although several short-term studies regarding the effect of soy on kidneyrelated biomarkers and cardiovascular Soy protein and diabetes risk factors are available (4,7,8), to our knowledge this is the first study in which such effects have been assessed for a long period of time (4 years). Thus, the results would be useful in interpreting the stability of soy effects.…”

“…Such a diet might adversely affect blood cholesterol and atherosclerosis (3). It seems that not only the quantity but also the type of protein have important implications in renal disease (4).…”

“…This new pathogenic perspective leads to some therapeutic considerations that can be considered in clinical treatments for diabetic nephropathy (6). Several studies have shown that substitution of soy protein for animal protein might have beneficial effects on lipid profiles (4,7,8), circulating levels of inflammatory biomarkers (9,10), and renal function indexes (4,11). However, most data available in this regard come from short-term clinical trials, and no study has assessed the long-term consumption of soy protein as a stable component of the diet.…”

Dietary soya protein during pregnancy and lactation in rats with hereditary kidney disease attenuates disease progression in offspring

“…Dietary manipulation with a vegetarian soya diet for as little as 8 or 16 weeks in nephrotic patients decreases proteinuria and vegetarians exhibit lower glomerular filtration rates than omnivores (Bosch et al 1983;Kontessis et al 1990;Barsotti et al 1991;D'Amico et al 1991;Gentile et al 1993). In diabetic patients, soya protein interventions have been shown to reduce glomerular hyperfiltration, proteinuria or albuminuria (Jibani et al 1991;Azadbakht et al 2003;Teixeira et al 2004;Stephenson et al 2005). Due to practical limitations, however, human studies to date have been of short duration and have not examined the effects of soya protein on renal histological damage.…”