Abstract

Background: Several short-term trials on the effect of soy consumption on cardiovascular risks are available, but little evidence exists regarding the impact of long-term soy protein consumption among type 2 diabetic patients with nephropathy.

Objectives: To determine the effects of long-term soy consumption on cardiovascular risks, C-reactive protein and kidney-function indices among type 2 diabetic patients with nephropathy.

Design: This longitudinal randomized clinical trial was conducted among 41 type 2 diabetic patients with nephropathy (18 men and 23 women). Twenty patients in soy protein group consumed a diet containing 0.8 g protein/kg body weight (35% animal proteins, 35% textured soy protein, and 30% vegetable proteins) and 21 patients in control group consumed a similar diet containing 70% animal proteins and 30% vegetable proteins for 4-years.

Results: Soy protein consumption significantly affected cardiovascular risks like fasting plasma glucose (mean change in soy vs. control groups: -18±3 vs. 11±2 mg/dl; P=0.03), total cholesterol (-23±5 vs.10±3 mg/dl; P=0.01), LDL-C (-20±5 vs. 6±2 mg/dl; P=0.01), and serum triglyceride concentrations (-24±6 vs. -5±2 mg/dl; P=0.01). Serum CRP levels was significantly decreased by soy protein intake as compared to control group (1.31±0.6 vs. 0.33±0.1 mg/L; P=0.02). Significant improvements were also seen in proteinuria (-0.15±0.03 vs. 0.02±0.01 g/d; P=0.001) and urinary creatinine (-1.5±0.9 vs. 0.6±0.3 mg/dl, P=0.01) by consuming soy protein.

Conclusions: Longitudinal soy protein consumption significantly affected cardiovascular risk factors and kidney-related biomarkers among type 2 diabetic patients with nephropathy.