Effects of soy consumption on oxidative stress, blood homocysteine, coagulation factors, and phosphorus in peritoneal dialysis patients.

OBJECTIVE: We studied the effects of soy consumption on oxidative stress, blood homocysteine, coagulation factors, and phosphorus in peritoneal dialysis patients. DESIGN: This was an unblinded, randomized clinical trial. SETTING: This study involved peritoneal dialysis centers in Tehran, Iran. PATIENTS: We included 40 peritoneal dialysis patients (20 males and 20 females). INTERVENTION: Peritoneal dialysis patients were randomly assigned to either a soy or control group. Patients in the soy group received 28 g/day textured soy flour (containing 14 g of soy protein) for 8 weeks, whereas patients in the control group received their usual diet, without any soy. MAIN OUTCOME MEASURES: Blood oxidized low-density lipoprotein (ox-LDL), homocysteine, phosphorus, fibrinogen concentrations, and the activities of coagulation factors VII, IX, and X were measured at baseline and at the end of week 8 of the study. RESULTS: The percentage of plasma coagulation factor IX activity decreased significantly by 17% in the soy group at the end of week 8 compared with baseline (P < .01), and the reduction was significant compared with the control group (P < .05). There were no significant differences between the two groups in mean changes of blood ox-LDL, homocysteine, phosphorus, fibrinogen concentrations, and the activities of coagulation factors VII and X. CONCLUSION: Soy consumption reduces plasma coagulation factor IX activity, which is a risk factor for thrombosis in peritoneal dialysis patients.

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

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 t-test, 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 (P<0.01), triglyceride (P<0.002) and LDL-c (P<0.04), urinary urea nitrogen and proteinuria (P<0.001) 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.