Objective: The aim of the present study was to evaluate the effect of a soy-protein diet on plasma lipid levels of renal transplant recipients with moderate hypercholesterolemia.
Design: Dietary intervention case-control observational study.
Setting: Renal transplantation outpatient clinic.
Patients: Fifteen stable patients who had renal transplantation (serum creatinine < 2 mg/dL) with moderate hypercholesterolemia (low-density lipoprotein [LDL] cholesterol > 140 mg/dL).
Intervention: After a baseline dietary interview, dietary counseling was given individually with the goal of substituting 25 g of animal protein with 25 g of soy protein for a 5-week period, using commercially available soy foods, according to each patient's own preference. Main outcome measures Before and after the soy-diet period, plasma lipid profiles including total, LDL, and high-density lipoprotein (HDL) cholesterol, triglycerides, apolipoprotein A1 and B were determined. Protein catabolic rate was assumed as a measure of dietary protein intake.
Results: Two patients dropped out. After the soy diet, total cholesterol (254 +/- 22 to 231 +/- 31 mg/dL, P <.05) and LDL cholesterol (165 +/- 20 versus 143 +/- 20 mg/dL, P <.01) decreased significantly. No significant changes were observed regarding HDL cholesterol and triglycerides. Dietary protein intake did not differ at baseline (73.2 +/- 22.9 g/day) and during the soy diet (72.6 +/- 15.6 g/day), when the reported actual soy protein intake resulted 26 +/- 8 g/day.
Conclusions: This study shows that soy proteins given as part of the daily protein intake have beneficial effects on serum LDL cholesterol levels of renal transplant recipients with moderate hypercholesterolemia. Soy proteins could be of use in the nutritional management of renal transplant recipients.