Soy-protein consumption and kidney-related biomarkers among type 2 diabetics: a crossover, randomized clinical trial.
OBJECTIVE
Renal disease is a major problem among diabetic patients. The type of protein consumed may affect alterations in kidney-related biomarkers in these patients. This study sought to assess the effects of soy-protein consumption on renal-related markers among type 2 diabetic patients with nephropathy.


METHODS
A crossover, randomized clinical trial was conducted among 14 patients (10 men and 4 women). One diet contained 0.8 g/kg protein (70% animal and 30% vegetable proteins), and a similar diet contained the same amount of protein with 35% animal protein, 35% soy protein, and 30% other vegetable proteins. These two diets were prescribed in each phase of the trial for 7 weeks. There was a 4-week washout between the two phases of the study.


RESULTS
Consumption of soy protein reduced urinary urea nitrogen (-0.9 +/- 0.8 vs. 0.2 +/- 0.6 mg/dL, respectively, SD; P < .001), proteinuria (-78 +/- 37 vs. 42 +/- 39 mg/day, respectively, SD; P < .001), blood sodium (-2 +/- 0.04 vs. 2.0 +/- 0.06 mg/dL, respectively, SD; P < .01), and serum phosphorus (-0.03 +/- 0.2 vs. 0.2 +/- 0.3 mg/dL, respectively, SD; P < .01) compared with animal protein. Serum and urinary creatinine, blood urea nitrogen, serum calcium, and potassium levels were not significantly changed in soy-protein versus anima-protein consumption.


CONCLUSION
Soy-protein consumption reduces proteinuria in type 2 diabetes with nephropathy.