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Type 2 diabetes is highly prevalent in North America and is associated with increased risk of cardiovascular disease (CVD). Evidence from dietary interventions supports a role for soy protein in the reduction of serum lipids related to CVD risk, however few studies have focused on adults with type 2 diabetes. The purpose of this study was to determine the effect of consuming isoflavone-rich soy protein isolate (SPI) on serum lipids in adults with type 2 diabetes. Using a double-blind, randomized, crossover, placebo-controlled intervention study design, adults with diet-controlled type 2 diabetes (n=29) consumed SPI or milk protein isolate (MPI) for 57 days each separated by a 4-week washout period. Fasted blood samples were collected on days 1 and 57 of each treatment period and analyzed for serum lipids and apolipoproteins (apos). Results showed that serum LDL-cholesterol (chol), and the ratios of LDL-chol/HDL-chol and apoB/apoA-I were significantly reduced following consumption of SPI when compared to MPI (p=0.04, p=0.02 and p=0.05, respectively). There were no significant effects of SPI on other serum lipids (total-chol, HDL-chol, triglycerides) or individual apos (apoB, apoA-I). These data demonstrate that consumption of soy protein can modulate serum lipids in a direction beneficial for CVD risk in adults with type 2 diabetes. [ABSTRACT FROM AUTHOR]

Evidence from observational, animal and cell culture studies support a role for soy protein and its isoflavones in the improvement of glycemic control in type 2 diabetes. The objective of this study was to determine the effect of isoflavone-rich soy protein on markers of glycemic control in adults with type 2 diabetes. Using a double-blind, randomized, crossover, placebo-controlled intervention study design, adults with diet-controlled type 2 diabetes (n=29) consumed SPI or milk protein isolate (MPI) for 57 days each separated by a 4-week washout period. Fasting blood samples were collected on days 1 and 57 of each treatment period for analysis of fasting plasma glucose and glycated hemoglobin (HbA1C). An oral glucose tolerance test was also performed on days 1 and 57 of each treatment period for analysis of postprandial plasma glucose. Results showed no significant differences between treatments for fasting HbA1C, fasting plasma glucose or postprandial plasma glucose response, as summarized by area under the curve. These data do not support a role for soy protein in the improvement of glycemic control in adults with type 2 diabetes and contribute to a limited literature on the effects of soy protein on the management of type 2 diabetes. Supported by the Heart and Stroke Foundation of Ontario and the Solae Company. [ABSTRACT FROM AUTHOR]