Effects of Soybean Pectin on Blood Glucose and Insulin Responses in Healthy Men

The goal of this study was to examine the effects of soy pectin on postprandial plasma glucose and insulin responses in healthy adult males. A second goal was to analyze the subjects' intestinal microbiota to determine if differences in weight or body mass index would be linked to differences in microbiota populations. Pectin is a soluble fiber with demonstrated health benefits such as the ability to lower blood glucose and cholesterol, increase satiety leading to lower caloric intake, improve insulin resistance and lower inflammation. These benefits suggest that pectin may help in prevention and treatment of type II diabetes. Soy pectin is extracted from hulls, a waste product of soy processing in the food industry. Using a randomized-crossover design, thirty male subjects consumed two treatments (control glucose solution and glucose solution with added soy pectin) with a one-week washout period between the treatments. Baseline blood samples were collected 15 minutes prior to consumption and at 0, 15, 30, 45, 60, 75, 90, 120, and 180 minutes. Fecal samples were collected from 16 subjects (5 overweight/obese and 11 normal weight) to identify their gut microbiota profiles. Soy pectin reduced the postprandial plasma glucose and insulin levels. The mean incremental area under the curve (iAUC) responses of plasma glucose and insulin were reduced by ~10.4% and ~19.4%, respectively. With soy pectin, the insulin response was significantly lower at 30 minute (P<0.05). None of the time points for plasma glucose were statistically significant. Analysis of results based on subject BMI showed a greater lowering of glucose and insulin response in normal weight subjects than in overweight and obese subjects. Microbiota sequencing demonstrated an increase in the ratio of Bacteroidetes to Firmicutes in normal weight subjects compared to overweight subjects. Results suggest that soy pectin has potential to assist in improving plasma glucose and insulin concentrations.