Effect of Dietary Fiber on Postprandial Blood Glucose Levels

Abstract

We investigated the difference in the inhibitory effect against a blood sugar level increase based on the fiber content of different types of vegetables. The subjects were 15 healthy subjects. There were 4 types of test diets: regular diet (1), 250 g of Kitsune noodles and 200 g of rice ("regular diet (1)"); fiber, a drink containing 4 g of indigestible dextrin ("test diet (2)"); radish salad ("test diet (3)"); and okra salad ("test diet (4)"). Regular diet (1) was ingested after finishing the dietary fiber for test diets (2) to (4). Blood glucose measurements were performed before meals and 15, 30, 60, and 120 minutes after meals. To compare the regular diet (1) group with each test diet, Wilcoxon's rank sum test was performed. A significant difference (Z= −2.075, p= 0.037) was observed 15 minutes after meals between the regular diet (1) group and the test diet (4) group. There were no significant differences at other times or between other diets tested. It was believed that viscous fiber had a better blood glucose suppression effect 15 minutes after meals than at other time points.