Glycemic Response of Whole Grain Wheat Meals

It is generally assumed that whole grain foods confer a health benefit in regards to moderated glycemia and increased satiety compared to foods made from refined grains. However, the extent of whole grains' low glycemic property may be limited by certain factors. For example, physical properties such as viscosity or particle size and differing starch digestion rates of whole grain foods may strongly influence glycemic response and gastric emptying rate. In this study, whole and refined grain wheat porridges were prepared from materials originating from the same milling source, with matched pairs for viscosity, starch and dietary fiber contents, and particle size. Subjects consumed wheat porridges containing 13C-labeled octanoic acid for assessment of gastric emptying rate, and they wore a continuous glucose monitor for measuring postprandial glucose levels. The purpose of this research was to test the hypothesis that the purported moderated glycemic response and slow gastric emptying rate are dependent on how these foods are processed. This work highlights the need to consider specific properties of whole grain foods for desired health outcomes in order to optimize the design of whole grain-based foods.