Whole grain consumption does not slow diabetic progression in GK rats

Abstract

Whole grain consumption is inversely associated with risk of type II diabetes epidemiologically. The aim of this study was to study the effect of whole grain consumption on diabetic control and progression in an animal model of type II diabetes, the Goto‐Kakisaki (GK) rat. GK rats were fed either a whole grain‐free control diet or a whole grain‐containing diet for 5 months. Whole grain diets contained 65% whole grain flours of either wheat, barley, oat, or corn. After two months, fasting plasma glucose concentration was significantly lower with the wheat, barley, or oat diets compared to the control diet. However, glycated hemoglobin was significantly greater in the wheat group compared to other groups. At 5 months, whole grain diets did not improve glycemic control. Fasting plasma insulin and C‐Peptide levels were decreased from month 2 to month 5 indicating diabetic progression. Insulin resistance, determined by the homeostasis model assessment, was not significantly different among groups at either 2 or 5 months. However, there was a trend for improvement of insulin resistance with the barley and oat diets at 2 months (P=0.06). There were no significant differences in the total pancreatic β‐cell mass among groups. These results offer little support for improvement of diabetic control and delayed progression with consumption of whole grains. (Supported by the General Mills Bell Inst. of Health and Nutrition)Grant Funding SourceGeneral Mills Bell Inst. of Health and Nutrition