The effect of dietary fiber type on glycated hemoglobin and renal hypertrophy in the adult diabetic rat

The effect of various dietary fiber sources on glycated hemoglobin and renal hypertrophy, two longterm indicators of blood glucose control, was studied in diabetic rats. Streptozotocin-treated rats were fed a fiber-free diet or diets containing 8% dietary fiber, using one of the following fiber sources: cellulose, sugar beet fiber, beet fiber treated with calcium carbonate, oat bran, rye bran, barley bran flour, wheat bran, or guar gum. After 28 days, only guar gumfeeding reduced the % glycated hemoglobin relative to the fiber-free control group. Renal hypertrophy was seen in animals from all diabetic groups and was not diminished by any of the fiber sources. In meal-fed animals there was no evidence of expansion of the intestinal contents volume by feeding of any fiber source. Guar gum substantially increased the viscosity of the intestinal contents in 3 of 4 animals. The results are consistent with the use of purified, highly viscous fiber sources for improving glycemic control in insulin-dependent diabetes.