A recently developed indigestible
dextrin (IDex) was studied for its effects on
glucose tolerance in male Sprague-Dawley rats. IDex is a low viscosity, water-soluble dietary fibre obtained by heating and
enzyme treatment of potato
starch. It has an average molecular weight of 1600. An oral
glucose tolerance test was conducted with 8-week-old rats to evaluate the effects of IDex on the increase in plasma
glucose and
insulin levels after a single administration of various
sugars (1.5 g/kg
body weight). The increase in both plasma
glucose and
insulin levels following
sucrose,
maltose and
maltodextrin loading was significantly reduced by IDex (0.15 g/kg
body weight). This effect was not noted following
glucose, high
fructose syrup and
lactose loading. To evaluate the effects of continual IDex ingestion on
glucose tolerance, 5-week-old rats were kept for 8 weeks on a stock diet, a high
sucrose diet or an IDex-supplemented high
sucrose diet. An oral
glucose (1.5 g/kg
body weight) tolerance test was conducted in week 8. Increases in both plasma
glucose and
insulin levels following
glucose loading were higher in the rats given a high
sucrose diet than in the rats fed a stock diet. However, when IDex was included in the high
sucrose diet, the impairment of
glucose tolerance was alleviated. Moreover, IDex feeding also significantly reduced accumulation of body fat, regardless of changes in
body weight. These findings suggest that IDex not only improves
glucose tolerance following
sucrose,
maltose and
maltodextrin loading but also stops progressive decrease in
glucose tolerance by preventing a high
sucrose diet from causing
obesity.