ATTENUATION OF THE MEAL-INDUCED INCREASE IN PLASMA-LIPIDS AND ADIPOSE-TISSUE LIPOPROTEIN-LIPASE BY GUAR GUM IN RATS

This study was designed to evaluate the effect of guar gum on the postprandial increase in plasma lipids, insulin and lipoprotein lipase (LPL) activity in white adipose tissue (WAT). Male rats were given ad libitum access to purified diets containing either no fiber or 5% guar gum for 3 wk. The animals were killed at various times after a meal (10% of daily ad libitum intake of their respective diets). Consumption of guar gum resulted in smaller final body weight (-7%, P<0.05) and ad libitum food intake (-10%, P<0.05). The difference in epididymal WAT weight induced by the concomitant diet was relatively larger (-29%, P<0.05) than that of whole body weight. Although no difference was seen in fasting plasma total and high density lipoprotein cholesterol levels between dietary groups, the postprandial increase in these variables was larger in the animals given the fiber-free meal than in those receiving the fiber-supplemented meal (P<0.01). Guar also attenuated the postprandial rise in plasma triacylglycerols. The presence of fiber in the meal reduced the postprandial increase in plasma insulin (P<0.01). The meal-induced rise in LPL activity of WAT was significantly smaller (P<0.02) in the animals fed the diet containing fiber than in those receiving the fiber-free diet. Thus, guar gum altered the activity of LPL in WAT, an effect that may be related to the insulin response to this dietary component. The present results suggest that postprandial modulation of LPL activity in WAT may constitute another mechanism by which guar gum influences the metabolism of circulating lipoproteins.