Effects of Olive Oil and Guar on Fructose-induced Insulin Resistance

Insulin resistance is a metabolic disorder consistent in a diminished response to insulin in insulin-sensitive tissues, and it is associated with some common diseases such as type 2 diabetes, hypertension, obesity, and myocardial infarction. Pharmacological intervention, moderate exercise, and diets are accepted as positive factors to ameliorate the insulin resistance. Fructose, as a free hexose or as sucrose, given in an intragastric bolus, favors D-glucose homeostasis rather than augmenting the hyperglycemic response to oral D-glucose intake. In spite of that, the long-term administration of D-fructose incorporated in either diet or drinking water is currently used as a model to induce insulin resistance in experimental animals. This chapter compares the two modalities of D-fructose administration and assesses the reversibility of the fructose-induced insulin resistance in normal rats, and finds that the enrichment of the diet with either powdered D-fructose (50%, w/w) or drinking water with the ketohexose (20%, w/v) leads to comparable metabolic changes. In both cases, a lesser gain in body weight was noticed in the fructose rats, even when these rats and the control animals displayed comparable body weight at the onset of the period under consideration; this coincided with a lower food intake in the fructose rats than in the control animals. The plasma D-glucose and insulin concentrations increased in the rats during exposure to the fructose-enriched diet or drinking water, while such was not the case in the control animals, and those increases were observed both in the fed state and after overnight fasting. © 2010 Copyright © 2010 Elsevier Inc. All rights reserved.