Nutrition and Exercise COMBINED EFFECTS OF GLUCOSE AND FRUCTOSE ON FLUID ABSORPTION FROM HYPERTONIC CARBOHYDRATE-ELECTROLYTE BEVERAGES

Lambert, GP, Lanspa, SJ, Welch R, Shi, X. Combined Effects of Glucose and Fructose on Fluid Absorption from Hypertonic Carbohydrate-Electrolyte Solutions. JEPonline 2008;11(2):46-55. This study examined the effect of glucose and fructose, compared to glucose alone on water absorption from hypertonic carbohydrateelectrolyte solutions (CES) in the small intestine. Six solutions were perfused into the duodenojejunum and water flux was determined using the segmental perfusion technique. The solutions were: 1) 6% glucose, 2) 3% glucose + 3% fructose, 3) 8% glucose, 4) 4% glucose + 4% fructose, 5) 10% glucose, or 6) 5% glucose + 5% fructose. All solutions also contained 20 mEq sodium, 3 mEq potassium and flavoring/coloring to simulate commonly ingested CES. Water flux was related to osmolality (r = 0.79) and the 6% glucose, 3% glucose + 3% fructose, and 4% glucose + 4% fructose solutions promoted a greater (P < 0.05) water absorption rate than the 8% glucose, 10% glucose and 5% glucose + 5% fructose solutions. These results indicate increasing osmolality negatively affects fluid absorption, and this is attenuated in a moderately hypertonic 8% CES by using both fructose and glucose compared to glucose alone.