Submitted to: Journal of Pediatric Endocrinology & Metabolism
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/1/2007
Publication Date: 3/1/2008
Citation: Sunehag, A.L., Toffolo, G., Campioni, M., Bier, D.M., Haymond, M.W. 2008. Short term high dietary fructose intake had no effects on insulin sensitivity and secretion, or glucose and lipid metabolism in healthy, obese adolescents. Journal of Pediatric Endocrinology & Metabolism. 21(3):225-235. Interpretive Summary: There is virtually no information on the metabolic effects of dietary fructose intake in adolescents despite their high fructose consumption, particularly via sweetened beverages. In this study, we determined the metabolic effects of high fructose vs. a low fructose diet in obese insulin-resistant adolescents who were able to maintain normal blood sugar concentrations by increasing their insulin secretion. We measured production rates of glucose (sugar), lipolysis (breakdown of fat), the body's sensitivity to insulin and the secretion of insulin (using compounds labeled with non-radioactive, naturally occurring stable isotopes), concentrations of insulin, C-peptide, glucose and blood fats in the blood following an overnight fast, and triglyceride concentrations were measured five hours following the supper meal. We demonstrated that large differences in fructose intake had no effect on any of the metabolic parameters described above. We conclude that when energy intake is constant and corresponds to the energy needs, dietary fructose per se is not a contributor to insulin resistance and increased insulin secretion in obese adolescents.
Technical Abstract: There is virtually no information on the metabolic impact of dietary fructose intake in adolescents despite their high fructose consumption, particularly via sweetened beverages. To determine the short-term metabolic effects of dietary fructose intake in obese adolescents, six volunteers (3 M/3 F; 15.2 +/- 0.5 yr; 35 +/- 2 kg/m2; 39 +/- 2% body fat) were studied twice following 7 d of isocaloric, isonitrogenous high carbohydrate (60% CHO; 25% fat) diets, with fructose accounting for 6% and 24% of total energy intake, respectively (random order). Insulin sensitivity and secretion were analyzed by the stable labeled intravenous glucose tolerance test, and glucose and lipid kinetics using GCMS. A fourfold increase in dietary fructose intake did not affect insulin sensitivity or secretion, glucose kinetics, lipolysis or glucose, insulin, C-peptide, triglycerides, HDL- and LDL-cholesterol concentrations. In the short term, when energy intake is constant, dietary fructose per se is not a contributor to insulin resistance and hypersecretion in obese adolescents.