Acute Fructose Administration Improves Oral Glucose Tolerance in Adults With Type 2 Diabetes

Acute Fructose Administration Improves Oral Glucose Tolerance in Adults With Type 2 Diabetes Mary Courtney Moore , PHD 1 , Stephen N. Davis , MD 1 2 3 , Stephnie L. Mann , BSN 2 and Alan D. Cherrington , PHD 1 2 3 1 Molecular Physiology and Biophysics and 2 Medicine and the 3 Diabetes Research and Training Center, Vanderbilt University, Nashville, Tennessee Abstract OBJECTIVE —In normal adults, a small (catalytic) dose of fructose administered with glucose decreases the glycemic response to a glucose load, especially in those with the poorest glucose tolerance. We hypothesized that an acute catalytic dose of fructose would also improve glucose tolerance in individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS —Five adults with type 2 diabetes underwent an oral glucose tolerance test (OGTT) on two separate occasions, at least 1 week apart. Each OGTT consisted of 75 g glucose with or without the addition of 7.5 g fructose (OGTT + F or OGTT – F), in random order. Arterialized blood samples were collected from a heated dorsal hand vein twice before ingestion of the carbohydrate and every 15 min for 3 h afterward. RESULTS —The area under the curve (AUC) of the plasma glucose response was reduced by fructose administration in all subjects; the mean AUC during the OGTT + F was 14% less than that during the OGTT – F ( P < 0.05). The insulin AUC was decreased 21% with fructose administration ( P = 0.2). Plasma glucagon concentrations declined similarly during OGTT – F and OGTT + F. The incremental AUC of the blood lactate response during the OGTT – F was ∼50% of that observed during the OGTT + F ( P < 0.05). Neither nonesterified fatty acid nor triglyceride concentrations differed between the two OGTTs. CONCLUSIONS —Low-dose fructose improves the glycemic response to an oral glucose load in adults with type 2 diabetes, and this effect is not a result of stimulation of insulin secretion. AUC, area under the curve GKRP, glucokinase regulatory protein IGT, impaired glucose tolerance NEFA, nonesterified fatty acid OGTT, oral glucose tolerance test OGTT + F, oral glucose tolerance test with addition of fructose OGTT – F, oral glucose tolerance test without addition of fructose Footnotes Address correspondence and reprint requests to Mary C. Moore, PhD, 702 Light Hall, Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-0615. E-mail: genie.moore{at}mcmail.vanderbilt.edu . Received for publication 25 May