Document Detail

Fructose and glucose co-ingestion during prolonged exercise increases lactate and glucose fluxes and oxidation compared with an equimolar intake of glucose.
MedLine Citation:
PMID:  20826630     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: When fructose is ingested together with glucose (GLUFRU) during exercise, plasma lactate and exogenous carbohydrate oxidation rates are higher than with glucose alone. OBJECTIVE: The objective was to investigate to what extent GLUFRU increased lactate kinetics and oxidation rate and gluconeogenesis from lactate (GNG(L)) and from fructose (GNG(F)). DESIGN: Seven endurance-trained men performed 120 min of exercise at ≈60% VO₂max (maximal oxygen consumption) while ingesting 1.2 g glucose/min + 0.8 g of either glucose or fructose/min (GLUFRU). In 2 trials, the effects of glucose and GLUFRU on lactate and glucose kinetics were investigated with glucose and lactate tracers. In a third trial, labeled fructose was added to GLUFRU to assess fructose disposal. RESULTS: In GLUFRU, lactate appearance (120 ± 6 μmol · kg⁻¹ · min⁻¹), lactate disappearance (121 ± 7 μmol · kg⁻¹ · min⁻¹), and oxidation (127 ± 12 μmol · kg⁻¹ · min⁻¹) rates increased significantly (P < 0.001) in comparison with glucose alone (94 ± 16, 95 ± 16, and 97 ± 16 μmol · kg⁻¹ · min⁻¹, respectively). GNG(L) was negligible in both conditions. In GLUFRU, GNG(F) and exogenous fructose oxidation increased with time and leveled off at 18.8 ± 3.7 and 38 ± 4 μmol · kg⁻¹ · min⁻¹, respectively, at 100 min. Plasma glucose appearance rate was significantly higher (P < 0.01) in GLUFRU (91 ± 6 μmol · kg⁻¹ · min⁻¹) than in glucose alone (82 ± 9 μmol · kg⁻¹ · min⁻¹). Carbohydrate oxidation rate was higher (P < 0.05) in GLUFRU. CONCLUSIONS: Fructose increased total carbohydrate oxidation, lactate production and oxidation, and GNG(F). Fructose oxidation was explained equally by fructose-derived lactate and glucose oxidation, most likely in skeletal and cardiac muscle. This trial was registered at as NCT01128647.
Virgile Lecoultre; Rachel Benoit; Guillaume Carrel; Yves Schutz; Grégoire P Millet; Luc Tappy; Philippe Schneiter
Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2010-09-08
Journal Detail:
Title:  The American journal of clinical nutrition     Volume:  92     ISSN:  1938-3207     ISO Abbreviation:  Am. J. Clin. Nutr.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-10-21     Completed Date:  2010-11-09     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0376027     Medline TA:  Am J Clin Nutr     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1071-9     Citation Subset:  AIM; IM    
Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
Data Bank Information
Bank Name/Acc. No.:
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Blood Glucose / metabolism*
Cross-Over Studies
Exercise / physiology*
Fructose / metabolism,  pharmacology*
Gluconeogenesis / drug effects*
Glucose / metabolism,  pharmacology*
Lactic Acid / metabolism*
Oxygen Consumption
Single-Blind Method
Reg. No./Substance:
0/Blood Glucose; 30237-26-4/Fructose; 50-21-5/Lactic Acid; 50-99-7/Glucose

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Nonprescribed physical activity energy expenditure is maintained with structured exercise and implic...
Next Document:  Trends in 24-h urinary sodium excretion in the United States, 1957-2003: a systematic review.