Document Detail

Metabolic effects of caffeine in humans: lipid oxidation or futile cycling?
MedLine Citation:
PMID:  14684395     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Caffeine ingestion stimulates both lipolysis and energy expenditure. OBJECTIVES: Our objectives were to determine whether the lipolytic effect of caffeine is associated with increased lipid oxidation or futile cycling between triacylglycerol and free fatty acids (FFAs) and whether the effects of caffeine are mediated via the sympathetic nervous system. DESIGN: Respiratory exchange and [1-(13)C]palmitate were used to trace lipid oxidation and FFA turnover in 8 healthy, young men for 90 min before and 240 min after ingestion of placebo, caffeine (10 mg/kg), or caffeine during beta-adrenoceptor blockade. RESULTS: During fasting conditions, there were few differences in measured variables between the 3 tests. During steady state conditions (last hour of the test) after ingestion of caffeine, lipid turnover increased 2-fold (P < 0.005), and the mean (+/-SEM) thermic effect was 13.3 +/- 2.2% (P < 0.001), both of which were greater than after ingestion of placebo or caffeine during beta-adrenoceptor blockade. After ingestion of caffeine, oxidative FFA disposal increased 44% (236 +/- 21 to 340 +/- 16 micro mol/min), whereas nonoxidative FFA disposal increased 2.3-fold (455 +/- 66 to 1054 +/- 242 micro mol/min; P < 0.01). In postabsorptive conditions, 34% of lipids were oxidized and 66% were recycled. Caffeine ingestion increased energy expenditure 13% and doubled the turnover of lipids, of which 24% were oxidized and 76% were recycled. beta-Adrenoceptor blockade decreased, but did not inhibit, these variables. CONCLUSIONS: Many, but not all, of the effects of caffeine are mediated via the sympathetic nervous system. The effect of caffeine on lipid mobilization in resting conditions can be interpreted in 2 ways: lipid mobilization alone is insufficient to drive lipid oxidation, or large increments in lipid turnover result in small increments in lipid oxidation.
Kevin J Acheson; Gérard Gremaud; Isabelle Meirim; Franck Montigon; Yves Krebs; Laurent B Fay; Louis-Jean Gay; Philippe Schneiter; Charles Schindler; Luc Tappy
Related Documents :
11053335 - Preexercise carbohydrate ingestion, glucose kinetics, and muscle glycogen use: effect o...
2056905 - Dissociation of the ventilatory and lactate thresholds following caffeine ingestion.
2733575 - Gastric emptying: influence of prolonged exercise and carbohydrate concentration.
11474345 - Effect of caffeine and ephedrine ingestion on anaerobic exercise performance.
6258475 - Thermostabilization of enteroviruses by estuarine sediment.
1955625 - Effect of physical activity on the metabolism of magnesium in the rat.
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of clinical nutrition     Volume:  79     ISSN:  0002-9165     ISO Abbreviation:  Am. J. Clin. Nutr.     Publication Date:  2004 Jan 
Date Detail:
Created Date:  2003-12-19     Completed Date:  2004-01-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376027     Medline TA:  Am J Clin Nutr     Country:  United States    
Other Details:
Languages:  eng     Pagination:  40-6     Citation Subset:  AIM; IM    
Nestlé Research Center, Lausanne, Switzerland.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Adrenergic beta-Antagonists / pharmacology
Caffeine / blood,  pharmacology*,  urine
Central Nervous System Stimulants / blood,  pharmacology*,  urine
Energy Metabolism / drug effects*
Lipid Metabolism*
Lipolysis / drug effects*
Oxidation-Reduction / drug effects
Propranolol / pharmacology
Theophylline / blood
Reg. No./Substance:
0/Adrenergic beta-Antagonists; 0/Central Nervous System Stimulants; 525-66-6/Propranolol; 58-08-2/Caffeine; 58-55-9/Theophylline; 611-59-6/1,7-dimethylxanthine

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

Previous Document:  Body mass index and obesity-related metabolic disorders in Taiwanese and US whites and blacks: impli...
Next Document:  Plasma lycopene, other carotenoids, and retinol and the risk of cardiovascular disease in women.