title: Variable duration of decaffeinated green tea extract ingestion on exercise metabolism.
abstract: OBJECTIVE
  The aim of this study was to investigate if the duration of decaffeinated green tea extract (dGTE) ingestion plays a role in augmenting fat oxidation rates during moderate-intensity exercise.
  
  
  METHODS
  In a crossover, placebo-controlled design, 19 healthy males (mean ± SD; age = 21 ± 2 yr, weight = 75.0 ± 7.0 kg, body mass index = 23.2 ± 2.2 kg·m, maximal oxygen consumption [V˙O2max] = 55.4 ± 4.6 mL·kg·min) ingested dGTE and placebo (PLA) for 28 d, separated by a 28-d washout period. On the first day (dGTE 1 or PLA 1) and after 7 d (dGTE 7 or PLA 7) and 28 d (dGTE 28 or PLA 28), participants completed a 30-min cycle exercise bout (50% Wmax), 2 h after ingestion. Indirect calorimetry was used to calculate rates of whole-body fat and carbohydrate oxidation during exercise. Blood samples were collected at rest and during exercise for analysis of plasma fatty acids, glycerol, and epigallocatechin gallate.
  
  
  RESULTS
  The ingestion of dGTE did not significantly change whole-body fat oxidation rates during exercise on day 1, 7, or 28 compared with PLA. There were also no changes in plasma concentrations of fatty acids and glycerol at rest and during exercise as a result of dGTE ingestion at any time point compared with PLA. Plasma epigallocatechin gallate concentrations, immediately before the exercise bout, in the three dGTE trials were elevated compared with PLA but not different between 1, 7, and 28 d.
  
  
  CONCLUSIONS
  In contrast to previous reports, we found that the duration of dGTE ingestion had no effect on whole-body fat oxidation rates or fat metabolism-related blood metabolites during exercise in physically active healthy males.
authors.affiliation: 1Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Birmingham, UNITED KINGDOM; 2Unilever R&D, Colworth Science Park, Sharnbrook, Bedfordshire, UNITED KINGDOM; 3Unilever R&D, Vlaardingen, THE NETHERLANDS.
authors.forename: Rebecca K
authors.initials: RK
authors.lastname: Randell
authors.forename: Adrian B
authors.initials: AB
authors.lastname: Hodgson
authors.forename: Silvina B
authors.initials: SB
authors.lastname: Lotito
authors.forename: Doris M
authors.initials: DM
authors.lastname: Jacobs
authors.forename: Matthew
authors.initials: M
authors.lastname: Rowson
authors.forename: David J
authors.initials: DJ
authors.lastname: Mela
authors.forename: Asker E
authors.initials: AE
authors.lastname: Jeukendrup
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000328:Adult; D028241:Camellia sinensis; D050260:Carbohydrate Metabolism; D002392:Catechin / Q000031:analogs & derivatives / Q000097:blood; D018592:Cross-Over Studies; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005227:Fatty Acids / Q000097:blood; D005990:Glycerol / Q000097:blood; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000008:administration & dosage*; D013662:Tea
chemical_list: D005227:Fatty Acids; D010936:Plant Extracts; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate; D005990:Glycerol