Journal
BRITISH JOURNAL OF NUTRITION
Volume 102, Issue 8, Pages 1187-1194Publisher
CAMBRIDGE UNIV PRESS
DOI: 10.1017/S0007114509371779
Keywords
Green tea catechins; Caffeine; Energy expenditure; Substrate oxidation
Categories
Funding
- Unilever R&D Vlaardingen, The Netherlands
Ask authors/readers for more resources
Green tea may stimulate energy metabolism; however, it is unclear if acute effects are caused by specific catechins, caffeine or their combination. The objective of the present study was to examine the separate and combined effects of different catechins and caffeine on energy expenditure (EE) and fat oxidation over a single day. Fifteen healthy, normal-weight males received capsules containing placebo, caffeine alone (150mg), or caffeine plus a catechin mixture (600 mg) enriched in either epigallocatechin-3-gallate (EGCG), epigallocatechin or a mix of catechins, in a randomised cross-over double-blinded design. On each test day EE, respiratory quotient (RQ) and substrate oxidation were measured under sedentary conditions in a respiratory chamber for 13.5h. We found no significant treatment effect on EE (P=0.20) or RQ (P=0.68). EGCG with caffeine insignificantly raised EE and fat oxidation v. caffeine-only and placebo (EE 5.71 (SE 0.12) v. 5.68 (SE, 0.14) v. 5.59 (SE 0.13) MJ/12.5h, respectively; fat oxidation 84.8 (SE, 5.2) v. 80.7 (SE 4.7) v. 76.8 (SE 4.0) g/12.5h). Catechin/caffeine combinations at these dosages and mode of application had non-significant acute effects on EE and fat oxidation. The maximum observed effect on EE of about 2 % could still be meaningful for energy balance over much longer period of exposure. However, higher short-term effects reported in the literature may reflect variations in green tea extracts, added caffeine, or synergies with physical activity. The specific mechanisms and conditions that may underpin observed longer-term benefits of catechin-enriched green tea consumption on body composition remain to be confirmed.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available