title: Effects of green tea extracts on non-shivering thermogenesis during mild cold exposure in young men.
abstract: The effects of epigallocatechin-3-gallate (EGCG) and caffeine on non-shivering thermogenesis (NST) during cold exposure is unknown. The purpose of the present study was to quantify the effects of co-ingesting EGCG and caffeine on the thermogenic responses of a 3 h cold exposure. A total of eight healthy males were exposed to mild cold, using a liquid-conditioned suit perfused with 158C water, on two occasions and consumed a placebo or an extract of 1600 mg of EGCG and 600 mg of caffeine (Green tea). Thermic, metabolic and electromyographic measurements were monitored at baseline and during the cold exposure. Results showed that the AUC of shivering intensity over the cold exposure period was reduced by approximately 20% in the Green tea (266 (SEM 6)% maximal voluntary contraction (MVC) x min) compared with the Placebo (332 (SEM 69)%MVC x min) (P=0·01) treatments. In contrast, the total AUC for energy expenditure (EE) was approximately 10% higher in the Green tea (23·5 (SEM 1·4) kJ/kg x 180 min) compared with the Placebo (327 (SEM 74) kJ/kg 180 min) (P=0·007) treatments. The decrease in shivering activity combined with an increase in EE, following the ingestion of EGCG and caffeine during the cold exposure, indicates that NST pathways can be significantly stimulated in adult human subjects. The present study provides an experimental approach for human investigations into the potential role of diet and bioactive food ingredients in modulating NST during cold exposure. Stimulating NST pathways in such a manner may also provide important targets in the search of targets for the management of obesity and diabetes.
authors.affiliation: Unité de Recherche sur Nutrition et Métabolisme, Hôpital Montfort, 713, Chemin Montréal, Ottawa, ON, Canada K1K 0T2.
authors.forename: Chantal
authors.initials: C
authors.lastname: Gosselin
authors.forename: François
authors.initials: F
authors.lastname: Haman
mesh_terms: D000328:Adult; D019540:Area Under Curve; D002110:Caffeine / Q000494:pharmacology*; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D003080:Cold Temperature; D003920:Diabetes Mellitus / Q000188:drug therapy; D004032:Diet; D004734:Energy Metabolism / Q000187:drug effects*; D006801:Humans; D008297:Male; D009765:Obesity / Q000188:drug therapy; D010936:Plant Extracts / Q000494:pharmacology; D012768:Shivering; D013662:Tea; D022722:Thermogenesis / Q000187:drug effects*; D055815:Young Adult
chemical_list: D010936:Plant Extracts; D013662:Tea; D002110:Caffeine; D002392:Catechin; C045651:epigallocatechin gallate