But fat oxidation increases significantly only after ingestion of catechin-caffeine mixtures
MONDAY, March 28 (HealthDay News) -- Catechin-caffeine mixtures -- such as those found in green tea -- and caffeine-only supplementation increase daily energy expenditure, but only catechin-caffeine mixtures significantly increase daily fat oxidation, according to a meta-analysis published online March 2 in Obesity Reviews.
Rick Hursel, from Maastricht University in the Netherlands, and colleagues conducted a meta-analysis to compare the effect of catechin-caffeine mixtures and caffeine-only supplementation on thermogenesis and fat oxidation. Six studies, detailing 18 different conditions and reporting daily energy expenditure and fat oxidation after catechin-caffeine mixtures and caffeine-only supplementation, were identified by systemic literature searches until the beginning of 2010. The average difference in 24-hour energy expenditure and fat oxidation between supplemented and nonsupplemented conditions was computed, and the influence of moderators, such as body mass index and dosage, was evaluated.
The investigators found that energy expenditure increased significantly over 24 hours with both catechin-caffeine mixtures and caffeine-only supplementation, but that fat oxidation increased over 24 hours with catechin-caffeine combinations only (16.0 percent versus 12.4 percent with caffeine-only). The energy expenditure and 24-hour fat oxidation were dose dependent and occurred with an average increase of 0.53 kJ mg−1 and 0.02 g mg−1 for catechin-caffeine mixtures and 0.44 kJ mg−1 and 0.01 g mg−1 for caffeine-only.
"This meta-analysis shows that a catechin-caffeine mixture and caffeine-only have a stimulating effect on energy expenditure. Furthermore, a catechin-caffeine mixture has also a stimulating effect on fat oxidation compared with placebo," the authors write.
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