Forskning

August 9, 2011

The effects of catechin rich teas and caffeine on energy expenditure and fat oxidation: a meta-analysis

R Hursel et al, The effects of catechin rich teas and caffeine on energy expenditure and fat oxidation: a meta-analysis, Obesity Reviews, 2011, Volume 12.

Different outcomes of the effect of catechins-caffeine mixtures and caffeine only supplementation on energy expenditure and fat oxidation have been reported in short-term studies. This meta-analysis was conducted to elucidate whether catechins-caffeine mixtures and caffeine only supplementation indeed increase thermogenesis and fat oxidation. English-language studies measuring daily energy expenditure and fat oxidation by means of respiration chambers after catechins-caffeine mixtures and caffeine only supplementation were identified through Pub Med. Six studies encompassing  a total of 18 different conditions fitted the inclusion criteria. Results were aggregated using random/mixed effects models and expressed in terms of the mean difference in 24 hour energy expenditure and fat oxidation between the treatment and placebo conditions. Finally, the influence of moderators such as BMI and dosage on the results was examined as well. The catechins-caffeine mixtures and caffeine only supplementation increased energy expenditure significantly over 24 hours. However, 24 hour fat oxidation was only increased by catechins-caffeine mixtures. A dose-response effect on 24 hour energy expenditure and fat oxidation occurred with a mean increase of 0.53 kj mg and 0.02 g mg for catechin-caffeine mixtures and 0.44 kj mg and 0.01g mg for caffeine only. In conclusion, ‘catechin-caffeine mixtures or a caffeine-only supplementation stimulates daily energy expenditure dose-dependently by 0.4-0.5 kj mg administered. Compared with placebo, daily fat oxidation was only significantly increased after catechins-caffeine mixtures ingestion’.