Invited Review CALL FOR PAPERS Physiology and Pharmacology of Temperature Regulation Obesity and thermogenesis related to the consumption of caffeine, ephedrine, capsaicin, and green tea

Diepvens, Kristel, Klaas R. Westerterp, and Margriet S. Westerterp-Plantenga. Obesity and thermogenesis related to the consumption of caffeine, ephedrine, capsaicin, and green tea. Am J Physiol Regul Integr Comp Physiol 292: R77–R85, 2007. First published July 13, 2006; doi:10.1152/ajpregu.00832.2005.—The global prevalence of obesity has increased considerably in the last decade. Tools for obesity management, including caffeine, ephedrine, capsaicin, and green tea have been proposed as strategies for weight loss and weight maintenance, since they may increase energy expenditure and have been proposed to counteract the decrease in metabolic rate that is present during weight loss. A combination of caffeine and ephedrine has shown to be effective in long-term weight management, likely due to different mechanisms that may operate synergistically, e.g., respectively inhibiting the phosphodiesterase-induced degradation of cAMP and enhancing the sympathetic release of catecholamines. However, adverse effects of ephedrine prevent the feasibility of this approach. Capsaicin has been shown to be effective, yet when it is used clinically it requires a strong compliance to a certain dosage, that has not been shown to be feasible yet. Also positive effects on body-weight management have been shown using green tea mixtures. Green tea, by containing both tea catechins and caffeine, may act through inhibition of catechol O-methyl-transferase, and inhibition of phosphodiesterase. Here, the mechanisms may also operate synergistically. In addition, tea catechins have antiangiogenic properties that may prevent development of overweight and obesity. Furthermore, the sympathetic nervous system is involved in the regulation of lipolysis, and the sympathetic innervation of white adipose tissue may play an important role in the regulation of total body fat in general.