Tea (Camellia sinensis, Theaceae) and
tea polyphenols have been studied for the prevention of
chronic diseases, including
obesity.
Obesity currently affects >20% of adults in the United States and is a risk factor for
chronic diseases such as type II diabetes,
cardiovascular disease, and
cancer. Given this increasing public health concern, the use of dietary agents for the prevention of
obesity would be of tremendous benefit. Whereas many laboratory studies have demonstrated the potential efficacy of
green or black tea for the prevention of
obesity, the underlying mechanisms remain unclear. The results of human intervention studies are mixed and the role of
caffeine has not been clearly established. Finally, there is emerging evidence that high doses of
tea polyphenols may have adverse side effects. Given that the results of scientific studies on dietary components, including
tea polyphenols, are often translated into dietary supplements, understanding the potential toxicities of the
tea polyphenols is critical to understanding their potential usefulness in preventing
obesity. In this review, we will critically evaluate the evidence for the prevention of
obesity by
tea, discuss the relevance of proposed mechanisms in light of
tea polyphenol bioavailability, and review the reports concerning the toxic effects of high doses of
tea polyphenols and the implication that this has for the potential use of
tea for the prevention of
obesity. We hope that this review will expose areas for further study and encourage research on this important public health issue.