Cancer is the major public health problem, causing approximately 7 million deaths every year worldwide. The existing treatment approaches and surgical techniques have not been able to cope effectively with this dreaded disease. Because of this, the concept of chemoprevention is now considered a valid approach to reduce the incidence of cancer. There is convincing epidemiological and experimental evidence to show that dietary polyphenolic plant-derived compounds have cancer preventive properties. Based on evidence from in vitro, in vivo data and epidemiological studies, tea has received considerable attention over recent years for reducing the risk of several cancers. Much of the cancer preventive effects of tea, and in particular green tea, appear to be mediated by the polyphenols they contain. In addition to inhibiting mutagenesis and proliferation, tea is relatively non-toxic, is low cost, and can be taken orally or as a part of the daily diet. Therefore it is logical that future clinical studies should focus on examining the efficacy of tea and its active constituents, such as epigallocatechin- 3-gallate (EGCG) and theaflavins (TFs), in chemoprevention as an alternative to pharmacological agents. In this review, we address the use of tea and its constituents for the prevention and treatment of cancer. Further mechanistic and dose-response studies will help us to understand the effects of tea consumption on human carcinogenesis.
Tea - Cancer - Epidemiology - Chemoprevention - Polyphenols