ABSTRACT

There is sufficient evidence that dietary and nutritional factors are of great importance in the causation of human cancer, and the imbalance between dietary carcinogens and anticarcinogens may play an important role in the development of human cancer (Cheng and Ho, 1988). Epidemiological studies have shown that the incidence of certain kinds of human cancer is relatively low in communities where fresh vegetables and fruits are frequently consumed (Block et al. 1992). It is generally recognized that naturally occurring substances in the food consumed are one of the most promising sources of inhibitors of carcinogenesis. The search for natural edible products which might have a preventive effect on human cancer has thus attracted the attention of many scientists. Since 1984, we have studied over 100 varieties of fresh vegetables, fruits and beverages for their antimutagenicity (Luo et al. 1987). Green tea, among others, was found to be highly antimutagenic. The research advances from our collaborative groups as well as other laboratories on the antimutagenesis and anticarcinogenesis effects of tea and tea polyphenolic components are summarized in this chapter.