Tea and cancer prevention: studies in animals and humans.
The role of tea in protection against cancer has been supported by ample evidence from studies in cell culture and animal models. However, epidemiological studies have generated inconsistent results, some of which associated tea with reduced risk of cancer, whereas others found that tea lacks protective activity against certain human cancers. These results raise questions about the actual role of tea in human cancer that needs to be addressed. This article is intended to provide a better perspective on this controversy by summarizing the laboratory studies in animals and humans with emphasis on animal tumor bioassays on skin, lung, mammary glands and colon, and the molecular and cellular mechanisms affected by tea. Finally, a recent small pilot intervention study with green tea in smokers is presented.
Chung
Fung-Lung
FL
American Health Foundation Cancer Center, Institute for Cancer Prevention, Valhalla, NY 10595, USA. chungahf@aol.com
Schwartz
Joel
J
Herzog
Christopher R
CR
Yang
Yang-Ming
YM
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002110:Caffeine / Q000008:administration & dosage; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives*; D002986:Clinical Trials as Topic; D005419:Flavonoids / Q000008:administration & dosage; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology / Q000517:prevention & control; D051379:Mice; D009062:Mouth Neoplasms / Q000209:etiology / Q000473:pathology / Q000517:prevention & control; D009369:Neoplasms / Q000517:prevention & control*; D010636:Phenols / Q000008:administration & dosage; D059808:Polyphenols; D051381:Rats; D012907:Smoking / Q000009:adverse effects; D013662:Tea / Q000737:chemistry
D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D013662:Tea; D002110:Caffeine; D002392:Catechin; C045651:epigallocatechin gallate