A study presented at the Digestive Disease Week convention, held in New Orleans in May 2004, has found a mechanism for green tea in inhibiting esophageal cancer associated with Barrett's esophagus. Barrett's esophagus is a precancerous condition which results from chronic irritation of the esophagus that occurs with gastroesophageal reflux disorder. Tea drinking has been linked with a lower risk of several cancers of the gastrointestinal tract, and the esophagus may be exposed to high levels of green tea polyphenols, such as epigallocatechin gallate (EGCG), when green tea is consumed.
Howard Y Chang, MD and colleagues at Harvard Medical School and the Veterans Administration Boston Healthcare System administered varying concentrations of EGCG to cultured human Barrett's esophagus-associated adenocarcinoma cells and compared them to untreated cells. They found that cell growth was inhibited in a dose dependent manner within 72 hours of exposure to EGCG. The team concluded that EGCG induces the programmed cell death known as apoptosis, which occurred as early as 24 hours in the cells exposed to the compound. Further research found an elevation of caspase 3 (an enzyme involved in apoptosis) in the treated cells compared to untreated cells, as well as increased cleaved PARP protein levels, another indicator of apoptosis.
Dr Chang summarized, "Research suggests that drinking green tea may be both a valuable chemopreventive therapy as well as a treatment for esophageal adenocarcinoma. Our results suggest that extracts in green tea may help to lower the prevalence of esophageal adenocarcinoma, one of the fastest growing cancers in western countries."
Howard Y. Chang, Mihir S. Wagh, Masood A. Shammas, Hemanta Koley, Raj K. Goyal. Mechanism of cell growth inhibition by green tea extract in Barrett's associated esophageal adenocarcinoma. Harvard Medical School and VA Boston Healthcare System.