Inhabitants of tea producing districts in Japan have a lower mortality from stomach cancer, possibly the result green tea consumption.
In addition to a regular tea drinking, this population consumes green tea all types of products, including candy, gums, bread, shampoo, lotion, toothpaste, etc.
Contrary to the preceding, however to recent studies found no association between green tea consumption and stomach or colon cancer.
Green tea was linked to a reduced risk of oral cancer in northern Italian and a Chinese population, esophageal cancer in Chinese women, gastric cancer in Swedish adolescents, pancreatic cancer in residents of a retirement community in the United States, and colon cancer in retired male self defense official in Japan.
Cohort studies suggest that there is a protective effect of green tea for colon, urinary bladder, stomach, pancreatic and esophageal cancer.
In Japanese survey, an overall protection by green tea was observed, together with slowdown of the increase of cancer incidence with age. The effects were more pronounced when the tea consumption was more than 10 cups/day.
In another Japanese study, consumption of 7 or more cups per day of green tea significantly decreased the risk of cancer of both the stomach and rectum (by 31% and 54% respectively) compared with non-users.
Regular tea drinkers in China experienced a lower incidence of cancer of the colon, rectum, and pancreas compared with non drinkers of tea.
A case control study from Poland reported a significant reduction in risk of pancreatic cancer with increasing lifetime tea consumption.
Increased green tea consumption was closely associated with decreased axillary lymph node metastases among patients who were premenopausal with stage 1 and 11 breast cancer and overall decreased recurrence of stage 1 and 11 breast cancer.
Study of relationship between green tea and cancer
