Table 3.

Epidemiological studies of the relationship between green tea consumption and human cancer risk.

Organ Sites	Green Tea Consumption Level	Country of the Study Conducted	Gender	Population Size	Results Found	References
Breast	≥5 cups/day ≤4 cups/day	Japan	Men and women	8552	High consumption level showed lower risk	[36]
Lung	n/a	China	Women	675	Consumption of green tea associated with reduced lung cancer risk	[32,49]
Colon-rectum	>5 cups/day	China	Men and women	>60,000	Insignificant increase in risk of colon cancer in regular drinkers than non-drinkers.	[47]
Prostate	≥5 cups/day ≤1 cup/day	Japan	Men	49,920	Green tea consumption may be associated with a reduced risk of prostate cancer	[47,82]
Stomach	≥5 cups/day ≥7 cups/day	Japan	Men	39,290	Greater consumption showed better result	[83]
Liver	≥5 cups/day 1 cup/day	Japan	Men and women	21,128	Greater intake possessed lesser risk	[44]
Skin	n/a				No dose-related result was found
Pancreas	≥7 cups/day <1 cup/day	Japan	Men and women	100,000	No association between green tea consumption and cancer risk was found	[3]
Oral	≥5 cups/day ≤1 cup/day	Japan	Men and women	50,221	An inverse relation between green tea consumption and oral cancer	[47,84]
Ovary	≥4 cups/day	Australia	Men and women	2784	Significant reduction in ovary cancer risk with green tea intake	[69]
Bladder	≥5 cups/day	Canada	Men and women	3045	associated with green tea consumption.	[3]
Esophagus	≥300 g/month	China	Men and women	1884	Moderate level of consumption may reduce the risk but drinking tea > 65 °C has association with increased cancer risk	[81]