Editorial
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World J Gastroenterol. Jun 28, 2013; 19(24): 3713-3722
Published online Jun 28, 2013. doi: 10.3748/wjg.v19.i24.3713
Green tea and the risk of gastric cancer: Epidemiological evidence
I-Chun Hou, Saral Amarnani, Mok T Chong, Anupam Bishayee
I-Chun Hou, Saral Amarnani, Department of Clinical Research, American University of Health Sciences, Signal Hill, CA 90755, United States
Mok T Chong, Department of Pharmacy Practice, School of Pharmacy, American University of Health Sciences, Signal Hill, CA 90755, United States
Anupam Bishayee, Department of Pharmaceutical Sciences, School of Pharmacy, American University of Health Sciences, Signal Hill, CA 90755, United States
Author contributions: Hou IC performed literature search and collection as well as drafted the manuscript; Bishayee A performed additional bibliographic work as well as revised and edited the final manuscript; Amarnani S and Chong MT assisted Hou IC to write the first draft and reviewed the manuscript with constructive criticism.
Correspondence to: Anupam Bishayee, PhD, Department of Pharmaceutical Sciences, School of Pharmacy, American University of Health Sciences, 1600 East Hill Street, Signal Hill, CA 90755, United States. abishayee@auhs.edu
Telephone: +1-562-9882278 Fax: +1-562-9881791
Received: January 10, 2013
Revised: April 14, 2013
Accepted: May 9, 2013
Published online: June 28, 2013
Processing time: 169 Days and 10.4 Hours
Abstract

Gastric cancer (GC) is one of the leading causes of cancer death in the world. Numerous efforts are being made to find chemoprotective agents able to reduce its risk. Amongst these, green tea has been reported to have a protective effect against stomach cancer. This article aims to critically evaluate all epidemiological studies reporting an association between green tea consumption and GC risk. MEDLINE, EBSCOHOST and Google Scholar were used to search for clinical trials of green tea and its correlation to stomach cancer. Studies include cohort and case-control studies. Outcome of interests are inverse association, no association, and positive association. Seventeen epidemiologic studies were reviewed. Eleven studies were conducted in Japan, five in China, and one with Japanese descendent in Hawaii. Ten case-control studies and seven cohort studies were included. The relative risks or odds ratio of GC for the highest level of green tea consumption was compared. Seven studies suggested no association, eight an inverse association, and one a positive association. One study had shown a significantly lowered GC risk when tea was served warm to cold. Another study also showed a significantly risk with lukewarm tea. All studies that analyzed men and women separately have suggested a reduced risk in women than in men, albeit no significant difference. This review demonstrates that there is insufficient information to support green tea consumption reduces the risk of GC. More studies on the subject matter are warranted.

Keywords: Gastric cancer; Green tea; Epidemiology; Case-control study; Cohort study

Core tip: Gastric cancer (GC) is one of the leading causes of cancer death in the world. Numerous efforts are being made to find chemoprotective agents able to reduce its risk. This review demonstrates that there is insufficient information to support green tea consumption reduces the risk of GC. More studies on the subject matter are warranted.