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Title Low level Evidence about Tea Consumption and Oral Cancer Incidence
Clinical Question In adults, aged 18-65, does high consumption of a caffeinated drink (1 or more cups a day) such as tea result in higher or lower oral cancer incidence?
Clinical Bottom Line Research on consumption of caffeinated drinks such as tea has shown inconclusive results as to whether tea affects oral cancer incidence; more research is needed.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 14519824Lambert/2003Populations from Shanghai, Miyagi, NetherlandsSystematic Review
Key resultsThis systematic review examined the proposed health benefits and effectiveness of tea as a cancer preventive agent. The review encouraged future intervention studies, as the current research has demonstrated inconclusive results, to examine the bioavailability of tea constituents, such as polyphenols (epicatechin, epigallocatechin, epicatechin-3-gallate, etc.), as well as their mechanism of action within the oral cavity.
#2) 19002670Yang/2008Populations from China and JapanSystematic Review
Key resultsIn animal models, the antioxidative and anti-carcinogenic activities of tea polyphenols have been clearly demonstrated in oral, esophageal, stomach, intestinal, colon, skin, liver, bladder, prostate, and breast cancer, but have not been consistently observed in human studies.
#3) 19588362Boehm/200951 Studies, more than 1.6 million participants (majority from Asia).Systematic Review
Key resultsGreen tea consumption was 3 to 5 cups per day (up to 1200 mL/day) with a minimum of 250 mg/day of catechins (a type of polyphenol found within tea). The results of these studies demonstrated insufficient and conflicting evidence relating tea consumption to cancer prevention whether esophageal, gastric, colon, rectum, oral, or pancreatic cancer.
Evidence Search “Tea and Incidence of Oral Cancer” using Systematic Reviews as a filter
Comments on
The Evidence
The evidence presented in these studies appears valid through animal models and has demonstrated the potential value of tea consumption for purposes of its anti-oxidant nature and potential to reduce cancer risk. However, more research is required to apply towards human models and to elucidate the possible cancer preventive mechanisms of tea polyphenols.
Applicability The evidence presented in these studies is low level at this time because despite many of the animal studies involving rats showing positive results in reducing carcinogenesis, the studies have yet to demonstrate the mechanism of action of certain polyphenols within tea in reducing carcinogenesis in human populations.
Specialty/Discipline (Public Health) (General Dentistry) (Dental Hygiene)
Keywords Oral cancer, Tea
ID# 2491
Date of submission: 07/11/2013spacer
E-mail louiec@ohsu.edu
Author Christopher Alex Louie
Co-author(s) e-mail
Faculty mentor/Co-author Ronald Sakaguchi, DDS, MS, PhD, MBA & Eli Schwarz, DDS, MPH, PhD
Faculty mentor/Co-author e-mail sakaguch@ohsu.edu; schwarz@ohsu.edu
Basic Science Rationale
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