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Green Tea Anticancer Mechanisms in Smokers

This study has been completed.
Information provided by (Responsible Party):
Philip Diaz, The Ohio State University Identifier:
First received: June 23, 2010
Last updated: April 20, 2015
Last verified: April 2015
The purpose of this study is to determine whether green tea may lower the risk of certain cancers.

Condition Intervention
Cancer Dietary Supplement: Green Tea Other: Placebo

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Participant)
Primary Purpose: Prevention
Official Title: Green Tea Anticancer Mechanisms in Smokers

Resource links provided by NLM:

Further study details as provided by Philip Diaz, The Ohio State University:

Primary Outcome Measures:
  • Antioxidant effects of green tea versus placebo consumption. [ Time Frame: Measured at post treatment ]
    Examine antioxidant effects of green tea versus placebo by measuring scavenging of free radicals; tea flavonoids; inflammatory cell secretion; endogenous antioxidant glutathione.

Secondary Outcome Measures:
  • Non-antioxidant, cancer-relevant effects of green tea consumption [ Time Frame: Measured at pre-treatment and post treatment ]
    Examine non-antioxidant, cancer-relevant effects of green tea by measuring NF-kappaB inducing kinase; phosphorylation of cell signaling agents; tumor necrosis factor gene expression; lysyl oxidase enzyme; blockage of cancer cell proliferation.

Enrollment: 43
Study Start Date: June 2010
Study Completion Date: August 2013
Primary Completion Date: August 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Green Tea
4 cups daily of green tea for 6 weeks
Dietary Supplement: Green Tea
Green Tea 4 cups daily
Placebo Comparator: No Green Tea
4 cups daily of placebo tea for 6 weeks
Other: Placebo
4 cups placebo tea for 6 weeks

Detailed Description:

Green tea contains phytochemicals, especially flavonoids. Phytochemicals are not absolutely required for normal functions, but may confer health benefits such as antioxidant actions. One can live without phytochemicals, but one may live longer and better with them. The phytochemicals in tea have been proposed to inhibit cancer onset via several different mechanisms. An obvious question is: Can anti-cancer actions of green tea be duplicated by black tea, which in the USA, is consumed more than green tea? The question remains unanswered, and will not be addressed by this project since many questions about green tea have not been answered yet. The contents of both type teas overlap in flavonoids, but green tea has more of the agents thought to be most effective. For example, some of the research cited below uses the flavonoid epigallocatechin gallate. Green tea has 5 times more of this flavonoid than black tea.

This study has two purposes. First, a case will be made that green tea may have several anti-cancer mechanisms, but this contention is not well confirmed by human intervention studies. This case will be made by addressing four questions. Second, justification will be given for the choice of mechanisms to be examined in this project's human intervention.


Ages Eligible for Study:   23 Years to 40 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy 23-40 year old males and non-pregnant females, who are moderately heavy smokers (1-1.75 packs/day, > 2 years)

Exclusion Criteria:

  • Habitual tea intake
  • Habitual flavonoid supplementation
  • Soy product intake over twice a week (soy is high in flavonoids).
  • Pulmonary diseases
  • Chronic or acute infection
  • Admission of heavy alcohol intake (> 14 beers or drinks a week)
  • Body mass index (BMI) > 30 (moderately overweight subjects will be taken)
  • Abnormal EKG
  • History of heart or other major health problems (ie arthritis, diabetes).
  • Subjects with slightly high blood pressure will be eligible for the project, but more severe hypertension (>150/100)
  Contacts and Locations
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Please refer to this study by its identifier: NCT01162642

United States, Ohio
The Ohio State University
Columbus, Ohio, United States, 43210
Sponsors and Collaborators
Philip Diaz
Principal Investigator: Philip Diaz, M.D. Ohio State University
  More Information

Responsible Party: Philip Diaz, M.D., The Ohio State University Identifier: NCT01162642     History of Changes
Other Study ID Numbers: 2007C0109
Study First Received: June 23, 2010
Last Updated: April 20, 2015

Keywords provided by Philip Diaz, The Ohio State University:
Healthy moderately heavy smokers processed this record on August 18, 2017