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Green Tea Anticancer Mechanisms in Smokers

23 Years
40 Years
Open (Enrolling)

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Trial Information

Green Tea Anticancer Mechanisms in Smokers

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.

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)

Type of Study:


Study Design:

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Single Blind (Subject), Primary Purpose: Prevention

Outcome Measure:

Antioxidant effects of green tea versus placebo consumption.

Outcome Description:

Examine antioxidant effects of green tea versus placebo by measuring scavenging of free radicals; tea flavonoids; inflammatory cell secretion; endogenous antioxidant glutathione.

Outcome Time Frame:

Measured at post treatment

Safety Issue:


Principal Investigator

Philip Diaz, M.D.

Investigator Role:

Principal Investigator

Investigator Affiliation:

Ohio State University


United States: Institutional Review Board

Study ID:




Start Date:

June 2010

Completion Date:

June 2013

Related Keywords:

  • Cancer
  • Healthy moderately heavy smokers



The Ohio State UniversityColumbus, Ohio  43210