Green Tea Anticancer Mechanisms in Smokers

Study Overview
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Brief Summary
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The purpose of this study is to determine whether green tea may lower the risk of certain cancers.

Detailed Description
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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.

Official Title
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Green Tea Anticancer Mechanisms in Smokers

Conditions
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Cancer

Intervention / Treatment
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* Dietary Supplement: Green Tea
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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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)

Ages Eligible for Study
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Minimum Age: 23 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Green Tea<br>4 cups daily of green tea for 6 weeks | Dietary Supplement: Green Tea<br>* Green Tea 4 cups daily<br>|
| Placebo Comparator: No Green Tea<br>4 cups daily of placebo tea for 6 weeks | Other: Placebo<br>* 4 cups placebo tea for 6 weeks<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Antioxidant effects of green tea versus placebo consumption. | Examine antioxidant effects of green tea versus placebo by measuring scavenging of free radicals; tea flavonoids; inflammatory cell secretion; endogenous antioxidant glutathione. | Measured at post treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Non-antioxidant, cancer-relevant effects of green tea consumption | 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. | Measured at pre-treatment and post treatment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Healthy moderately heavy smokers