Summary

This study is looking at the potential benefits of drinking green tea and black tea. The association between consuming green tea and black tea and its effects on oxidative stress will be evaluated. For a detailed summary, click here.

Participation

We expect to screen 450 subjects in order to enroll at least 195 subjects. We are also expecting that at least 150 subjects will complete the intervention trial.

Eligibility Requirements

• Smokers and Former Smokers, between the ages of 40-80 years of age and a smoking history of > 25 pack-years
  
• Not be pregnant or intending to get pregnant during the study period (women participants).
  
• Subjects who regularly consume less than 6 cups of tea per week.
  
• All subjects must have pre-study requirements performed before initiation of treatment.
  
• Subjects cannot take mega-doses of vitamins during the trial. Such vitamin therapy must be discontinued at least 2 weeks prior to study entry.
  
• Must be willing to refrain from consuming tea or tea products starting two weeks before the placebo run-in period and for the entire study period (a total of eight months).
  
• Must be willing to refrain from the use of dietary supplements or herbal products (e.g., herbal tea, melatonin, echinacea, St. John's wort, and DHEA) starting two weeks before the placebo run-in period and for the entire study period (a total of eight months).
  
• Must be willing not to participate in other clinical trials while participating in this trial
  
• Make a 8-month commitment to the study.
  
• Must sign the informed consent approved by the University of Arizona Human Subjects Committee.
  

Exclusion Criteria

• Subjects immunosuppressed by virtue of medication or disease.
  
• Serious concurrent illness that could interfere with study regimen.
  
• Subjects with a history of invasive cancer (including melanoma), or systemic chemotherapy, within the past 5 years
  
• Subjects who cannot or unwilling to consume caffeinated beverages.