WASHINGTONForget those smoke-filled cocktail lounges, tobacco
addicts, and head for a local tea room. Drinking tea after
smoking reduces levels of oxidative stress, reported James E.
Klaunig, PhD, professor of pharmacology and toxicology, Indiana
University School of Medicine. Oxidative stress has been linked to
cancer and other diseases .
What Causes Oxidative Stress?
Oxidative stress may be due to either decreased levels of
There are two sources of the reactive oxygen species that result in
Tobacco smoke is a known source of reactive oxygen species that can
Dr. Klaunig spoke at the Second International Scientific Symposium on
Tea and Human Health, cosponsored by the American Health Foundation,
the American Cancer Society, the Nutrition Committee of the American
Heart Association, and the Tea Council of the USA.
Along with his colleagues J. Chen and C. Han from the Chinese Academy
of Preventive Medicine, Beijing, Dr. Klaunig set out to study, in
smokers, the effects of tea drinking on oxidative damage, production
of reactive oxygen species, and modulation of antioxidants.
In the China arm of the study, army recruits drank three cups of
green or black tea a day and were allotted six cigarettes a day to
smoke after meals. After one week, the smokers showed a
dramatic decrease in reactive oxygen species and
oxidative stress, Dr. Klaunig said. Green tea had a greater effect
than black tea.
Back home in Indiana, Dr. Klaunig recruited volunteers aged 25 to 45.
They were either nonsmokers or pack-a-day smokers. The volunteers
quaffed a total of 30 ounces of green tea daily, drinking the tea
four times a day with meals and snacks. Neither diet nor physical
activity was controlled.
Baseline tests of levels of 8-hydroxy-2´-deoxyguanosine and
lipid peroxidation (measures of oxidative stress) showed that smokers
had higher levels of oxidative stress prior to the trials
start. While both smokers and nonsmokers showed a reduction in
oxidative stress parameters during the study, the smokers exhibited a
much greater response to drinking tea.
Using the Syrian Hamster Embryo (SHE) Cell Transformation Assay, Dr.
Klaunig found that components from black and green tea prevented
or reduced carcinogen-induced cell transformation in a