The study was conducted in 12 healthy male volunteers aged 28--42 years. Potential volunteers were excluded after initial screening if they reported the use
of any medication or dietary supplements. Further exclusion criteria consisted of a history of major illness,
including heart disease, diabetes mellitus, liver disease
and renal disease, a body mass index (BMI) 430 kg/m2,
alcohol intake averaging 440 g/day, or regular tea or
co¡ee intake averaging 41cup/day. Before the study,
subjects were instructed to avoid drinking tea or other
antioxidant-containing beverages for one week; otherwise they kept to their usual diet and lifestyle. This
study had the approval of the Ethical Committee of the
Asan Medical Center. Written informed consent was
obtained from every volunteer.