A randomized and placebo-controlled clinical trial published online in October 2012 indicates that green tea and tai chi reduce oxidative stress in post-menopausal women with osteopenia. The National Osteoporosis Foundation reports that 44 million Americans have low bone density (osteopenia) or osteoporosis. It is estimated that one in two women and up to one in four men over the age of 50 will break a bone due to osteoporosis. Furthermore, approximately half of all Americans over age 50 are expected to have osteopenia or osteoporosis by 2020.
The subjects included 171 postmenopausal women with osteopenia. The women were assigned to one of four intervention groups:
500 mg daily of green tea polyphenols
placebo plus 60-minute group exercise, three times per week of tai chi
500 mg daily green tea polyphenols, plus 60-minute group exercise three times weekly of tai chi
Researchers collected blood and urine samples at the beginning of the study and again after one, three and six months. The investigators assessed levels of the oxidative DNA damage biomarker 8-hydroxy-2’-deoxyguanosine, and concentrations of serum and urine green tea polyphenol components.
The investigators found that elevated concentrations of serum and urinary green tea polyphenol components demonstrated a good adherence for the trial. All three intervention groups showed significant reduction of urinary 8-hydroxy-2’-deoxyguanosine concentrations at three and six months compared to the placebo group.
The researchers stated, “Our study demonstrated that green tea polyphenols and tai chi interventions were effective strategies of reducing the levels of oxidative stress, a putative mechanism for osteoporosis in postmenopausal women, and more importantly, working in an additive manner, which holds the potential as alternative tools to improve bone health in this population.”
Qian G, et al. PLoS One. 2012;10:e48090.