Green Tea and Tai Chi for Postmenopausal Osteopenic Women
Chwan-Li Shen (Texas Tech University Health Sciences Center)
Ming-Chien Chyu (Texas Tech University)
Barbara C Pence (Texas Tech University Health Sciences Center)
James K Yeh (Winthrop-University Hospital, Mineola, NY)
Yan Zhang (Texas Tech University Health Sciences Center)
Carol K Felton (Texas Tech University Health Sciences Center)
Susan Doctolero (Texas Tech University Health Sciences Center)
Jia-Sheng Wang (University of Georgia, Athens, GA)
December 27, 2010
- In a recent comprehensive review, we suggest that tea, particularly green tea,
and its bioactive components might reduce bone fracture risk by benefiting bone
mineral density (BMD) and supporting osteoblastic activities while suppressing
osteoclastic activities, possibly due to their antioxidant and/or
anti-inflammatory functions. However, limited information is available on the
protective effect of consumption of tea or its bioactive components (e.g., GTP)
on bone health in postmenopausal women. On the other hand, Tai Chi (TC), a form
of mind-body, moderate-intensity, aerobic and muscular fitness exercise, has
also shown to potentially benefit bone health. However, there is limited
information based on systematic study of TC’s effect on bone health in
postmenopausal women with low bone mass.
Therefore, the long-term goal of the
study is to investigate the effect of GTP and TC exercise on bone health in the
targeted population. This paper focuses on the safety and impact on quality of
life associated with this combined intervention. Results of bone, inflammation
and oxidative stress parameters will be reported in a separate paper.
It is important to assess safety issues in conducting a
long-term clinical study involving green tea extract as a treatment. However,
most of the published green tea clinical studies were either short-term (less
than 12-week long), with a longer study period but little or limited information
on safety data related to liver function, or relatively small sample sizes. The
detailed safety information is important because for all of the interest in
clinical studies using green tea as study agents, lacking such information
hinders the research development. The present work is the first GTP safety
report on liver and kidney functions based on a larger sample size in a 24-week
placebo-controlled and randomized clinical trial.
Tai Chi has been investigated in many clinical studies, and is generally
considered a safe intervention/treatment in population with various health
issues. However, no study evaluated the effect of TC in conjunction with GTP
supplementation on liver and kidney function in any study population. It is not
clear if Tai Chi exercise would interact with GTP to attenuate green tea related
toxicity in our study subjects. Such safety data are important to future
clinical studies using GTP and/or Tai Chi as study treatment.
Therefore, the objective of this
paper is to evaluate the safety of 24 weeks of GTP supplementation combined with
TC exercise in postmenopausal osteopenic women. In addition to safety, the
effects of treatment arms on quality of life (as assessed by SF-36
questionnaires) are also reported.
In this study,
171 postmenopausal women with osteopenia were randomly assigned to
4 treatment arms for 24 weeks: (1) Placebo (500 mg starch/day), (2) GTP (500 mg
GTP/day), (3) Placebo + TC (placebo plus TC training at 60 min/session, 3
sessions/week), and (4) GTP + TC (GTP plus TC training).
Among the 171 participants, 150 of them completed the study (12%
attrition rate). The compliance rates for study agents and TC exercise were 89%
and 83%, respectively. Neither GTP supplementation nor TC exercise affected
liver or kidney function parameters throughout the study. No adverse event due
to study treatment was reported by the participants. TC exercise significantly
improved the scores for role-emotional and mental health of subjects, while no
effect on quality of life was observed due to GTP supplementation.
The researchers came to the conclusion that GTP at a dose of 500
mg/day and/or TC exercise at 3 hr/week for 24 weeks appear to be safe in
postmenopausal osteopenic women, particularly in terms of liver and kidney
functions. TC exercise for 24 weeks (3 hr/wk) significantly improved quality of
life in terms of role-emotional and mental health in these subjects.
This study is published by
BMC Complementary and Alternative Medicine
in its December 2010 issue.