Green tea polyphenols and Tai Chi for bone health: designing a placebo-controlled randomized trial.
BACKGROUND
Osteoporosis is a major health problem in postmenopausal women. Evidence suggests the importance of oxidative stress in bone metabolism and bone loss. Tea consumption may be beneficial to osteoporosis due to its antioxidant capability. However, lack of objective data characterizing tea consumption has hindered the precise evaluation of the association between tea ingestion and bone mineral density in previous questionnaire-based epidemiological studies. On the other hand, although published studies suggest that Tai Chi (TC) exercise can benefit bone health and may reduce oxidative stress, all studies were conducted using a relatively healthy older population, instead of a high-risk one such as osteopenic postmenopausal women. Therefore, this study was designed to test an intervention including green tea polyphenol (GTP) and TC exercise for feasibility, and to quantitatively assess their individual and interactive effects on postmenopausal women with osteopenia.


METHODS
One hundred and forty postmenopausal women with osteopenia (defined as bone mineral density T-score at the spine and/or hip between 1 to 2.5 SD below the reference database) were randomly assigned to 4 treatment arms: (1) placebo group receiving 500 mg medicinal starch daily, (2) GTP group receiving 500 mg of GTP per day, (3) placebo+TC group receiving both placebo treatment and TC training (60-minute group exercise, 3 times per week), and (4) GTP+TC group receiving both GTP and TC training for 24 weeks. The outcome measures were bone formation biomarker (serum bone alkaline phosphatase), bone resorption biomarker (serum tartrate resistant acid phosphatase), and oxidative DNA damage biomarker (urinary 8-hydroxy-2'-deoxyguanosine). All outcome measures were determined at baseline, 4, 12, and 24 weeks. Urinary and serum GTP concentrations were also determined at baseline, 4, 12, and 24 weeks for bioavailability. Liver function was monitored monthly for safety. A model of repeated measurements with random effect error terms was applied. Traditional procedures such as ANCOVA, chi-squared analysis, and regression were used for comparisons.


CONCLUSIONS
We present the rationale, design, and methodology of a placebo-controlled randomized trial to investigate a new complementary and alternative medicine strategy featuring a dietary supplement and a mind-body exercise for alleviating bone loss in osteopenic postmenopausal women.
Shen
Chwan-Li
CL
Department of Pathology, Texas Tech University Health Sciences Center, Lubbock, Texas, USA. leslie.shen@ttuhsc.edu
Chyu
Ming-Chien
MC
Yeh
James K
JK
Felton
Carol K
CK
Xu
Ke T
KT
Pence
Barbara C
BC
Wang
Jia-Sheng
JS
D000368:Aged; D015519:Bone Density / Q000187:drug effects / Q000502:physiology; D001851:Bone Diseases, Metabolic / Q000178:diet therapy / Q000517:prevention & control; D019587:Dietary Supplements; D005081:Exercise Therapy / Q000379:methods; D005260:Female; D005419:Flavonoids / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D008875:Middle Aged; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology; D015663:Osteoporosis, Postmenopausal / Q000178:diet therapy / Q000517:prevention & control; D010636:Phenols / Q000494:pharmacology / Q000627:therapeutic use*; D059808:Polyphenols; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D026302:Tai Ji; D013662:Tea
D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D013662:Tea