Effect of green tea and Tai Chi on bone health in postmenopausal osteopenic women: a 6-month randomized placebo-controlled trial

Abstract

Postmenopausal women with osteopenia received green tea polyphenols (GTP) supplement and/or Tai Chi exercise for 6 months. Bone turnover biomarkers, calcium metabolism, and muscle strength were measured. This study showed that GTP supplementation and Tai Chi exercise increased bone formation biomarkers and improved bone turnover rate. Tai Chi exercise increased serum parathyroid hormone. GTP supplementation, Tai Chi exercise, and the combination of the two all improved muscle strength in postmenopausal women with osteopenia.

Introduction: This study evaluated the effect of GTP supplementation and Tai Chi (TC) exercise on serum markers of bone turnover (bone-specific alkaline phosphatase, BAP, and tartrate-resistant acid phosphatase, TRAP), calcium metabolism, and muscle strength in postmenopausal osteopenic women.

Methods: One hundred and seventy-one postmenopausal osteopenic women were randomly assigned to four groups: (1) placebo (500 mg starch/day), (2) GTP (500 mg GTP/day), (3) placebo + TC (placebo plus TC training at 60 min/session, three sessions/week), and (4) GTP + TC (GTP plus TC training). Overnight fasting blood and urine samples were collected at baseline, 1, 3, and 6 months for biomarker analyses. Muscle strength was evaluated at baseline, 3, and 6 months. One hundred and fifty subjects completed the 6-month study.

Results: Significant increases in BAP level due to GTP intake (at 1 month) and TC (at 3 months) were observed. Significant increases in the change of BAP/TRAP ratio due to GTP (at 3 months) and TC (at 6 months) were also observed. Significant main effect of TC on the elevation in serum parathyroid hormone level was observed at 1 and 3 months. At 6 months, muscle strength significantly improved due to GTP, TC, and GTP + TC interventions. Neither GTP nor TC affected serum TRAP, serum and urinary calcium, and inorganic phosphate.

Conclusion: In summary, GTP supplementation and TC exercise increased BAP and improved BAP/TRAP ratio. TC exercise increased serum parathyroid hormone. GTP supplementation, TC exercise, and the combination of the two all improved muscle strength in postmenopausal women with osteopenia.

Trial registration: ClinicalTrials.gov NCT00625391.

Conflict of interest statement

Conflicts of interest None.

Figures

Fig. 1

Study flow chart

Fig. 2

Change of BAP/TRAP ratio (±SEM) relative to baseline. Asterisk indicates significant main effect of GTP intake on change in BAP/TRAP ratio after 3 months (p<0.05). Plus sign indicates significant main effect of TC exercise on change in BAP/TRAP ratio after 6 months (p<0.05)

Fig. 3

Change of serum intact PTH (±SEM) relative to baseline. Plus sign indicates significant main effect of TC exercise on change in serum intact PTH at 1 and 3 months (p<0.05)

Fig. 4

Effects of GTP supplementation and TC exercise on muscle strength (static leg strength/endurance evaluated by wall-sit test) in postmenopausal osteopenic women. Data are mean±SEM. Asterisk indicates significant difference from baseline (month 0) for each treatment group (p<0.001 for the GTP group, p<0.001 for Placebo + TC group, and p=0.001 for GTP + TC group)