Mitigation of Oxidative Damage by Green Tea Polyphenols and Tai Chi Exercise in Postmenopausal Women with Osteopenia

University of Ottawa, Canada
PLoS ONE (Impact Factor: 3.23). 10/2012; 7(10):e48090. DOI: 10.1371/journal.pone.0048090
Source: PubMed


Osteoporosis is a degenerative bone disease predominantly in postmenopausal women. Green tea polyphenols (GTP) and Tai Chi (TC) have been shown to be beneficial on human bone health. This study examined the efficacy of GTP and TC on mitigation of oxidative damage in postmenopausal women with osteopenia.
A 6-month randomized and placebo-controlled clinical trial was conducted in 171 postmenopausal women with osteopenia, who were recruited from Lubbock County, Texas. These participants were treated with placebo, GTP (500 mg daily), placebo + TC (60-minute group exercise, 3 times/week), or GTP (500 mg daily) + TC (60-minute group exercise, 3 times/week), respectively. Their blood and urine samples were collected at the baseline, 1-, 3- and 6-months during intervention for assessing levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), an oxidative DNA damage biomarker, and concentrations of serum and urine GTP components.
The elevated concentrations of serum and urinary GTP components demonstrated a good adherence for the trial. A significant reduction of urinary 8-OHdG concentrations was found in all three treated groups during 3-month (P<0.001) and 6-month (P<0.001) intervention, as compared to the placebo group. The significant time- and dose-effects on mitigation of the oxidative damage biomarker were also found for GTP, TC, and GTP+TC intervened groups.
Our study demonstrated that GTP and TC 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. NCT00625391.

Download full-text


Available from: Lili Tang,
  • Source
    • "Another hypothesis suggests that profound meditation increases levels of the hormone dehydroepiandrosterone, a marker for aging that has been linked with an increase in the activity of antioxidant enzymes. These possibilities, independent of but along with the mechanisms induced by the physical activity directly, allow us to suggest that the practice of Tai Chi promotes an antioxidant response [39–42]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: It has recently been reported that the practice of Tai Chi reduces oxidative stress (OxS), but it is not clear whether walking or Tai Chi produces a greater antioxidant effect. The aim of the present study was to evaluate the effect of the practice of Tai Chi and walking on markers for OxS. We carried out a quasi-experimental study with 106 older adults between 60 and 74 years of age who were clinically healthy and divided into the following groups: (i) control group (n = 23), (ii) walking group (n = 43), and (iii) Tai Chi group (n = 31). We measured the levels of lipoperoxides (LPO), antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx), and total antioxidant status (TAS) pre- and post-intervention in all subjects. The data were subjected to a covariant analysis. We found lower levels of LPO in the Tai Chi group compared with the walking group (Tai Chi, 0.261 ± 0.02; walking, 0.331 ± 0.02; control, 0.304 ± 0.023 µmol/L; P = 0.05). Likewise, we observed significantly higher SOD activity and lower OxS-score in the Tai Chi group (P < 0.05). Our findings suggest that the practice of Tai Chi produces a more effective antioxidant effect than walking.
    Oxidative Medicine and Cellular Longevity 07/2013; 2013(1):298590. DOI:10.1155/2013/298590 · 3.36 Impact Factor
  • Source
    • "In the Physical Activity for Total Health study, there was decreased oxidative damage to lipids as measured by F2-isoprostane levels in exercisers compared to controls, with a more pronounced statistically significant reduction in exercisers who increased their physical fitness by >15 %; this effect occurred independent of obesity status [85]. RCTs of Tai Chi exercise [86] and resistance training [87] also showed reductions in oxidative damage. Yet with respect to telomere length, the NEW trial found no effect of dietary weight loss and/or aerobic exercise [88•], nor did a diet-physical activity lifestyle intervention RCT for diabetes prevention in high-risk adults [89]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Strong and consistent evidence exists that physical activity reduces breast cancer risk by 10-25 %, and several proposed biologic mechanisms have now been investigated in randomized, controlled, exercise intervention trials. Leading hypothesized mechanisms relating to postmenopausal breast cancer include adiposity, endogenous sex hormones, insulin resistance, and chronic low-grade inflammation. In addition, other pathways are emerging as potentially important, including those involving oxidative stress and telomere length, global DNA hypomethylation, immune function, and vitamin D exposure. Recent exercise trials in overweight/obese postmenopausal women implicate weight loss as a mechanism whereby exercise induces favorable changes in circulating estradiol levels and other biomarkers as well. Still it is plausible that some exercise-induced biomarker changes do not require loss of body fat, whereas others depend on abdominal fat loss. We highlight the latest findings from randomized, controlled trials of healthy postmenopausal women, relating exercise to proposed biomarkers for postmenopausal breast cancer risk.
    03/2013; 3(1). DOI:10.1007/s13668-013-0069-8
  • [Show abstract] [Hide abstract]
    ABSTRACT: Osteoporosis is a major health problem in the aging population worldwide. Cross-sectional and retrospective evidence indicates that tea consumption may be a promising approach in mitigating bone loss and in reducing risk of osteoporotic fractures among older adults. Tea polyphenols enhance osteoblastogenesis and suppress osteoclastogenesis in vitro. Animal studies reveal that intake of tea polyphenols have pronounced positive effects on bone as shown by higher bone mass and trabecular bone volume, number, and thickness and lower trabecular separation via increasing bone formation and inhibition of bone resorption, resulting in greater bone strength. These osteoprotective effects appear to be mediated through antioxidant or antiinflammatory pathways along with their downstream signaling mechanisms. A short-term clinical trial of green tea polyphenols has translated the findings from ovariectomized animals to postmenopausal osteopenic women through evaluation of bioavailability, safety, bone turnover markers, muscle strength, and quality of life. For future studies, preclinical animal studies to optimize the dose of tea polyphenols for maximum osteoprotective efficacy and a follow-up short-term dose-response trial in postmenopausal osteopenic women are necessary to inform the design of randomized controlled studies in at-risk populations. Advanced imaging technology should also contribute to determining the effective dose of tea polyphenols in achieving better bone mass, microarchitecture integrity, and bone strength, which are critical steps for translating the putative benefit of tea consumption in osteoporosis management into clinical practice and dietary guidelines.
    American Journal of Clinical Nutrition 10/2013; 98(6). DOI:10.3945/ajcn.113.058255 · 6.77 Impact Factor
Show more