title: Acute ingestion of catechin-rich green tea improves postprandial glucose status and increases serum thioredoxin concentrations in postmenopausal women.
abstract: Elevated postprandial hyperglycaemia and oxidative stress increase the risks of type 2 diabetes and CVD. Green tea catechin possesses antidiabetic properties and antioxidant capacity. In the present study, we examined the acute and continuous effects of ingestion of catechin-rich green tea on postprandial hyperglycaemia and oxidative stress in healthy postmenopausal women. Participants were randomly assigned into the placebo (P, n 11) or green tea (GT, n 11) group. The GT group consumed a catechin-rich green tea (catechins 615 mg/350 ml) beverage per d for 4 weeks. The P group consumed a placebo (catechins 92 mg/350 ml) beverage per d for 4 weeks. At baseline and after 4 weeks, participants of each group consumed their designated beverages with breakfast and consumed lunch 3 h after breakfast. Venous blood samples were collected in the fasted state (0 h) and at 2, 4 and 6 h after breakfast. Postprandial glucose concentrations were 3 % lower in the GT group than in the P group (three-factor ANOVA, group × time interaction, P< 0·05). Serum concentrations of the derivatives of reactive oxygen metabolites increased after meals (P< 0·05), but no effect of catechin-rich green tea intake was observed. Conversely, serum postprandial thioredoxin concentrations were 5 % higher in the GT group than in the P group (three-factor ANOVA, group × time interaction, P< 0·05). These findings indicate that an acute ingestion of catechin-rich green tea has beneficial effects on postprandial glucose and redox homeostasis in postmenopausal women.
authors.affiliation: Faculty of Sport Sciences, Waseda University,2-579-15 Mikajima,Tokorozawa,Saitama359-1192,Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Health and Sports Sciences,Faculty of Education, Tokyo Gakugei University,4-1-1 Nukuikitamachi,Koganei,Tokyo184-8501,Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Miyashita
authors.affiliation: Faculty of Sport Sciences, Waseda University,2-579-15 Mikajima,Tokorozawa,Saitama359-1192,Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Graduate School of Sport Sciences, Waseda University,2-579-15 Mikajima,Tokorozawa,Saitama359-1192,Japan.
authors.forename: Seong-Ryu
authors.initials: SR
authors.lastname: Bae
authors.affiliation: Graduate School of Sport Sciences, Waseda University,2-579-15 Mikajima,Tokorozawa,Saitama359-1192,Japan.
authors.forename: Hyeon-Ki
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Health Care Food Research, Kao Corporation,2-1-3,Bunka Sumida-ku,Tokyo131-8501,Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Wakisaka
authors.affiliation: Health Care Food Research, Kao Corporation,2-1-3,Bunka Sumida-ku,Tokyo131-8501,Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Matsui
authors.affiliation: Health Care Food Research, Kao Corporation,2-1-3,Bunka Sumida-ku,Tokyo131-8501,Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Takeshita
authors.affiliation: Health Care Food Research, Kao Corporation,2-1-3,Bunka Sumida-ku,Tokyo131-8501,Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Yasunaga
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D002392:Catechin / Q000008:administration & dosage*; D004311:Double-Blind Method; D015444:Exercise; D005215:Fasting; D005260:Female; D006801:Humans; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects; D010919:Placebos; D017698:Postmenopause / Q000097:blood*; D019518:Postprandial Period; D017382:Reactive Oxygen Species / Q000097:blood; D013662:Tea; D013879:Thioredoxins / Q000097:blood*
chemical_list: D001786:Blood Glucose; D010919:Placebos; D017382:Reactive Oxygen Species; D013662:Tea; D013879:Thioredoxins; D002392:Catechin