Green tea extract and catechol-O-methyltransferase genotype modify the post-prandial serum insulin response in a randomised trial of overweight and obese post-menopausal women.
Green tea extract (GTE) may be involved in a favourable post-prandial response to high-carbohydrate meals. The catechol-O-methyltransferase (COMT) genotype may modify these effects. We examined the acute effects of GTE supplementation on the post-prandial response to a high-carbohydrate meal by assessing appetite-associated hormones and glucose homeostasis marker concentrations in women who consumed 843 mg of (-)-epigallocatechin-3-gallate (EGCG) or placebo capsules for 11-12 months.



Sixty Caucasian post-menopausal women (body mass index ≥ 25.0 kg m-2) were included in a randomised, double-blind feeding study. GTE was consumed with a breakfast meal [2784.0 kJ (665.4 kcal); 67.2% carbohydrate]. Blood samples were drawn pre-meal, post-meal, and every 30 min for 4 h. Participants completed six satiety questionnaires.



Plasma leptin, ghrelin and adiponectin did not differ between GTE and placebo at any time point; COMT genotype did not modify these results. Participants randomised to GTE with the high-activity form of COMT (GTE-high COMT) had higher insulin concentrations at time 0, 0.5 and 1.0 h post-meal compared to all COMT groups randomised to placebo. Insulin remained higher in the GTE-high COMT group at 1.5, 2.0 and 2.5 h compared to Placebo-low COMT (P < 0.02). GTE-high COMT had higher insulin concentrations at times 0, 0.5, 1.0, 1.5 and 2.0 h compared to the GTE-low COMT (P ≤ 0.04). Area under the curve measurements of satiety did not differ between GTE and placebo.



GTE supplementation and COMT genotype did not alter acute post-prandial responses of leptin, ghrelin, adiponectin or satiety, although it may be involved in post-meal insulinaemic response of overweight and obese post-menopausal women.
Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, University of Minnesota, Minneapolis, MN, USA.
A M
AM
Dostal
Department of Nutrition and Dietetics, University of North Florida, Jacksonville, FL, USA.
A
A
Arikawa
Department of Food Science and Nutrition, University of Minnesota, St Paul, MN, USA.
L
L
Espejo
Department of Food Science and Nutrition, University of Minnesota, St Paul, MN, USA.
S
S
Bedell
Department of Food Science and Nutrition, University of Minnesota, St Paul, MN, USA.
M S
MS
Kurzer
Department of Nutrition, Exercise, and Health Sciences, Central Washington University, Ellensburg, WA, USA.
N R
NR
Stendell-Hollis
D052242:Adiponectin / Q000097:blood; D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage / Q000032:analysis; D015992:Body Mass Index; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005838:Genotype; D054439:Ghrelin / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D050177:Overweight / Q000097:blood*; D010936:Plant Extracts / Q000008:administration & dosage*; D017698:Postmenopause; D019518:Postprandial Period / Q000235:genetics*; D011795:Surveys and Questionnaires; D013662:Tea / Q000737:chemistry
D052242:Adiponectin; D000975:Antioxidants; D054439:Ghrelin; D007328:Insulin; D020738:Leptin; D010936:Plant Extracts; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate; C588010:COMT protein, human; D002394:Catechol O-Methyltransferase
green tea; insulin sensitivity; obesity; post-menopausal women; post-prandial response; satiety