Short-term green tea extract supplementation attenuates the postprandial blood glucose and insulin response following exercise in overweight men.
Green tea extract (GTE) ingestion improves glucose homeostasis in healthy and diabetic humans, but the interactive effect of GTE and exercise is unknown. The present study examined the effect of short-term GTE supplementation on the glycemic response to an oral glucose load at rest and following an acute bout of exercise, as well as substrate oxidation during exercise. Eleven sedentary, overweight men with fasting plasma glucose (FPG) ≥5.6 mmol·L-1(age, 34 ± 13 years; body mass index = 32 ± 5 kg·m-2; FPG = 6.8 ± 1.0; mean ± SD) ingested GTE (3× per day, 1050 mg·day-1total) or placebo (PLA) for 7 days in a double-blind, crossover design. The effects of a 75-g glucose drink were assessed on 4 occasions during both GTE and PLA treatments: On days 1 and 5 at rest, and again following an acute bout of exercise on days 3 and 8. The glycemic response was assessed via an indwelling continuous glucose monitor (CGM) and venous blood draws. At rest, 1-h CGM glucose area under the curve was not different (P > 0.05), but the postexercise response was lower after GTE versus PLA (330 ± 53 and 393 ± 65 mmol·L-1·min-1, main effect of treatment, P < 0.05). The 1-h postprandial peaks in venous blood glucose (8.6 ± 1.6 and 9.8 ± 2.2 mmol·L-1) and insulin (96 ± 59 and 124 ± 68 μIU·ml-1) were also lower postexercise with GTE versus PLA (time × treatment interactions, P < 0.05). In conclusion, short-term GTE supplementation did not affect postprandial glucose at rest; however, GTE was associated with an attenuated glycemic response following a postexercise oral glucose load. These data suggest that GTE might alter skeletal muscle glucose uptake in humans.
Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.|Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.
Brian J
BJ
Martin
Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.|Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.
Martin J
MJ
MacInnis
Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.|Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.
Jenna B
JB
Gillen
Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.|Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.
Lauren E
LE
Skelly
Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.|Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.
Martin J
MJ
Gibala
catechins; catéchines; exercise metabolism; extrait de thé vert; glucose metabolism; green tea extract; insulin; insuline; métabolisme du glucose; métabolisme à l’effort