A 3-day EGCG-supplementation reduces interstitial lactate concentration in skeletal muscle of overweight subjects

Jasper Most,Igor Bendik,Jeannette J Hospers,Jan-Willem Van Dijk,Gijs H Goossens,Judith G P Van Can,Johan Jocken,Ellen E Blaak

doi:10.1038/srep17896

Jasper Most, Igor Bendik + Show 6 more

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https://doi.org/10.1038/srep17896

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Journal: Scientific Reports	Publication Date: Dec 9, 2015
Citations: 22	License type: CC BY 4.0

Affiliation: Maastricht University Medical Centre

Abstract

Green tea, particularly epigallocatechin-3-gallate (EGCG), may affect body weight and composition, possibly by enhancing fat oxidation. The aim of this double-blind, randomized placebo-controlled cross-over study was to investigate whether 3-day supplementation with EGCG (282mg/day) stimulates fat oxidation and lipolysis in 24 overweight subjects (age = 30 ± 2yrs, BMI = 27.7 ± 0.3 kg/m2). Energy expenditure, substrate metabolism and circulating metabolites were determined during fasting and postprandial conditions. After 6 h, a fat biopsy was collected to examine gene expression. In 12 subjects, skeletal muscle glycerol, glucose and lactate concentrations were determined using microdialysis. EGCG-supplementation did not alter energy expenditure and substrate oxidation compared to placebo. Although EGCG reduced postprandial circulating glycerol concentrations (P = 0.015), no difference in skeletal muscle lipolysis was observed. Fasting (P = 0.001) and postprandial (P = 0.003) skeletal muscle lactate concentrations were reduced after EGCG-supplementation compared to placebo, despite similar tissue blood flow. Adipose tissue leptin (P = 0.05) and FAT/CD36 expression (P = 0.08) were increased after EGCG compared to placebo. In conclusion, 3-day EGCG-supplementation decreased postprandial plasma glycerol concentrations, but had no significant effects on skeletal muscle lipolysis and whole-body fat oxidation in overweight individuals. Furthermore, EGCG decreased skeletal muscle lactate concentrations, which suggest a shift towards a more oxidative muscle phenotype.

Highlights

Concentrations after an oral glucose tolerance test[22], most studies found no short-term effect on glucose homeostasis in humans[16,23,24]
This study was designed to study the acute effects of EGCG supplementation (282 mg/day), the main catechin of green tea, on whole-body and skeletal muscle lipolysis and whole-body fat oxidation in overweight subjects
Supplementation of 282 mg/day EGCG for 3 days decreased circulating glycerol and tended to reduce free fatty acids (FFA) concentrations but did not alter local muscle lipolysis, substrate oxidation and energy expenditure compared to placebo

Summary

Introduction

Concentrations after an oral glucose tolerance test[22], most studies found no short-term effect on glucose homeostasis in humans[16,23,24]. Green tea extract reduced malonyl-CoA in skeletal muscle, which is an inhibitor of carnitine palmitoyl transferase (CPT), an enzyme involved in fatty acid transportation into the mitochondria[30]. The latter studies in mice, as well as our recent human study showing that combined EGCG and resveratrol supplementation affects flexibility of postprandial substrate oxidation without changes in systemic lipolysis[19] may suggest that skeletal muscle is a major target tissue for the EGCG-induced metabolic effects.

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