Does green tea affect postprandial glucose, insulin and satiety in healthy subjects: a randomized controlled trial

Julija Josic,Jennie Wickeberg,Anna Tholén Olsson,Joanna Hlebowicz,Sandra Lindstedt

doi:10.1186/1475-2891-9-63

Julija Josic, Jennie Wickeberg + Show 3 more

Open Access

https://doi.org/10.1186/1475-2891-9-63

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Journal: Nutrition journal	Publication Date: Nov 30, 2010
Citations: 114	License type: cc-by

Affiliation: Skåne University Hospital, Lund University

Abstract

BackgroundResults of epidemiological studies have suggested that consumption of green tea could lower the risk of type 2 diabetes. Intervention studies show that green tea may decrease blood glucose levels, and also increase satiety. This study was conducted to examine the postprandial effects of green tea on glucose levels, glycemic index, insulin levels and satiety in healthy individuals after the consumption of a meal including green tea.MethodsThe study was conducted on 14 healthy volunteers, with a crossover design. Participants were randomized to either 300 ml of green tea or water. This was consumed together with a breakfast consisting of white bread and sliced turkey. Blood samples were drawn at 0, 15, 30, 45, 60, 90, and 120 minutes. Participants completed several different satiety score scales at the same times.ResultsPlasma glucose levels were higher 120 min after ingestion of the meal with green tea than after the ingestion of the meal with water. No significant differences were found in serum insulin levels, or the area under the curve for glucose or insulin. Subjects reported significantly higher satiety, having a less strong desire to eat their favorite food and finding it less pleasant to eat another mouthful of the same food after drinking green tea compared to water.ConclusionsGreen tea showed no glucose or insulin-lowering effect. However, increased satiety and fullness were reported by the participants after the consumption of green tea.Trial registration numberNCT01086189

Highlights

Results of epidemiological studies have suggested that consumption of green tea could lower the risk of type 2 diabetes
No significant differences were seen in the areas under the plasma glucose curves (Table 1)
No significant differences in serum insulin levels or insulin area under the curve (AUC) were observed between the green tea meal and the reference meal during the 120 min postprandial observation period (Figure 2 and Table 1)

Summary

Introduction

Results of epidemiological studies have suggested that consumption of green tea could lower the risk of type 2 diabetes. This study was conducted to examine the postprandial effects of green tea on glucose levels, glycemic index, insulin levels and satiety in healthy individuals after the consumption of a meal including green tea. The focus of many previous studies on green tea has been on the anti-oxidative properties of catechins, and their potential role in controlled studies investigating the effect of green tea on glucose metabolism have been performed in humans, with varying results. A crossover trial demonstrated that two months’ supplementation with GTE significantly lowered HbA1c in individuals with glucose abnormalities [8]. A crossover study performed on healthy human participants showed that green tea lowered glucose levels after OGTT [10]. Neither GTE nor EGCG was found to have any effect on fasting glucose, insulin sensitivity or glucose levels after OGTT [11,12,13]

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