Neural Effects of Green Tea Extract on Dorsolateral Prefrontal Cortex

Green tea is being recognized as a beverage with potential benefits for human health and on cognitive function. In vitro and in vivo studies provide preliminary evidence that green tea intake may play a positive role in improving effects on cognitive functions. The investigators aim to examine the neural effects of green tea extract on brain activation in humans.

Study Overview

• Status: Completed
• Conditions: Exploratory Behavior
• Intervention / Treatment: Dietary supplement: Single intragastric instillation of 250 ml green tea extract; Dietary supplement: Single intragastric instillation of 500 ml green tea extract; Dietary supplement: Single intragastric instillation of 250 ml control solution; Dietary supplement: Single intragastric instillation of 500 ml control solution

Detailed Description

As functional neuroimaging provides a means of examining how green tea extract acts on the brain, we used functional magnetic resonance imaging (fMRI) to study healthy volunteers while they performed a working memory task following intra-gastric administration of either 250 ml or 500 ml Rivella green® (RG), a milk whey based green tea extract containing soft drink, or Rivella blue® (RB), a milk whey based soft drink without green tea extract as sham condition in a double-blind, controlled design. Based on the literature on pharmacological and behavioural effects of green tea, we hypothesized - a priori - that green tea extract would subtly modulate the engagement of the dorsolateral prefrontal cortex (DLPFC), a brain region critically involved in many cognitive functions such as working memory processing.

A double-blind, controlled, within-subject study with counterbalanced order of substance administration using an established protocol (6-8) was conducted over 4 sessions (250 ml or 500 ml Rivella green® (including green tea extract; RG), 250 or 500 ml Rivella blue® (RB). Each participant was scanned four times with a one-week interval between scans. The order of substance administration across sessions was counterbalanced across subjects, such that equal numbers followed each substance sequence.

• Study Type: Interventional
• Enrollment (Actual): 12
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Basel, Switzerland, CH-4031
    • University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Male

Description

Inclusion Criteria:

• right-handed healthy males, no drugs, non-smoking

Exclusion Criteria:

• drug abuse, smoker, left-handed

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Green tea extract, 250 ml; Single intragastric instillation of 250 ml green tea extract	Dietary supplement: Single intragastric instillation of 250 ml green tea extract; Intragastric instillation by feeding tube
Active Comparator: Green tea extract, 500 ml; Intragastric instillation of 500 ml green tea extract solution	Dietary supplement: Single intragastric instillation of 500 ml green tea extract; Intragastric instillation by feeding tube
Placebo Comparator: Control solution, 250 ml; Intragastric instillation of 250 ml control solution	Dietary supplement: Single intragastric instillation of 250 ml control solution; Intragastric instillation by feeding tube
Placebo Comparator: Control solution, 500 ml; Single intragastric instillation of 500 ml control solution	Dietary supplement: Single intragastric instillation of 500 ml control solution; Intragastric instillation by feeding tube

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional magnetic resonance imaging (fMRI) in healthy volunteers while they performed a working memory task	Whole brain analysis with a cluster-level threshold was followed by an a priori defined region of interest analysis of the dorsolateral prefrontal cortex including a cluster-level threshold and family-wise error adjustment for multiple comparisons.	0 and 45 min

Collaborators and Investigators

• Sponsor: University Hospital, Basel, Switzerland
• Investigators: Principal Investigator: Christoph Beglinger, MD, University Hospital, Basel, Switzerland

Study record dates

Study Major Dates

• Study Start: July 1, 2010
• Primary Completion (Actual): January 1, 2011
• Study Completion (Actual): January 1, 2012

Study Registration Dates

• First Submitted: June 5, 2012
• First Submitted That Met QC Criteria: June 7, 2012
• First Posted (Estimate): June 8, 2012

Study Record Updates

• Last Update Posted (Estimate): June 8, 2012
• Last Update Submitted That Met QC Criteria: June 7, 2012
• Last Verified: June 1, 2012

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pharmaceutical Solutions
• Other Study ID Numbers: EKBB 32/09