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The Effects of Caffeine and L-theanine Both Alone and in Combination on Cerebral Blood Flow, Cognition and Mood

NCT00981955 · Status: COMPLETED · Phase: PHASE4 · Type: INTERVENTIONAL · Enrollment: 24

Last updated 2010-07-23

No results posted yet for this study

Summary

Although the beneficial effects of caffeine on cognition and mood have been reported in a number of studies, relatively few studies have looked at the effects of caffeine in combination with other phytonutrients despite the fact that caffeine is seldom consumed in isolation. L-theanine is a naturally occurring amino-acid found in tea, and has been used historically as a relaxing agent (Haskell et al., 2008). Few have assessed the impact of l-theanine on cognition, but of those that have, the most interesting results were obtained when l-theanine was assessed in combination with caffeine (Haskell et al., 2008). It remains unclear what is underlying the reported effects.

Near Infrared Spectroscopy (NIRS) is an emerging neuroimaging technology that is capable of determining changes in cerebral blood flow (CBF) by measuring the optical properties of oxygenated and deoxygenated blood (Bunce et al., 2006). No study to date has used NIRS to assess cerebral blood flow following treatment with either caffeine, l-theanine or a combination of both. It is anticipated that the proposed study will provide some insight into the mechanism of the previously observed effects both alone and in combination.

A randomised, double-blind, placebo controlled, balanced crossover design study will assess the effects of 75mg caffeine, 50mg l-theanine and a 75mg caffeine/50mg l-theanine combination in 24 young healthy adults (18-35). Cognitive and mood assessments will take place at baseline and at 30 minutes following treatment whilst cerebral haemodynamics are measured via the technique of NIRS.

Conditions

  • Cognitive Function
  • Mood

Interventions

DIETARY_SUPPLEMENT

Caffeine and L-theanine

Acute oral administration of 75mg of caffeine, 50mg l-theanine, 75mg caffeine and 50mg l-theanine in combination or placebo. One dosage administered on each of four separate study days.

Sponsors & Collaborators

  • Northumbria University

    lead OTHER

Principal Investigators

  • Crystal Haskell, PhD · Northumbria University

Study Design

Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Model
CROSSOVER

Eligibility

Min Age
18 Years
Max Age
35 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2009-08-31
Primary Completion
2010-02-28
Completion
2010-02-28

Countries

  • United Kingdom

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00981955 on ClinicalTrials.gov