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

NCT00981955 | Completed Phase 4

• 1 other identifier: 25AA1
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 1

Brief 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

Keywords

Caffeine; Ltheanine; Near Infrared Spectroscopy; Cerebral Blood Flow; Cognitive Function; Mood

Outcome Measures

Primary Outcomes (3)

• Cerebral blood flow

  0-80 minutes post dose

• Cognitive function

  0-70 minutes post-dose

• Mood

  85 minutes post dose

Study Arms (4)

75mg caffeine

ACTIVE COMPARATOR

Dietary Supplement: Caffeine and L-theanine

50mg l-theanine

ACTIVE COMPARATOR

Dietary Supplement: Caffeine and L-theanine

75mg caffeine and 50mg l-theanine

ACTIVE COMPARATOR

Dietary Supplement: Caffeine and L-theanine

0mg caffeine/l-theanine

PLACEBO COMPARATOR

Dietary Supplement: Caffeine and L-theanine

Interventions

Caffeine and L-theanine DIETARY_SUPPLEMENT

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.

Also known as: Sun-theanine (l-theanine)

0mg caffeine/l-theanine; 50mg l-theanine; 75mg caffeine; 75mg caffeine and 50mg l-theanine

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy
• Aged 18-35
• Either caffeine consumers (consume more than 150mg caffeine per day) or non-consumers (less than 44mg caffeine per day).

You may not qualify if:

• Smoke or consume any tobacco products
• Not proficient in English language
• Pregnant (or seeking to become pregnant)
• Taking recreational, over the counter/prescription medication (including the contraceptive pill), and/or dietary/herbal supplements
• Have food allergies or sensitivities
• Have history of/current head trauma, learning difficulties , ADHD, migraines or any gastric problems

Sponsors & Collaborators

• Northumbria University: lead

Study Sites (1)

Northumbria University

Newcastle upon Tyne, Tyne & Wear, Ne1 8ST, United Kingdom

Location

MeSH Terms

Interventions

Caffeine; theanine

Intervention Hierarchy (Ancestors)

Xanthines; Alkaloids; Heterocyclic Compounds; Purinones; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Study Officials

• Crystal Haskell, PhD

  Northumbria University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER

Study Record Dates

• First Submitted: September 21, 2009
• First Posted: September 22, 2009
• Study Start: August 1, 2009
• Primary Completion: February 1, 2010
• Study Completion: February 1, 2010
• Last Updated: July 23, 2010

Record last verified: 2010-07

Locations

GB (1)