The Effects of Caffeine and L-theanine Both Alone and in Combination on Cerebral Blood Flow, Cognition and Mood
- Full Text View
- Tabular View
- No Study Results Posted
- Disclaimer
- How to Read a Study Record
Purpose
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.
| Condition | Intervention | Phase |
|---|---|---|
|
Cognitive Function Mood |
Dietary Supplement: Caffeine and L-theanine |
Phase 4 |
| Study Type: | Interventional |
| Study Design: | Allocation: Randomized Endpoint Classification: Efficacy Study Intervention Model: Crossover Assignment Masking: Double Blind (Subject, Investigator, Outcomes Assessor) Primary Purpose: Basic Science |
| Official Title: | A Randomised, Double Blind, Placebo-controlled Study to Evaluate the Effects of Caffeine and L-theanine Both Alone and in Combination on Cerebral Blood Flow, Cognition and Mood. |
- Cerebral blood flow [ Time Frame: 0-80 minutes post dose ] [ Designated as safety issue: No ]
- Cognitive function [ Time Frame: 0-70 minutes post-dose ] [ Designated as safety issue: No ]
- Mood [ Time Frame: 85 minutes post dose ] [ Designated as safety issue: No ]
| Enrollment: | 24 |
| Study Start Date: | August 2009 |
| Study Completion Date: | February 2010 |
| Primary Completion Date: | February 2010 (Final data collection date for primary outcome measure) |
| Arms | Assigned Interventions |
|---|---|
| Active Comparator: 75mg caffeine |
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.
Other Name: Sun-theanine (l-theanine)
|
| Active Comparator: 50mg l-theanine |
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.
Other Name: Sun-theanine (l-theanine)
|
| Active Comparator: 75mg caffeine and 50mg l-theanine |
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.
Other Name: Sun-theanine (l-theanine)
|
| Placebo Comparator: 0mg caffeine/l-theanine |
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.
Other Name: Sun-theanine (l-theanine)
|
Eligibility| Ages Eligible for Study: | 18 Years to 35 Years |
| Genders Eligible for Study: | Both |
| Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Healthy
- Aged 18-35
- Either caffeine consumers (consume more than 150mg caffeine per day) or non-consumers (less than 44mg caffeine per day).
Exclusion Criteria:
- 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
Contacts and Locations| United Kingdom | |
| Northumbria University | |
| Newcastle upon Tyne, Tyne & Wear, United Kingdom, Ne1 8ST | |
| Principal Investigator: | Crystal Haskell, PhD | Northumbria University |
More Information
No publications provided
| Responsible Party: | Dr Crystal Haskell, Northumbria University |
| ClinicalTrials.gov Identifier: | NCT00981955 History of Changes |
| Other Study ID Numbers: | 25AA1 |
| Study First Received: | September 21, 2009 |
| Last Updated: | July 22, 2010 |
| Health Authority: | United Kingdom: Research Ethics Committee |
Keywords provided by Northumbria University:
|
Caffeine Ltheanine Near Infrared Spectroscopy |
Cerebral Blood Flow Cognitive Function Mood |
Additional relevant MeSH terms:
|
Caffeine Central Nervous System Stimulants Physiological Effects of Drugs Pharmacologic Actions Central Nervous System Agents Therapeutic Uses Phosphodiesterase Inhibitors |
Enzyme Inhibitors Molecular Mechanisms of Pharmacological Action Purinergic P1 Receptor Antagonists Purinergic Antagonists Purinergic Agents Neurotransmitter Agents |
ClinicalTrials.gov processed this record on May 21, 2013