Anti-Stress, Behavioural and Magnetoencephalography Effects of an l-Theanine-Based Nutrient Drink: A Randomised, Double-Blind, Placebo-Controlled, Crossover Trial
by
David J. White 1, Suzanne De Klerk 2, William Woods 3, Shakuntla Gondalia 1, Chris Noonan 4 and Andrew B. Scholey 1,*
David J. White 1, Suzanne De Klerk 2, William Woods 3, Shakuntla Gondalia 1, Chris Noonan 4 and Andrew B. Scholey 1,*
1
Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn VIC 3122, Australia
2
Division of Pharmacology, Utrecht University, 3508 TC Utrecht, The Netherlands
3
Brain and Psychological Sciences Research Centre, Swinburne University of Technology, Hawthorn VIC 3122, Australia
4
HealthGuidance, Inc., Santa Monica, CA 90403-5104, USA
*
Author to whom correspondence should be addressed.
Nutrients 2016, 8(1), 53; https://doi.org/10.3390/nu8010053
Received: 25 November 2015 / Revised: 14 December 2015 / Accepted: 11 January 2016 / Published: 19 January 2016
(This article belongs to the Special Issue Nutrition in Cognitive Function)
l-theanine (γ-glutamylethylamide) is an amino acid found primarily in the green tea plant. This study explored the effects of an l-theanine-based nutrient drink on mood responses to a cognitive stressor. Additional measures included an assessment of cognitive performance and resting state alpha oscillatory activity using magnetoencephalography (MEG). Thirty-four healthy adults aged 18–40 participated in this double-blind, placebo-controlled, balanced crossover study. The primary outcome measure, subjective stress response to a multitasking cognitive stressor, was significantly reduced one hour after administration of the l-theanine drink when compared to placebo. The salivary cortisol response to the stressor was reduced three hours post-dose following active treatment. No treatment-related cognitive performance changes were observed. Resting state alpha oscillatory activity was significantly greater in posterior MEG sensors after active treatment compared to placebo two hours post-dose; however, this effect was only apparent for those higher in trait anxiety. This change in resting state alpha oscillatory activity was not correlated with the change in subjective stress response or the cortisol response, suggesting further research is required to assess the functional relevance of these treatment-related changes in resting alpha activity. These findings further support the anti-stress effects of l-theanine.
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Keywords:
l-theanine; stress; mood; cognition; cortisol; alpha activity
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MDPI and ACS Style
White, D.J.; De Klerk, S.; Woods, W.; Gondalia, S.; Noonan, C.; Scholey, A.B. Anti-Stress, Behavioural and Magnetoencephalography Effects of an l-Theanine-Based Nutrient Drink: A Randomised, Double-Blind, Placebo-Controlled, Crossover Trial. Nutrients 2016, 8, 53.
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