Acute effects of theanine, caffeine and theanine-caffeine combination on attention
Kahathuduwa CN, Dassanayake TL, Amarakoon AMT, Weerasinghe VS
Nutritional neuroscience · 41 citations
How it was studied
- Design
- Randomized controlled trial (indexed by PubMed)
- Studied in
- People
- Main outcome
- Health markers and function
Who paid for it
- Funding
- Independent funding
- Government
- National Research Council Grant, Sri Lanka
Based on 1 listed funder(s).
Publication
- Published
- 2016-02-12 · Nutr Neurosci · vol. 20 · issue 6 · pp. 369–377
- Publisher
- Taylor & Francis
- Cited
- 71 citations · more than 92% of similar papers · 3.5× the field average
- Impact
- Top 10% most cited in its field
- References
- 41 works
- Access
- Paywalled
- Research areas
- Tea Polyphenols and Effects · Coffee research and impacts · Sirtuins and Resveratrol in Medicine
- Keywords
- Caffeine, Theanine, Placebo, Crossover study, Neurophysiology, Evoked potential, Cognition, Anesthesia, Pharmacology, Psychology, Audiology, Medicine, Internal medicine, Chemistry, Neuroscience, Food science, Green tea
- MeSH
- humans, caffeine, glutamates, nootropic agents, cross-over studies, motor activity, cognition, pattern recognition, visual, attention, reaction time, evoked potentials, motor, evoked potentials, visual, students, universities, coffee, tea, dietary supplements, adult, sri lanka, male, young adult, performance-enhancing substances
4 authors
From LK, US
- Chanaka Nadeeshan KahathuduwaUniversity of Peradeniya; Texas Tech University
- Tharaka L. Dassanayake · correspondingUniversity of Peradeniya
- A. M. T. AmarakoonUniversity of Kelaniya
- Vajira Senaka WeerasingheUniversity of Peradeniya
Abstract
Objective
l-theanine is a constituent of tea which is claimed to enhance cognitive functions. We aimed to determine whether theanine and theanine-caffeine combination have acute positive effects on cognitive and neurophysiological measures of attention, compared to caffeine (a positive control) and a placebo in healthy individuals.
Design
In a placebo-controlled, five-way crossover trial in 20 healthy male volunteers, we compared the effects of l-theanine (200 mg), caffeine (160 mg), their combination, black tea (one cup) and a placebo (distilled water) on cognitive (simple [SVRT] and recognition visual reaction time [RVRT]) and neurophysiological (event-related potentials [ERPs]) measures of attention. We also recorded visual (VEPs) and motor evoked potentials (MEPs) to examine any effects of treatments on peripheral visual and motor conduction, respectively.
Results
Mean RVRT was significantly improved by theanine (P = 0.019), caffeine (P = 0.043), and theanine-caffeine combination (P = 0.001), but not by tea (P = 0.429) or placebo (P = 0.822). VEP or MEP latencies or SVRT did not show significant inter-treatment differences. Theanine (P = 0.001) and caffeine (P = 0.001) elicited significantly larger mean peak-to-peak N2-P300 ERP amplitudes than the placebo, whereas theanine-caffeine combination elicited a significantly larger mean N2-P300 amplitude than placebo (P < 0.001), theanine (P = 0.029) or caffeine (P = 0.005). No significant theanine × caffeine interaction was observed for RVRT or N2-P300 amplitude.
Discussion
A dose of theanine equivalent of eight cups of back tea improves cognitive and neurophysiological measures of selective attention, to a degree that is comparable with that of caffeine. Theanine and caffeine seem to have additive effects on attention in high doses.
Abstract via Europe PMC. Copyright remains with the authors or publisher.
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