@article{ref1,
title="Acute effects of theanine, caffeine and theanine-caffeine combination on attention",
journal="Nutritional neuroscience",
year="2016",
author="Kahathuduwa, Chanaka N. and Dassanayake, Tharaka Lagath and Amarakoon, A. M. Tissa and Weerasinghe, Vajira S.",
volume="20",
number="6",
pages="369-377",
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. <br><br>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. <br><br>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.<p /> <p>Language: en</p>",
language="en",
issn="1028-415X",
doi="10.1080/1028415X.2016.1144845",
url="http://dx.doi.org/10.1080/1028415X.2016.1144845"
}