Effects of l-theanine on attention and reaction time response

Higashiyama, Akiko; Htay, Hla; Ozeki, Makoto; Juneja, Lekh Raj; Kapoor, Mahendra P.

doi:10.1016/j.jff.2011.03.009

Cited by 42 publications

(38 citation statements)

References 34 publications

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“…This finding goes in line with the caffeine related improved performance in the Berg's Card Sorting Test (BCST) and simple reaction time tasks and supports previous findings that showed caffeine induced facilitation of attention [32,44] and level of alertness [13,45]. It is also consistent with other previous studies [2,16,19,38] that linked consumption of tea to robust increases in alertness and information processing capacity [4]. As cholinergic mechanisms have been shown to be a necessary condition for memory formation in rats [46], we hypothesize that BT might also be able to influence the level of cholinergic mechanisms in humans, thus improving memory formation [46].…”

Section: Discussionsupporting

confidence: 92%

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The effect of black tea on human cognitive performance in a cognitive test battery

et al. 2017

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Background: Black Tea is a widely consumed drink in the world. Evidence suggest Black Tea has stimulatory effect on humans. We investigated the effect of Black Tea on cognition using a cognitive test battery. Methods: Participants (n = 32) were fasted overnight for 10 h and restrained from caffeine and other stimulant drugs for 14 days prior to participation. We randomly assigned participants into either an experimental (n = 16) or a control (n = 16) group. Experimental group consumed 250 ml of Black Tea (BT) while control group was received equal volume of water (W). Participants were tested on the following cognitive tasks: executive function, sustained attention, memory (memory span, immediate, delayed, working memory) and arithmetic calculation task. Conclusions: BT consumption speeded the performance, improved memory, reduced number of errors in the various cognitive tasks. Our results further showed that even in small volume of BT consumption can speed up cognitive processing.

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Section: Discussionsupporting

confidence: 92%

“…Caffeine improves low alertness during long drive [14]. Besides caffeine, Theanine improves attentional performance at a dose of 200 mg/100 ml water [19]. Important to notice, effect of caffeine is shown to be related to the habitual intake levels.…”

Section: Introductionmentioning

confidence: 92%

The effect of black tea on human cognitive performance in a cognitive test battery

et al. 2017

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“…[3] and Higashiyama et al . [23]; and 250 mg in Gomez-Ramirez et al . [24]), the low dose of 52 mg in shaded white tea in this study might have been insufficient.…”

Section: Discussionmentioning

confidence: 99%

Intake of green tea inhibited increase of salivary chromogranin A after mental task stress loads

Yoto

Murao

Nakamura

et al. 2014

J Physiol Anthropol

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BackgroundGreen tea has become renowned for its health benefits. In this study, we investigated the anti-stress effect of two kinds of green tea against a mental stress task load.MethodsWarm water, ordinary green tea (Sagara), and shaded white tea, which contains more amino acid components than Sagara, were used as test samples in a randomized cross-over design study. Eighteen students (nine male and nine female) participated in three experimental trials on different days at intervals of seven days. Saliva was collected before beverage intake and after performing the mental stress load tasks. Concentration of chromogranin A (CgA) in the saliva was used as an index of autonomic nervous system activity.ResultsCgA level increased after the mental tasks, but intake of green tea inhibited this increase; the anti-stress effect was even greater after consumption of shaded white tea. Intake of shaded white tea also lowered Total Mood Disturbance (TMD) score on the Profile of Mood States (POMS); subjects in this condition tended to perform more calculations in the arithmetic task than those in the warm water treatment condition.ConclusionsSalivary CgA concentration levels increased after mental stress load tasks, but ingestion of green tea inhibited this increase. This anti-stress effect was larger after the consumption of shaded white tea than after Sagara. Shaded white tea intake also lowered TMD score (POMS) and tended to improve performance on an arithmetic task compared to warm water, suggesting that shaded white tea might also improve mood during and after mental stress load.

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“…Numerous studies have highlighted the effects of L-THE on learning ability and on a multitude of neuroprotective effects ( Table 2) [8]. One specific study, involving administration of L-THE (200 mg/100 mL water), reported profound effects on attention performance as well as on reaction time responses in normal healthy subjects prone to high anxiety [59]. There is also evidence to support its synergistic relationship with caffeine.…”

Section: Effect Of L-the On Cognition and Learning Abilitymentioning

confidence: 99%

l-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion

et al. 2016

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Tea has been consumed for thousands of years and is an integral part of people's daily routine, as an everyday drink and a therapeutic aid for health promotion. Consumption of tea has been linked to a sense of relaxation commonly associated with the content of the non-proteinogenic amino acid theanine, which is found within the tea leaves. The aim of this review article is to outline the current methods for synthesis, extraction and purification of theanine, as well as to examine its potential benefits related to human health. These include improvements in cognitive and immune function, cancer prevention, reduced cardiovascular risk and its potential usefulness as a functional food product.The relative concentration of L-THE in the Camellia sinensis plant varies between the plant's structures, over maturation and through the growth period. Recent studies have indicated that L-THE is distributed across the entirety of the plant with concentrations ranging between 1.2 and 6.2 mg/g fresh weight, with higher concentrations being expressed in the roots (6.2-13.7 mg/g). The biosynthesis of L-THE is proposed to occur in the roots of the plant and it is then transported towards the leaves [11]. The shading treatment and nitrogen fertilisation have been shown to influence the L-THE levels and the total free amino acid content in the Camellia sinensis plant [12]. Although most often related to GT, L-THE is present at similar levels in other types of teas made from the plant, including black, white and oolong teas [13]. Chemical, Physical and Flavour PropertiesL-THE is a water soluble non-proteinous amino acid [14] containing a glutamine backbone within the core of L-THE as well as existing as an ethylamide derivate of glutamate [15]. It is stable in acidic conditions but yields glutamic acid and ethylamine during base hydrolysis [8,16]. L-THE is insoluble in organic solvents such as chloroform and methanol, which facilitates the easy separation of L-THE from caffeine, catechins and other lipophilic tea constituents [8]. Aqueous L-THE solutions (1% (w/v)) stabilised at pH 5-6, were found to be stable (>1 year) under normal environmental conditions [8,16,17] and have a boiling point higher than that of water (range 214-216˝C) [8]. Furthermore, its systematic nomenclature is described as (2S)-2-amino-5-(ethylamino)-5-oxopentanoic acid (C 7 H 14 N 2 O 3 , M.W. = 174.2 g/mol) [18]. and L-glutamic acid-gamma-ethylamide have also been used to denote L-THE and it is also available under the proprietary name Suntheanine ® [5,19]. Similar to other amino acids in nature, theanine is a chiral species and occurs predominantly as the L-(S) enantiomer (Figure 1), whereas a synthetically derived theanine is typically a racemic mix of L-and D-enantiomers. As such, the use of synthetically derived theanine may not necessarily exhibit the same physiological effects as theanine found "naturally" occurring in foods [8].

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Effects of l-theanine on attention and reaction time response

Cited by 42 publications

References 34 publications

The effect of black tea on human cognitive performance in a cognitive test battery

The effect of black tea on human cognitive performance in a cognitive test battery

Intake of green tea inhibited increase of salivary chromogranin A after mental task stress loads

l-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion

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