l-Theanine reduces psychological and physiological stress responses

Kimura, Kenta; Ozeki, Makoto; Juneja, Lekh Raj; Ohira, Hideki

doi:10.1016/j.biopsycho.2006.06.006

Cited by 292 publications

(207 citation statements)

References 26 publications

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“…As an amino acid in green tea with positive psychological effects (Nobre et al, 2008;Gomez-Ramirez et al, 2007;Lu et al, 2004;Kimura et al, 2007;Yokogoshi and Terashima, 2000) theanine has been found to have a preferred taste at concentrations of 100 mM or less (Morita et al, 2006;Narukawa et al, 2008). We thus investigated whether aversive tastes such as sourness could be improved by the addition of theanine, due to its unique characteristics.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, the psychological effects of theanine have been investigated. Theanine has been found to have an impact on brain activity (Nobre et al, 2008;GomezRamirez et al, 2007), with positive effects on psychological outcomes, such as enhanced cognitive performance (Lu et al, 2004;Kimura et al, 2007) and psychological well-being (Juneja et al, 1999;Yokogoshi and Terashima, 2000). However, little is known about the sensory characteristics of this amino acid.…”

Section: Introductionmentioning

confidence: 99%

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Suppression of Sourness by Theanine

Narukawa

Sasaki

Kimata

et al. 2010

FSTR

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Theanine is a unique amino acid present in green tea. It is partly responsible for the taste of green tea and possesses various psychological effects. Theanine has a preferred taste, like umami and sweetness. Therefore, theanine may improve unpleasant tastes such as bitterness and sourness of foods. To investigate new uses of theanine, we investigated its taste-modifying effect by human sensory evaluation. A reduction in sourness was observed with theanine addition. Investigation of the mechanism of taste improvement found that sourness is relatively improved by theanine addition due to the increase in pH and the addition of the umami taste.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Suppression of Sourness by Theanine

Narukawa

Sasaki

Kimata

et al. 2010

FSTR

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“…Another randomised, double-blind, placebo-controlled, cross-over (Latin square design) study examined psychological and physiological responses to stress in 12 healthy male volunteers (age range: 20-25 years) after consumption of L-theanine (200 mg dissolved in 100 mL of water), placebo (water alone), or when receiving no treatment in four test sessions (Kimura et al, 2007). Each experimental session began with a 20 min rest period, followed by a mental arithmetic task for 20 min to induce stress, and then by two rest periods of 10 min.…”

Section: Alleviation Of Psychological Stress (Id 1598 1601)mentioning

confidence: 99%

Scientific Opinion on the substantiation of health claims related to L-theanine from Camellia sinensis (L.) Kuntze (tea) and improvement of cognitive function (ID 1104, 1222, 1600, 1601, 1707, 1935, 2004, 2005), alleviation of psychological stress (ID 159

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2011

EFSA Journal

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SUMMARYFollowing a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to provide a scientific opinion on a list of health claims pursuant to Article 13 of Regulation (EC) No 1924No /2006. This opinion addresses the scientific substantiation of health claims in relation to L-theanine from Camellia sinensis (L.) Kuntze (tea) and improvement of cognitive function, alleviation of psychological stress, maintenance of normal sleep and reduction of menstrual discomfort. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly from stakeholders.The food/constituents that are the subject of the health claims are Camellia sinensis (L.) Kuntze (tea) and L-theanine. The Panel considers that while Camellia sinensis (L.) Kuntze (tea) is not sufficiently characterised in relation to the claimed effects, L-theanine from Camellia sinensis (L.) Kuntze (tea) is sufficiently characterised. Improvement of cognitive functionThe claimed effects are "physical and mental stimulation (hydration and caffeine)", "mental and cognitive health", "cognitive function", "neurological functions", "physiological antagonistic against caffeine", and "cognitive performance: focussed attention". The target population is assumed to be the general population. In the context of the proposed wordings and clarifications from Member States, the Panel assumes that the claimed effects refer to improvement of cognitive function. The Panel considers that improvement of cognitive function is a beneficial physiological effect.In weighing the evidence, the Panel took into account that the three human studies from which conclusions could be drawn for the scientific substantiation of the claim did not show an effect of L-theanine on improvement of cognitive function.On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of L-theanine from Camellia Sinensis (L.) Kuntze (tea) and improvement of cognitive function. Alleviation of psychological stressThe claimed effects are "relaxation" and "neurological functions". The target population is assumed to be the general population. In the context of the proposed wordings, clarifications from Member States and references provided, the Panel assumes that the claimed effects refer to alleviation of psychological stress. The Panel considers that alleviation of psychological stress might be a beneficial physiological effect.No references were provided from which conclusions could be drawn for the scientific substantiation of the claim.On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of L-theanine from Camellia Sinensis (L.) Kuntze (tea) and alleviation of psychological stress. Maintenance of normal sleepThe claimed effects are "mental and cognitive ...

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“…Recent evidence showed that nutritional interventions exert a beneficial effect on many of the biological risk factors produced by stress, (17) cocoa products being one of them. Chocolate has been shown to reduce stress in highly stressed, (18) as well as normal healthy individuals (19) in two randomized controlled studies.…”

Section: Introductionmentioning

confidence: 99%