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Wikipedia

Theanine

January 08, 2023

Not to be confused with threonine, a distinct amino acid, or theine, an archaic synonym of caffeine.

Theanine /ˈθiːəniːn/, also known as L-γ-glutamylethylamide and N5-ethyl-L-glutamine, is an amino acid analogue of the proteinogenic amino acids L-glutamate and L-glutamine and is found primarily in particular plant and fungal species. It was discovered as a constituent of green tea in 1949; in 1950, it was isolated from gyokuro leaves.[4] Theanine provides a unique brothy or savory (umami) flavor to green tea infusions.

Theanine
L-Theanine
Clinical data
Other namesγ-L-Glutamylethylamide
Dependence
liability		None
Routes of
administration		Oral
ATC code
  • none
Legal status
Legal status
  • US: OTC
  • UN: Unscheduled
Pharmacokinetic data
Onset of actionabout 1 hour[1]
Elimination half-lifeCapsule ~1.2 hours
Green Tea ~0.8 hours[1]
Identifiers
  • (2S)-2-Ammonio-5-(ethylamino)-5-oxopentanoate[2] or N-Ethyl-L-glutamine
CAS Number
  • 3081-61-6 Y
PubChem CID
  • 439378
DrugBank
  • DB12444
ChemSpider
  • 388498 Y
UNII
  • 8021PR16QO
KEGG
  • C01047
ChEBI
  • CHEBI:17394 Y
ChEMBL
  • ChEMBL3039113
CompTox Dashboard (EPA)
  • DTXSID80184817
ECHA InfoCard100.019.436
Chemical and physical data
FormulaC7H14N2O3
Molar mass174.200 g·mol−1
3D model (JSmol)
  • Interactive image
  • Interactive image
Melting point174.20 °C (345.56 °F) [3]
Boiling point215 °C (419 °F) [3]
  • CCNC(=O)CC[C@H](N)C(=O)O

  • CCNC(=O)CCC(N)C(O)=O
  • InChI=1S/C7H14N2O3/c1-2-9-6(10)4-3-5(8)7(11)12/h5H,2-4,8H2,1H3,(H,9,10)(H,11,12) Y
  • Key:DATAGRPVKZEWHA-UHFFFAOYSA-N Y

The name "theanine" without a prefix generally implies the enantiomer L-theanine, which is the form found in tea leaves and as a dietary supplement ingredient. Most studies have used L-theanine. The opposite enantiomer, D-theanine, has been studied less.

The regulatory status of theanine varies by country. In Japan, L-theanine has been approved for use in all foods, with some restrictions in the case of infant foods.[5][6] In the United States, the Food and Drug Administration (FDA) considers it to be generally recognized as safe (GRAS) and allows its sale as a dietary supplement. The German Federal Institute for Risk Assessment, an agency of their Federal Ministry of Food and Agriculture, objects to the addition of L-theanine to beverages. In 2011 the European Food Safety Authority, when asked to provide a scientific opinion, concluded that a cause and effect relationship had not been established between consumption of L-theanine and improved cognitive function, alleviation of psychological stress, maintenance of normal sleep, or reduction of menstrual discomfort.[7] Therefore, health claims for L-theanine are not recognized in the European Union.[8]

Structure and properties

The chemical name N5-ethyl-L-glutamine[2] and other synonyms (see box) for theanine reflect its chemical structure. The name theanine, without prefix, is generally understood to imply the L- (S-) enantiomer, derived from the related proteinogenic L-amino acid glutamic acid. Theanine is an analog of this amino acid, and its primary amide, L-glutamine (also a proteinogenic amino acid). Theanine is a derivative of glutamine that is ethylated on the amide nitrogen (as the name N5-ethyl-L-glutamine describes), or alternatively, to the amide formed from ethylamine and L-glutamic acid at its γ- (5-) side chain carboxylic acid group (as the name γ-L-glutamylethylamide describes).

Relative to theanine, the opposite (D-, R-) enantiomer is largely absent from the literature,[2] except implicitly. While natural extracts that are not harshly treated are presumed to contain only the biosynthetic L- enantiomeric form, mishandled isolates and racemic chemical preparations of theanines necessarily contain both theanine and its D-enantiomer (and from racemic syntheses, in equal proportion), and studies have suggested that the D-isomer may actually predominate in some commercial supplement preparations.[9][10] Amino acid racemization in aqueous media is a well-established chemical process promoted by elevated temperature and non-neutral pH values; prolonged heating of Camellia extracts—possible for oversteeped teas and in undisclosed commercial preparative processes—has been reported to result in increasing racemization of theanine to give increasing proportions of the nonnatural D-theanine, up to equal proportions of each enantiomer.[10]

Discovery and distribution

Theanine is found primarily in plant and fungal species. It was discovered as a constituent of tea (Camellia sinensis) in 1949, and in 1950 a laboratory in Kyoto[5] successfully isolated it from gyokuro leaf, which has high theanine content.[11] Theanine is substantially present in black, green, and white teas from Camellia sinensis in quantities of about 1% of the dry weight.[12][13] Deliberately shading tea plants from direct sunlight, as is done for matcha and gyokuro green tea, increases L-theanine content.[citation needed] The L-enantiomer[2] is the form found in freshly prepared teas and some human dietary supplements.[10]

Digestion and metabolism

As a structural analog of glutamate and glutamine, the theanine in preparations (teas, pure supplements, etc.) is absorbed in the small intestine after oral ingestion; its hydrolysis to L-glutamate and ethylamine occur both in the intestine and liver, so theanine can be considered to function as a donor that supplies glutamate to the body.[14] Glutamate can be metabolized to glutamine in astrocytes, a process catalysed by Glutamine synthetase and can also be decarboxylated to GABA by Glutamate decarboxylase, thus theanine can supply the neurotransmitter pools of amino acids.[15] It can also cross the blood–brain barrier intact, and register pharmacological effects directly.[16]

Pharmacology

Pharmacodynamics

Theanine is structurally similar to the excitatory neurotransmitter glutamate, and in accordance, binds to glutamate receptors, though with much lower affinity in comparison. Specifically, it binds to ionotropic glutamate receptors in the micromolar range, including the AMPA and kainate receptors and, to a lesser extent, the NMDA receptor.[17][18][19][20] It acts as an antagonist of the former two sites, and a partial co-agonist of the NMDA receptors.[20][21] Theanine also binds to group I mGluRs.[17][22] In addition, it inhibits glutamine transporters and glutamate transporters, and thus blocks the reuptake of glutamine and glutamate.[19][23][24] Lastly, theanine elicits umami taste, and this effect has been found to be a consequence of the fact that it directly binds to and activates the T1R1 + T1R3 heterodimer or umami (savory) taste receptor.[25]

Theanine increases serotonin, dopamine and glycine levels in various areas of the brain, as well as BDNF and NGF levels in certain brain areas.[17][26][27][28] However, its effect on serotonin is still a matter of debate in the scientific community, with studies showing increases and decreases in brain serotonin levels using similar experimental protocols.[16][29] It has also been found that injecting spontaneously hypertensive mice with theanine significantly lowered levels of 5-hydroxyindoles in the brain.[30] Researchers also speculate that it may inhibit glutamate excitotoxicity.[17]

Effects

A 2014 Natural Standard monograph that reviewed research on theanine reports that it is likely safe in doses of 200–250 mg up to a maximum daily dose of 1,200 mg. Natural Standard rates the evidence to support the usage of theanine for anxiety reduction, blood pressure control, and mood improvement as "unclear or conflicting scientific evidence" and the evidence for improved cognition as "fair negative scientific evidence". Many of the studies of theanine were done in combination with caffeine as found in tea. While the studies found that the combination had some effect on mood, the studies found that theanine alone had little effect.[31]

However a review by other researchers of a small set of trials concluded that there are benefits of L-theanine in reducing acute stress and anxiety in people with stressful conditions.[32] and other subsequent studies have also concluded that it has an effect on reducing anxiety.[33][34]

In 2011, the EFSA (European Food Safety Authority) intervened with a scientific opinion on the alleged properties of L-theanine (improvement of cognitive functions, alleviation of psychological stress, maintenance of normal sleep conditions, reduction of menstrual pain) and concluded that at present there is no scientific evidence of a cause-and-effect relationship between the intake of L-theanine and the indicated benefits.[35]

Supplement use

 
Tub of theanine capsules

A 2020 systematic review concluded that L-theanine supplementation between 200 and 400 mg per day may help reduce stress and anxiety acutely in people with acute stress, but there is insufficient evidence for treatment of chronic stress. It further concluded that longer term and larger clinical study is needed to clinically justify its use therapeutically.[36]

In 2003, the German Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung, BfR) objected to the addition of isolated theanine to beverages.[37][38] The institute stated the amount of theanine consumed by regular drinkers of tea or coffee is virtually impossible to determine. While it was estimated the quantity of green tea consumed by the average Japanese tea drinker per day contains about 20 mg of the substance, there are no studies measuring the amount of theanine being extracted by typical preparation methods, or the percentage lost by discarding the first infusion. Therefore, with the Japanese being exposed to possibly much less than 20 mg per day, and Europeans presumably even less, it was the opinion of the BfR that pharmacological reactions to drinks typically containing 50 mg of theanine per 500 milliliters could not be excluded—reactions such as impairment of psychomotor skills and amplification of the sedating effects of alcohol and hypnotics.[39]

The combination of theanine and caffeine has been shown to promote faster simple reaction time, faster numeric working memory reaction time and improved sentence verification accuracy.[40][41][42][43] Studies have also concluded that an L-theanine and caffeine combination have improved sustained attention, impulsivity and cognition in children diagnosed with ADHD.[44][45][46]

Theanine has been reported to raise levels of brain serotonin and dopamine, with possible improvement in specific memory and learning tasks.[47][48][49]

In brewed teabags

A study of teabags sold in British supermarkets in 2011 found that the teabags containing the most L-theanine per cup (24 mg versus 8 mg per cup) were the lower-quality brands containing black tea, with a supermarket brand of black tea having the highest theanine content. The study demonstrates that brewing time is a major determinant of the amount of l-theanine extracted. Addition of sugar and small quantities of milk make no significant difference, while larger quantities of milk reduced the measured theanine content.[50]

See also

References

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  2. ^ a b c d "D-theanine | C7H14N2O3". ChemSpider.com. Retrieved 2015-05-21.
  3. ^ a b "Theanine". Pubchem Compound. NCBI. Retrieved 21 February 2015.
  4. ^ "Components of Gyokuro｜ IPPODO". Ippodo-tea.co.jp. Retrieved 2015-05-07.
  5. ^ a b Sakato,Y. J. Agri. Chem. Soc. 1949, 23, 262–267
  6. ^ Mason R. Altern. & Complementary Ther. 2001, 7, 91–95
  7. ^ "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 1598, 1601), maintenance of normal sleep (ID 1222, 1737, 2004) and reduction of menstrual discomfort (ID 1599) pursuant to Article 13(1) of Regulation (EC) No 1924/2006 | European Food Safety Authority".
  8. ^ "EU Register on nutrition and health claims". European Commission. p. 153. Retrieved 2021-08-10.
  9. ^ Vuong, Quan V; Bowyer, Michael C; Roach, Paul D (2011). "L-Theanine: Properties, synthesis and isolation from tea". Journal of the Science of Food and Agriculture. 91 (11): 1931–1939. doi:10.1002/jsfa.4373. PMID 21735448.
  10. ^ a b c Desai, M. J.; Armstrong, D. W. (2004). "Analysis of derivatized and underivatized theanine enantiomers by high-performance liquid chromatography/atmospheric pressure ionization-mass spectrometry". Rapid Communications in Mass Spectrometry. 18 (3): 251–256. Bibcode:2004RCMS...18..251D. doi:10.1002/rcm.1319. PMID 14755608.
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  28. ^ Yokogoshi H, Kobayashi M, Mochizuki M, Terashima T (1998). "Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats". Neurochem. Res. 23 (5): 667–673. doi:10.1023/A:1022490806093. PMID 9566605. S2CID 24749717.
  29. ^ Yokogoshi, Hidehiko; Mochizuki, Mikiko; Saitoh, Kotomi (1998). "Theanine-induced Reduction of Brain Serotonin Concentration in Rats". Bioscience, Biotechnology, and Biochemistry. 62 (4): 816–817. doi:10.1271/bbb.62.816. PMID 9614715.
  30. ^ Yokogoshi, Hidehiko; Kato, Yukiko; Sagesaka, Yuko M.; Takihara-Matsuura, Takanobu; Kakuda, Takami; Takeuchi, Naokazu (1995). "Reduction Effect of Theanine on Blood Pressure and Brain 5-Hydroxyindoles in Spontaneously Hypertensive Rats". Bioscience, Biotechnology, and Biochemistry. 59 (4): 615–618. doi:10.1271/bbb.59.615. PMID 7539642.
  31. ^ . Natural Standard. Archived from the original on December 24, 2014. Retrieved 30 October 2014.
  32. ^ Everett, J.M.; Gunathilake, D.; Dufficy, L.; Roach, P.; Thomas, J.; Upton, D.; Naumovski, N. (2016). "Theanine consumption, stress and anxiety in human clinical trials: A systematic review". Journal of Nutrition & Intermediary Metabolism. 4: 41–42. doi:10.1016/j.jnim.2015.12.308.
  33. ^ Hidese, S.; Ogawa, S.; Ota, M.; Ishida, I.; Yasukawa, Z.; Ozeki, M.; Kunugi, H. (2019). "Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial". Nutrients. 11 (10): 2362. doi:10.3390/nu11102362. PMC 6836118. PMID 31623400.
  34. ^ Evans, Malkanthi; McDonald, Alison C.; Xiong, Lora; Crowley, David C.; Guthrie, Najla (2021). "A Randomized, Triple-Blind, Placebo-Controlled, Crossover Study to Investigate the Efficacy of a Single Dose of AlphaWave® L-Theanine on Stress in a Healthy Adult Population". Neurology and Therapy. 10 (2): 1061–1078. doi:10.1007/s40120-021-00284-x. PMC 8475422. PMID 34562208.
  35. ^ Type: Opinion of the Scientific Committee/Scientific Panel On request from: European Commission Question number: EFSA-Q-2008-1843 , EFSA-Q-2008-1960 , EFSA-Q-2008-2334 , EFSA-Q-2008-2335 , EFSA-Q-2008-2336 , EFSA-Q-2008-2337 , EFSA-Q-2008-2443 , EFSA-Q-2008-2473 , EFSA-Q-2008-2668 , EFSA-Q-2008-2737 , EFSA-Q-2008-2738 Adopted: 08 April 2011 Published: 30 June 2011 Affiliation: European Food Safety Authority (EFSA), Parma, Italy
  36. ^ Williams JL, Everett JM, D'Cunha NM, Sergi D, Georgousopoulou EN, Keegan RJ; et al. (2020). "The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review". Plant Foods Hum Nutr. 75 (1): 12–23. doi:10.1007/s11130-019-00771-5. PMID 31758301. S2CID 208213702. The supplementation of L-THE in its pure form at dosages between 200 and 400 mg/day may help reduce stress and anxiety acutely in people undergoing acute stressful situations, but there is insufficient evidence to suggest it assists in the reduction of stress levels in people with chronic conditions. However, the results of this study suggest that L-THE taken during times of heightened acute stress or by individuals with a high propensity for anxiety and stress may exhibit beneficial properties via the increased production of alpha waves and decrease of glutamate in the brain.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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Further reading

  • E.K. Keenan; M.D.A. Finnie; P.S. Jones; P.J. Rogers; C.M. Priestley (2011). "How much theanine in a cup of tea? Effects of tea type and method of preparation". Food Chemistry. 125 (2): 588–594. doi:10.1016/j.foodchem.2010.08.071.
  • Y. Orihara; T. Furuya (1990). "Production of theanine and other γ-glutamyl derivatives by Camellia sinensis cultured cells". Plant Cell Reports. 9 (2): 65–68. doi:10.1007/BF00231550. PMID 24226431. S2CID 23515765.

January 08, 2023
theanine, confused, with, threonine, distinct, amino, acid, theine, archaic, synonym, caffeine, also, known, glutamylethylamide, ethyl, glutamine, amino, acid, analogue, proteinogenic, amino, acids, glutamate, glutamine, found, primarily, particular, plant, fu. Not to be confused with threonine a distinct amino acid or theine an archaic synonym of caffeine Theanine ˈ 8 iː en iː n also known as L g glutamylethylamide and N5 ethyl L glutamine is an amino acid analogue of the proteinogenic amino acids L glutamate and L glutamine and is found primarily in particular plant and fungal species It was discovered as a constituent of green tea in 1949 in 1950 it was isolated from gyokuro leaves 4 Theanine provides a unique brothy or savory umami flavor to green tea infusions TheanineL TheanineClinical dataOther namesg L GlutamylethylamideDependenceliabilityNoneRoutes ofadministrationOralATC codenoneLegal statusLegal statusUS OTC UN UnscheduledPharmacokinetic dataOnset of actionabout 1 hour 1 Elimination half lifeCapsule 1 2 hours Green Tea 0 8 hours 1 IdentifiersIUPAC name 2S 2 Ammonio 5 ethylamino 5 oxopentanoate 2 or N Ethyl L glutamineCAS Number3081 61 6 YPubChem CID439378DrugBankDB12444ChemSpider388498 YUNII8021PR16QOKEGGC01047ChEBICHEBI 17394 YChEMBLChEMBL3039113CompTox Dashboard EPA DTXSID80184817ECHA InfoCard100 019 436Chemical and physical dataFormulaC 7H 14N 2O 3Molar mass174 200 g mol 13D model JSmol Interactive imageInteractive imageMelting point174 20 C 345 56 F 3 Boiling point215 C 419 F 3 SMILES CCNC O CC C H N C O OCCNC O CCC N C O OInChI InChI 1S C7H14N2O3 c1 2 9 6 10 4 3 5 8 7 11 12 h5H 2 4 8H2 1H3 H 9 10 H 11 12 YKey DATAGRPVKZEWHA UHFFFAOYSA N YThe name theanine without a prefix generally implies the enantiomer L theanine which is the form found in tea leaves and as a dietary supplement ingredient Most studies have used L theanine The opposite enantiomer D theanine has been studied less The regulatory status of theanine varies by country In Japan L theanine has been approved for use in all foods with some restrictions in the case of infant foods 5 6 In the United States the Food and Drug Administration FDA considers it to be generally recognized as safe GRAS and allows its sale as a dietary supplement The German Federal Institute for Risk Assessment an agency of their Federal Ministry of Food and Agriculture objects to the addition of L theanine to beverages In 2011 the European Food Safety Authority when asked to provide a scientific opinion concluded that a cause and effect relationship had not been established between consumption of L theanine and improved cognitive function alleviation of psychological stress maintenance of normal sleep or reduction of menstrual discomfort 7 Therefore health claims for L theanine are not recognized in the European Union 8 Contents 1 Structure and properties 2 Discovery and distribution 3 Digestion and metabolism 4 Pharmacology 4 1 Pharmacodynamics 4 2 Effects 5 Supplement use 6 In brewed teabags 7 See also 8 References 9 Further readingStructure and properties EditThe chemical name N5 ethyl L glutamine 2 and other synonyms see box for theanine reflect its chemical structure The name theanine without prefix is generally understood to imply the L S enantiomer derived from the related proteinogenic L amino acid glutamic acid Theanine is an analog of this amino acid and its primary amide L glutamine also a proteinogenic amino acid Theanine is a derivative of glutamine that is ethylated on the amide nitrogen as the name N5 ethyl L glutamine describes or alternatively to the amide formed from ethylamine and L glutamic acid at its g 5 side chain carboxylic acid group as the name g L glutamylethylamide describes Relative to theanine the opposite D R enantiomer is largely absent from the literature 2 except implicitly While natural extracts that are not harshly treated are presumed to contain only the biosynthetic L enantiomeric form mishandled isolates and racemic chemical preparations of theanines necessarily contain both theanine and its D enantiomer and from racemic syntheses in equal proportion and studies have suggested that the D isomer may actually predominate in some commercial supplement preparations 9 10 Amino acid racemization in aqueous media is a well established chemical process promoted by elevated temperature and non neutral pH values prolonged heating of Camellia extracts possible for oversteeped teas and in undisclosed commercial preparative processes has been reported to result in increasing racemization of theanine to give increasing proportions of the nonnatural D theanine up to equal proportions of each enantiomer 10 Discovery and distribution EditTheanine is found primarily in plant and fungal species It was discovered as a constituent of tea Camellia sinensis in 1949 and in 1950 a laboratory in Kyoto 5 successfully isolated it from gyokuro leaf which has high theanine content 11 Theanine is substantially present in black green and white teas from Camellia sinensis in quantities of about 1 of the dry weight 12 13 Deliberately shading tea plants from direct sunlight as is done for matcha and gyokuro green tea increases L theanine content citation needed The L enantiomer 2 is the form found in freshly prepared teas and some human dietary supplements 10 Digestion and metabolism EditAs a structural analog of glutamate and glutamine the theanine in preparations teas pure supplements etc is absorbed in the small intestine after oral ingestion its hydrolysis to L glutamate and ethylamine occur both in the intestine and liver so theanine can be considered to function as a donor that supplies glutamate to the body 14 Glutamate can be metabolized to glutamine in astrocytes a process catalysed by Glutamine synthetase and can also be decarboxylated to GABA by Glutamate decarboxylase thus theanine can supply the neurotransmitter pools of amino acids 15 It can also cross the blood brain barrier intact and register pharmacological effects directly 16 Pharmacology EditPharmacodynamics Edit Theanine is structurally similar to the excitatory neurotransmitter glutamate and in accordance binds to glutamate receptors though with much lower affinity in comparison Specifically it binds to ionotropic glutamate receptors in the micromolar range including the AMPA and kainate receptors and to a lesser extent the NMDA receptor 17 18 19 20 It acts as an antagonist of the former two sites and a partial co agonist of the NMDA receptors 20 21 Theanine also binds to group I mGluRs 17 22 In addition it inhibits glutamine transporters and glutamate transporters and thus blocks the reuptake of glutamine and glutamate 19 23 24 Lastly theanine elicits umami taste and this effect has been found to be a consequence of the fact that it directly binds to and activates the T1R1 T1R3 heterodimer or umami savory taste receptor 25 Theanine increases serotonin dopamine and glycine levels in various areas of the brain as well as BDNF and NGF levels in certain brain areas 17 26 27 28 However its effect on serotonin is still a matter of debate in the scientific community with studies showing increases and decreases in brain serotonin levels using similar experimental protocols 16 29 It has also been found that injecting spontaneously hypertensive mice with theanine significantly lowered levels of 5 hydroxyindoles in the brain 30 Researchers also speculate that it may inhibit glutamate excitotoxicity 17 Effects Edit A 2014 Natural Standard monograph that reviewed research on theanine reports that it is likely safe in doses of 200 250 mg up to a maximum daily dose of 1 200 mg Natural Standard rates the evidence to support the usage of theanine for anxiety reduction blood pressure control and mood improvement as unclear or conflicting scientific evidence and the evidence for improved cognition as fair negative scientific evidence Many of the studies of theanine were done in combination with caffeine as found in tea While the studies found that the combination had some effect on mood the studies found that theanine alone had little effect 31 However a review by other researchers of a small set of trials concluded that there are benefits of L theanine in reducing acute stress and anxiety in people with stressful conditions 32 and other subsequent studies have also concluded that it has an effect on reducing anxiety 33 34 In 2011 the EFSA European Food Safety Authority intervened with a scientific opinion on the alleged properties of L theanine improvement of cognitive functions alleviation of psychological stress maintenance of normal sleep conditions reduction of menstrual pain and concluded that at present there is no scientific evidence of a cause and effect relationship between the intake of L theanine and the indicated benefits 35 Supplement use Edit Tub of theanine capsules A 2020 systematic review concluded that L theanine supplementation between 200 and 400 mg per day may help reduce stress and anxiety acutely in people with acute stress but there is insufficient evidence for treatment of chronic stress It further concluded that longer term and larger clinical study is needed to clinically justify its use therapeutically 36 In 2003 the German Federal Institute for Risk Assessment Bundesinstitut fur Risikobewertung BfR objected to the addition of isolated theanine to beverages 37 38 The institute stated the amount of theanine consumed by regular drinkers of tea or coffee is virtually impossible to determine While it was estimated the quantity of green tea consumed by the average Japanese tea drinker per day contains about 20 mg of the substance there are no studies measuring the amount of theanine being extracted by typical preparation methods or the percentage lost by discarding the first infusion Therefore with the Japanese being exposed to possibly much less than 20 mg per day and Europeans presumably even less it was the opinion of the BfR that pharmacological reactions to drinks typically containing 50 mg of theanine per 500 milliliters could not be excluded reactions such as impairment of psychomotor skills and amplification of the sedating effects of alcohol and hypnotics 39 The combination of theanine and caffeine has been shown to promote faster simple reaction time faster numeric working memory reaction time and improved sentence verification accuracy 40 41 42 43 Studies have also concluded that an L theanine and caffeine combination have improved sustained attention impulsivity and cognition in children diagnosed with ADHD 44 45 46 Theanine has been reported to raise levels of brain serotonin and dopamine with possible improvement in specific memory and learning tasks 47 48 49 In brewed teabags EditA study of teabags sold in British supermarkets in 2011 found that the teabags containing the most L theanine per cup 24 mg versus 8 mg per cup were the lower quality brands containing black tea with a supermarket brand of black tea having the highest theanine content The study demonstrates that brewing time is a major determinant of the amount of l theanine extracted Addition of sugar and small quantities of milk make no significant difference while larger quantities of milk reduced the measured theanine content 50 See also Editgamma Glutamylmethylamide Green teaReferences Edit a b Scheid L Ellinger S Alteheld B Herholz H Ellinger J Henn T Helfrich H P Stehle P 2012 Kinetics of L Theanine Uptake and Metabolism in Healthy Participants Are Comparable after Ingestion of L Theanine via Capsules and Green Tea Journal of Nutrition 142 12 2091 2096 doi 10 3945 jn 112 166371 ISSN 0022 3166 PMID 23096008 a b c d D theanine C7H14N2O3 ChemSpider com Retrieved 2015 05 21 a b Theanine Pubchem Compound NCBI Retrieved 21 February 2015 Components of Gyokuro IPPODO Ippodo tea co jp Retrieved 2015 05 07 a b Sakato Y J Agri Chem Soc 1949 23 262 267 Mason R Altern amp Complementary Ther 2001 7 91 95 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 1598 1601 maintenance of normal sleep ID 1222 1737 2004 and reduction of menstrual discomfort ID 1599 pursuant to Article 13 1 of Regulation EC No 1924 2006 European Food Safety Authority EU Register on nutrition and health claims European Commission p 153 Retrieved 2021 08 10 Vuong Quan V Bowyer Michael C Roach Paul D 2011 L Theanine Properties synthesis and isolation from tea Journal of the Science of Food and Agriculture 91 11 1931 1939 doi 10 1002 jsfa 4373 PMID 21735448 a b c Desai M J Armstrong D W 2004 Analysis of derivatized and underivatized theanine enantiomers by high performance liquid chromatography atmospheric pressure ionization mass spectrometry Rapid Communications in Mass Spectrometry 18 3 251 256 Bibcode 2004RCMS 18 251D doi 10 1002 rcm 1319 PMID 14755608 How Gyokuro is Processed IPPODO Ippodo tea co jp Archived from the original on 2018 04 25 Retrieved 2015 05 07 Finger Andreas Kuhr Susanne Engelhardt Ulrich 1992 Chromatography of tea constituents Journal of Chromatography 624 1 2 309 310 doi 10 1016 0021 9673 92 85685 M PMID 1494009 Casimir J Jadot J Renard M 1960 Separation et caracterisation de la N ethyl g glutamine a partir de Xerocomus badius Separation and characterization of N ethyl g glutamine from Xerocomus badius Biochimica et Biophysica Acta in French 39 3 462 468 doi 10 1016 0006 3002 60 90199 2 PMID 13808157 Kurihara Shigekazu Shibakusa Tetsuro Tanaka Kenji AK 2013 Cystine and theanine Amino acids as oral immunomodulative nutrients SpringerPlus 2 635 doi 10 1186 2193 1801 2 635 PMC 3851524 PMID 24312747 Albrecht Jan Sidoryk Wegrzynowicz Marta Zielinska Magdalena Aschner Michael November 2010 Roles of glutamine in neurotransmission Neuron Glia Biology 6 4 263 276 doi 10 1017 S1740925X11000093 ISSN 1741 0533 PMID 22018046 a b Yokogoshi Hidehiko Kobayashi Miki Mochizuki Mikiko Terashima Takehiko 1998 Effect of theanine g glutamylethylamide on brain monoamines and striatal dopamine release in conscious rats Neurochemical Research 23 5 667 673 doi 10 1023 A 1022490806093 PMID 9566605 S2CID 24749717 a b c d Nathan Pradeep Lu Kristy Gray M Oliver C 2006 The Neuropharmacology of L Theanine N Ethyl L Glutamine Journal of Herbal Pharmacotherapy 6 2 21 30 doi 10 1300 J157v06n02 02 PMID 17182482 Kakuda T Nozawa A Sugimoto A Niino H 2002 Inhibition by theanine of binding of 3H AMPA 3H kainate and 3H MDL 105 519 to glutamate receptors Biosci Biotechnol Biochem 66 12 2683 2686 doi 10 1271 bbb 66 2683 PMID 12596867 S2CID 26585005 a b Kakuda T 2011 Neuroprotective effects of theanine and its preventive effects on cognitive dysfunction Pharmacol Res 64 2 162 168 doi 10 1016 j phrs 2011 03 010 PMID 21477654 a b Kakuda T 2002 Neuroprotective effects of the green tea components theanine and catechins Biol Pharm Bull 25 12 1513 1518 doi 10 1248 bpb 25 1513 PMID 12499631 Sebih Fatiha Rousset Matthieu Bellahouel Salima Rolland Marc de Jesus Ferreira Marie Celeste Guiramand Janique Cohen Solal Catherine Barbanel Gerard Cens Thierry Abouazza Mohammed Tassou Adrien 2017 08 16 Characterization of l Theanine Excitatory Actions on Hippocampal Neurons Toward the Generation of Novel N Methyl d aspartate Receptor Modulators Based on Its Backbone ACS Chemical Neuroscience 8 8 1724 1734 doi 10 1021 acschemneuro 7b00036 ISSN 1948 7193 PMID 28511005 S2CID 3533449 Nagasawa K Aoki H Yasuda E Nagai K Shimohama S Fujimoto S 2004 Possible involvement of group I mGluRs in neuroprotective effect of theanine Biochem Biophys Res Commun 320 1 116 122 doi 10 1016 j bbrc 2004 05 143 PMID 15207710 Sugiyama T Sadzuka Y Tanaka K Sonobe T 2001 Inhibition of glutamate transporter by theanine enhances the therapeutic efficacy of doxorubicin Toxicol Lett 121 2 89 96 doi 10 1016 s0378 4274 01 00317 4 PMID 11325559 Sugiyama T Sadzuka Y 2003 Theanine and glutamate transporter inhibitors enhance the antitumor efficacy of chemotherapeutic agents Biochim Biophys Acta 1653 2 47 59 doi 10 1016 s0304 419x 03 00031 3 PMID 14643924 Narukawa M Toda Y Nakagita T Hayashi Y Misaka T 2014 L Theanine elicits umami taste via the T1R1 T1R3 umami taste receptor Amino Acids 46 6 1583 1587 doi 10 1007 s00726 014 1713 3 PMID 24633359 S2CID 17380461 Wakabayashi C Numakawa T Ninomiya M Chiba S Kunugi H 2012 Behavioral and molecular evidence for psychotropic effects in L theanine Psychopharmacology 219 4 1099 1109 doi 10 1007 s00213 011 2440 z PMID 21861094 S2CID 13824013 Yamada T Terashima T Wada K Ueda S Ito M Okubo T Juneja LR Yokogoshi H 2007 Theanine r glutamylethylamide increases neurotransmission concentrations and neurotrophin mRNA levels in the brain during lactation Life Sci 81 16 1247 1255 doi 10 1016 j lfs 2007 08 023 PMID 17904164 Yokogoshi H Kobayashi M Mochizuki M Terashima T 1998 Effect of theanine r glutamylethylamide on brain monoamines and striatal dopamine release in conscious rats Neurochem Res 23 5 667 673 doi 10 1023 A 1022490806093 PMID 9566605 S2CID 24749717 Yokogoshi Hidehiko Mochizuki Mikiko Saitoh Kotomi 1998 Theanine induced Reduction of Brain Serotonin Concentration in Rats Bioscience Biotechnology and Biochemistry 62 4 816 817 doi 10 1271 bbb 62 816 PMID 9614715 Yokogoshi Hidehiko Kato Yukiko Sagesaka Yuko M Takihara Matsuura Takanobu Kakuda Takami Takeuchi Naokazu 1995 Reduction Effect of Theanine on Blood Pressure and Brain 5 Hydroxyindoles in Spontaneously Hypertensive Rats Bioscience Biotechnology and Biochemistry 59 4 615 618 doi 10 1271 bbb 59 615 PMID 7539642 Theanine Monograph Natural Standard Archived from the original on December 24 2014 Retrieved 30 October 2014 Everett J M Gunathilake D Dufficy L Roach P Thomas J Upton D Naumovski N 2016 Theanine consumption stress and anxiety in human clinical trials A systematic review Journal of Nutrition amp Intermediary Metabolism 4 41 42 doi 10 1016 j jnim 2015 12 308 Hidese S Ogawa S Ota M Ishida I Yasukawa Z Ozeki M Kunugi H 2019 Effects of L Theanine Administration on Stress Related Symptoms and Cognitive Functions in Healthy Adults A Randomized Controlled Trial Nutrients 11 10 2362 doi 10 3390 nu11102362 PMC 6836118 PMID 31623400 Evans Malkanthi McDonald Alison C Xiong Lora Crowley David C Guthrie Najla 2021 A Randomized Triple Blind Placebo Controlled Crossover Study to Investigate the Efficacy of a Single Dose of AlphaWave L Theanine on Stress in a Healthy Adult Population Neurology and Therapy 10 2 1061 1078 doi 10 1007 s40120 021 00284 x PMC 8475422 PMID 34562208 Type Opinion of the Scientific Committee Scientific Panel On request from European Commission Question number EFSA Q 2008 1843 EFSA Q 2008 1960 EFSA Q 2008 2334 EFSA Q 2008 2335 EFSA Q 2008 2336 EFSA Q 2008 2337 EFSA Q 2008 2443 EFSA Q 2008 2473 EFSA Q 2008 2668 EFSA Q 2008 2737 EFSA Q 2008 2738 Adopted 08 April 2011 Published 30 June 2011 Affiliation European Food Safety Authority EFSA Parma Italy Williams JL Everett JM D Cunha NM Sergi D Georgousopoulou EN Keegan RJ et al 2020 The Effects of Green Tea Amino Acid L Theanine Consumption on the Ability to Manage Stress and Anxiety Levels a Systematic Review Plant Foods Hum Nutr 75 1 12 23 doi 10 1007 s11130 019 00771 5 PMID 31758301 S2CID 208213702 The supplementation of L THE in its pure form at dosages between 200 and 400 mg day may help reduce stress and anxiety acutely in people undergoing acute stressful situations but there is insufficient evidence to suggest it assists in the reduction of stress levels in people with chronic conditions However the results of this study suggest that L THE taken during times of heightened acute stress or by individuals with a high propensity for anxiety and stress may exhibit beneficial properties via the increased production of alpha waves and decrease of glutamate in the brain a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link https www bfr bund de cm 343 getraenke mit isoliertem l theanin pdf bare URL PDF Robin B Kanarek Harris R Lieberman 2011 Diet Brain Behavior Practical Implications CRC Press pp 239 ISBN 978 1 4398 2156 5 Getranke mit isoliertem L Theanin Beverages with isolated L theanine PDF in German Bundesinstitut fur Risikobewertung August 2003 Haskell Crystal F Kennedy David O Milne Anthea L Wesnes Keith A Scholey Andrew B 2008 The effects of l theanine caffeine and their combination on cognition and mood Biological Psychology 77 2 113 122 doi 10 1016 j biopsycho 2007 09 008 PMID 18006208 S2CID 3772348 Owen Gail N Parnell Holly De Bruin Eveline A Rycroft Jane A 2008 The combined effects of L theanine and caffeine on cognitive performance and mood Nutritional Neuroscience 11 4 193 198 doi 10 1179 147683008X301513 PMID 18681988 S2CID 46326744 Bryan Janet 2008 Psychological effects of dietary components of tea Caffeine and L theanine Nutrition Reviews 66 2 82 90 doi 10 1111 j 1753 4887 2007 00011 x PMID 18254874 Kelly Simon P Gomez Ramirez Manuel Montesi Jennifer L Foxe John J 2008 L Theanine and Caffeine in Combination Affect Human Cognition as Evidenced by Oscillatory alpha Band Activity and Attention Task Performance The Journal of Nutrition 138 8 1572S 1577S doi 10 1093 jn 138 8 1572S PMID 18641209 Kahathuduwa C Wakefield S West B Blume J Mastergeorge A 2019 L theanine and Caffeine Improve Sustained Attention Impulsivity and Cognition in Children with Attention Deficit Hyperactivity Disorders by Decreasing Mind Wandering Current Developments in Nutrition 3 Suppl 1 nzz031 OR29 04 19 doi 10 1093 cdn nzz031 OR29 04 19 PMC 6574559 Kahathuduwa C N Wakefield S West B D Blume J Dassanayake T L Weerasinghe V S Mastergeorge A 2020 Effects of L theanine caffeine combination on sustained attention and inhibitory control among children with ADHD a proof of concept neuroimaging RCT Scientific Reports 10 1 13072 Bibcode 2020NatSR 1013072K doi 10 1038 s41598 020 70037 7 PMC 7403383 PMID 32753637 Anas Sohail Anas Ortiz Fernando Varghese Teresa Fabara Stephanie P Batth Arshdeep S Sandesara Darshan P Sabir Ahtesham Khurana Mahika Datta Shae Patel Urvish K 2021 The Cognitive Enhancing Outcomes of Caffeine and L theanine A Systematic Review Cureus 13 12 e20828 doi 10 7759 cureus 20828 PMC 8794723 PMID 35111479 Nathan PJ Lu K Gray M Oliver C 2015 04 20 The neuropharmacology of L theanine N ethyl L glutamine a possible neuroprotective and cognitive enhancing agent J Herb Pharmacother 6 2 21 30 doi 10 1300 J157v06n02 02 PMID 17182482 mukohmatcha 2022 03 23 お茶 緑茶 カテキンとテアニンの効果 効能まとめ一覧 日本一の八女茶専門店 向抹茶 むこうまっちゃ Mukoh Matcha Mukou Mathca in Japanese Retrieved 2022 10 02 Unno Keiko Nakamura Yoriyuki 2021 08 12 Green Tea Suppresses Brain Aging Molecules Basel Switzerland 26 16 4897 doi 10 3390 molecules26164897 ISSN 1420 3049 PMC 8401650 PMID 34443485 Keenan Emma K Finnie Mike D A Jones Paul S Rogers Peter J Priestley Caroline M 2011 How much theanine in a cup of tea Effects of tea type and method of preparation Food Chemistry 125 2 588 doi 10 1016 j foodchem 2010 08 071 Further reading EditE K Keenan M D A Finnie P S Jones P J Rogers C M Priestley 2011 How much theanine in a cup of tea Effects of tea type and method of preparation Food Chemistry 125 2 588 594 doi 10 1016 j foodchem 2010 08 071 Y Orihara T Furuya 1990 Production of theanine and other g glutamyl derivatives by Camellia sinensis cultured cells Plant Cell Reports 9 2 65 68 doi 10 1007 BF00231550 PMID 24226431 S2CID 23515765 Retrieved from https en wikipedia org w index php title Theanine amp oldid 1125482376, wikipedia, wiki, book, books, library,

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