Talk:Theanine/Archive 1

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Is L-Theanine also known by another name? I having trouble finding it at GNC's or CVS pharmacies. --JoelM do a GOOGLE search and you will find it everywhere..

I think its a relatively new discovery, either that or the tea companies have just started to exploit it all of a sudden because I'm constantly hearing it on the radio over here at the moment. Like tea companies advertising it, telling you to drink their tea because of it. Which is ironic considering that it was always in the tea.. so in reality they're just aiming for a placebo effect? Because lets face it, everyone has had tea at least once in their life (well at least most people.) But now they think that if they tell us that tea contains this special ingredient, everyone will start buying it. Which is true, but a dodgy marketing scheme. Javsav 16:29, 28 August 2006 (UTC)

This isn't really a question/concern that should be posted here. That said; It is generally accepted L-Theanine was discovered in 1949/1950 (although exact date and discoverer are to be confirmed/proved). Because L-Theanine can be isolated, it can be delivered in a variety of formats and strengths. The average amount of L-Theanine in green tea is unlikely to have changed (from the average of 1.4% by weight), unless it is supplemented by the tea marketers.Buckfizzed (talk) 22:19, 11 November 2014 (UTC)sm

http://www.accessdata.fda.gov/scripts/fcn/fcnNavigation.cfm?filter=Theanine&sortColumn=&rpt=scogsListing It is not on the the GRAS or EAFUS list. The FDA has never sanctioned it as a food additive — Preceding unsigned comment added by 128.171.212.47 (talk) 00:29, 13 December 2012 (UTC)

Correct, according to an FDA response November 5 2010 http://www.fda.gov/Food/FoodIngredientsPackaging/GenerallyRecognizedasSafeGRAS/GRASListings/ucm235932.htm to a company's claimed GRAS for theanine, concluding (in a non-committal manner) "the agency has no questions at this time regarding Blue California’s conclusion that L-theanine is GRAS under the intended conditions of use", theanine does not have GRAS status granted by the US FDA.Kdarwish1 (talk) 10:35, 8 January 2013 (UTC) Unbalanced scales.svg

The link provided in the paragraph above is no longer available and the statement above that L-Theanine does not have GRAS status is false. As such, it should be removed. Please review the link below as proof - http://www.fda.gov/downloads/food/ingredientspackaginglabeling/gras/noticeinventory/ucm269524.pdf (page 5, marked 000007) or http://www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/NoticeInventory/ucm410002.htm. To be clear, the FDA does not provide 'GRAS' status, rather it reviews the evidence provided to it and determines if it agrees with the evidence or if further information should be provided or questions answered. Assuming the evidence is scientifically reliable and robust, the FDA will agree with the provider of the information that the ingredient is 'GRAS'. As an example, please read the conclusion in this link - http://www.fda.gov/food/ingredientspackaginglabeling/gras/noticeinventory/ucm410002.htm Buckfizzed (talk) 22:19, 11 November 2014 (UTC)sm

This article misrepresents both the statistical power and the qualitative nature of scientific research with respect to the use of Theanine as a agent to modify psychological dimensions in humans. The cited research is overwhelmingly weighted in animal models and from journals of tertiary repute. There is no level of clinical evidence on any of the acceptable levels of evidence based medicine cited in this article.

A simple search finds numerous animal and human trials. Granted some of the trials do not have large 'n' values, however they are on humans and do show clear evidence of efficacy for particular conditions/concerns (not all). It is also important to remember the amino acid L-Theanine is considered a 'food' (perhaps better described as a food supplement or food additive), it is not a 'prescribed medicine' and as such, does not need to meet the same standard of proof as a 'prescribed medicine'. The same 'lack of evidence' could be used on a multitude of 'foods' that claim health benefits: from coffee to olive oil to beetroot. Examples of the research are included below:

· http://www.ncbi.nlm.nih.gov/pubmed/18296328

· L-theanine. Memorial Sloan-Kettering Cancer Center website. Available at: http://www.mskcc.org/mskcc/html/69285.cfm . Updated December 10, 2010. Accessed August 15, 2011.

  • Sugiyama T, Sadzuka Y. Combination of L-theanine with doxorubicin inhibits hepatic metastasis of M5076 ovarian sarcoma. Clin Cancer Res . 1999;5(2):413-416.
  • Sadzuka Y, Sugiyama T, Sonobe T. Improvement of idarubicin induced antitumor activity and bone marrow suppression by L-theanine, a component of tea. Cancer Lett . 2000;158(2):119-124.
  • Juneja LR. Suntheanine and its relaxation effect in humans. Trends in Food Science & Tech . 1999;10;199-204.
  • Nobre AC, Rao A, Owen GN. L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr . 2008;17 Suppl 1:167-168.
  • Park SK, Jung IC, Lee WK, et al. A combination of green tea extract and l-theanine improves memory and attention in subjects with mild cognitive impairment: a double-blind placebo-controlled study. J Med Food . 2011;14(4):334-343.
  • Ritsner MS, Miodownik C, Ratner Y, et al. L-theanine relieves positive, activation, and anxiety symptoms in patients with schizophrenia and schizoaffective disorder: an 8-week, randomized, double-blind, placebo-controlled, 2-center study. J Clin Psychiatry . 2011;72(1):34-42.
  • Giesbrecht T, Rycroft JA, Rowson MJ, De Bruin EA. The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness. Nutr Neurosci . 2010;13(6):283-290.
  • Einöther SJ, Martens VE, Rycroft JA, De Bruin EA. L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness. Appetite . 2010;54(2):406-409.
  • Owen GN, Parnell H, De Bruin EA, Rycroft JA. The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutr Neurosci . 2008;11(4):193-198.
  • Haskell CF, Kennedy DO, Milne AL, Wesnes KA, Scholey AB. The effects of L-theanine, caffeine, and their combination on cognition and mood. Biol Psychol . 2008;77(2):113-122.
  • Kimura K, Ozeki M, Juneja LR, Ohira H. L-Theanine reduces psychological and physiological stress responses. Biol Psychol . 2007;74(1):39-45.
  • Miyagawa K, Hayashi Y, Kurihara S, Maeda A. Co-administration of l-cystine and l-theanine enhances efficacy of influenza vaccination in elderly persons: nutritional status-dependent immunogenicity. Geriatr Gerontol Int . 2008;8(4):243-250.

Theanine research

Does anyone know any specifics about theanine's neuropharmacological properties? All I could find was one reference to "micromolar affinities" to several neurotransmitters. However, I'm sure there have been studies that give specific its particular neurochemical interactions. Jolb 20:06, 9 February 2007 (UTC)

Caffeine buzz

Someone put this in: It is theorized that the GABA-binding properties of theanine reduce the caffeine buzz delivered in black tea versus that of coffee. Of course, there was no citation, so I put a {{cn}} next to it. It was sitting there for a while, so I decided to do some research on this, and I found the following:

The objective of this study was to determine the effect of caffeine level in tea and coffee on acute physiological responses and mood. Randomised full crossover design in subjects after overnight caffeine abstention was studied. In study 1 (n = 17) the caffeine level was manipulated naturalistically by preparing tea and coffee at different strengths (1 or 2 cups equivalent). Caffeine levels were 37.5 and 75 mg in tea, 75 and 150 mg in coffee, with water and no-drink controls. In study 2 (n = 15) caffeine level alone was manipulated (water, decaffeinated tea, plus 0, 25, 50, 100, and 200 mg caffeine). Beverage volume and temperature (55 degrees C) were constant. SBP, DBP, heart rate, skin temperature, skin conductance, and mood were monitored over each 3-h study session. In study 1, tea and coffee produced mild autonomic stimulation and an elevation in mood. There were no effects of tea vs. coffee or caffeine dose, despite a fourfold variation in the latter.

(Quinlan P, Lane J, Moore K, Aspen J, Rycroft J, O'Brien D (2000). "The acute physiological and mood effects of tea and coffee: the role of caffeine level". [1])

Therefore, I'm going to remove sentence. Jolb 19:36, 14 February 2007 (UTC)

You should really look at what physiologic responses they measured. A lot of times studies like this are either done poorly, or they only look at a narrow spectrum of measurable variables. If compounds aside from caffeine are psychoactive in green tea, then some measurements will pick these up on the clinical level while others won't...--Xris0 04:29, 17 August 2007 (UTC)

Contradiction

I've added a contradiction template, because the article says that L-theanine increases serotonin levels (and cites a study), but then says it lowers serotonin levels (and cites a study). So which is it? or is something missing from the article such as spontaneous hypertension causing abnormally high levels of serotonin (in which case, the article should mention it). --Mark PEA 10:39, 9 March 2007 (UTC)

I noticed that before, but I thought it maybe had something to do with spontaneous hypertension? I decided to let it go and trust the person who added that. However, when you added the contradiction tag, I did some research.

Antioxidant activity of 5-hydroxytryptophan, 5-hydroxyindole, and DOPA against microsomal lipid peroxidation and its dependence on vitamin E.

* Cadenas E, Simic MG, Sies H.
Department of Pathology II, University of Linkoping, Sweden.
The antioxidant capacity of 5-hydroxy-tryptophan, 5-hydroxy-indole, and DOPA (3,4-dihydroxy-phenylalanine) was tested in the Fe-induced lipid peroxidation of liver microsomes of normal- and vitamin E-deficient rats, using ascorbate as a reductant. Lipid peroxidation was monitored as low-level chemiluminescence, indicative of generation of electronically-excited states arising from the recombination of secondary lipid peroxyl radicals. The lag phase (tau 0) preceding the rise in chemiluminescence intensity was used as indicator of antioxidant efficiency, in the absence (tau 0) and the presence (tau) of these polar compounds. The increase in duration of the lag phase exerted by these hydroxy compounds was expressed and quantified as the relationship: tau-tau 0. The tau-tau 0 values were considerably higher in the presence of vitamin E and almost negligible in the absence of tocopherol. It is postulated that the observed increased protection against lipid peroxidation by the above 5-hydroxy derivatives is displayed in a fashion dependent on the presence of vitamin E and probably involving recovery of the chromanoxyl radical by means of an electron-transfer process.
PMID: 2498167 [PubMed - indexed for MEDLINE]
The study really has no relevance here, but it clearly says that serotonin (5-hydroxy-tryptophan) is completely different from 5-hydroxy-indole. Jolb 13:40, 9 March 2007 (UTC)
Ah right, I understand now. Of course, serotonin is 5-hydroxy-indole-ethyl-amine, and I didn't have access to the full article, so assumed it meant biochemicals that were homologous 5-hydroxyindole, such as serotonin, that's why I was confused and added the contradict tag, but now that the serotonin statement has been removed it makes sense now. --Mark PEA 18:09, 9 March 2007 (UTC)

Occurrence

It would be nice to have a section which shows the theanine content ranges of tea and other beverages, for comparison. I've seen supplements and theanine-infused juice drinks already appearing in supermarkets.

--BadZen 15:09, 7 May 2008

Question about categorization

Might it be appropriate to categorize this page indicating this chemical has psychoactive properties? Emesee (talk) 06:24, 6 August 2008 (UTC)

I agree with this idea. Anyone else? Svadhisthana (talk) 03:49, 11 August 2008 (UTC)

Yeah, it is psychoactive, why not go for it?--Metalhead94 (talk) 00:26, 25 August 2008 (UTC)

Unclear wording

Theanine has been shown to reduce mental and physical stress, may produce feelings of relaxation and improves cognition and mood when taken in combination with caffeine.

This sentence is both grammatically incorrect and ambiguous. Which claims do the condition "when taken in combination with caffeine" apply to? If it only applies to the last one, the sentence should be reworded: "Theanine has been shown to reduce mental and physical stress and may produce feelings of relaxation. It may also improve cognition and mood when taken in combination with caffeine." If it applies to the last two claims, then it should be reworded along these lines: "Theanine has been shown to reduce mental and physical stress, and when taken with caffeine it may also produce feelings of relaxation and improve cognition and mood." In this last example, the conditional phrase is placed at the beginning of the clause to show that it applies to everything following it. If the condition applies to all three claims, then this wording might be better: "When taken in combination with caffeine, Theanine has been shown to reduce mental and physical stress, produce feelings of relaxation, and improve cognition and mood." Any help? svadhisthana (talk) 20:44, 17 August 2008 (UTC)

5-hydroxyindoles?

Does anyone know what 5-hydroxyindoles are and what they do? There's little use explaining that they are reduced by theanine without also explaining what they are. svadhisthana (talk) 20:44, 17 August 2008 (UTC)

For future reference, here is some research regarding 5-hydroxyindoles and their biochemical roles.

svadhisthana (talk) 22:13, 17 August 2008 (UTC)

Pronunciation?

How is "theanine" pronounced? Thanks! - Matt24 (talk) 16:58, 14 October 2008 (UTC) Thee-an-ine (where the 'i' sounds like an 'e' as in magazineBuckfizzed (talk) 02:59, 12 November 2014 (UTC)sm)

Theanine lowers Serotonin (does not increase as in article)

http://www.ncbi.nlm.nih.gov/pubmed/9614715?ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum —Preceding unsigned comment added by 88.156.96.9 (talk) 11:02, 5 January 2009 (UTC)

Theanine and l-theanine

The body of the article starts talking about l-theanine without defining it or telling its relation to theanine. If it is some known chemical prefix, it should be said anyway. AstroNomer (talk) 17:36, 9 March 2009 (UTC)

I added a description in parentheses after the first the first instance of "L-theanine" to clear up any confusion. L- is an abbreviation explaining the chirality of the molecule in question - in this case, not a direct levorotary isomer of theanine but merely referring to its stereochemistry in relation to one of the enantiomers of glyceraldehyde. I didn't think it was appropriate to include all the gritty details of this unless a Chemistry section is added to the theanine article.165.166.83.200 (talk) 19:50, 27 October 2009 (UTC)
Excuse me? Did you just say there are no L- or D-sided versions of theanine molecule? Why is it called l-theanine then? 84.251.176.25 (talk) 14:30, 19 May 2011 (UTC)

Non-sequitur?

"Because it can enter the brain, theanine has psychoactive properties."

Water and glucose can enter the brain... —Preceding unsigned comment added by 90.193.28.220 (talk) 21:48, 13 April 2009 (UTC)

And glucose consumption affects the brain, as one would expect. I recently ran into a study where glucose consumption caused an increase in 'willpower' as measured by readiness to engage in wearying (but easy) tasks. --Gwern (contribs) 00:04 10 October 2010 (GMT)

Immune system section

Someone should either find more sources for the proposed immune system benefits of theanine or delete the entire section at the end. The cited study is comparing the immune system of coffee drinkers to tea drinkers - not a controlled study with theanine alone. That makes it inconclusive for the purpose of evaluating theanine on its own. These effects could be explained by any one of the compounds present in tea and absent in coffee, or vice versa. 165.166.83.200 (talk) 19:36, 27 October 2009 (UTC)

There is no link between the paper cited [17] and the claim. Immune memory is not memory in the cognitive sense. Where is the mention of the hypothalamus in [17]??? Regardless, it would be the hippocampus. This is sloppy at best. —Preceding unsigned comment added by Ysgadbois (talk • contribs) 00:00, 17 March 2010 (UTC)

Removed section May 2017, as no newer literature in support of immune function and the initial literature was one small human trial. David notMD (talk) 13:20, 10 May 2017 (UTC)

History

"In 1950 the Tea laboratory of Kyoto successfully separated theanine from Gyokuro leaf, which has the highest theanine content among all teas."

So, how exactly was theanine isolated? This makes it sound as if it were some rare X-factor which had been deduced through unknown other methods, and they went looking in the richest lodes and finally found it. Which sounds a bit unlikely to me. --Gwern (contribs) 00:03 10 October 2010 (GMT)

Dosage

Studies involving tea (with a dosage of something like 20 mg) cannot produce results that can be meaningfully extrapolated to the typical 100-400 mg dosage range used for dietary supplementation. Once again, people are using what appears to be an unstudied substance in the hope of self-improvement. I'm using 300 mg myself and notice a difference, but that's hardly science and my experience cannot be a recommendation for others. If studies of realistic supplement dosage levels have been done, they should be cited. If not, that lacking should be stated. Otherwise, the article gives a false support to the overgeneralizations commonly made concerning this chemical by those who would profit from its sale. David Spector (talk) 01:11, 7 January 2011 (UTC)

Nootropic

Should teanine be considered a nootropic? If so, there are changes to be done, like including the nootropics table. 189.68.15.67 (talk) 02:37, 24 September 2011 (UTC)

Modification to Refernces

184.162.96.181 (talk) 19:18, 10 May 2012 (UTC) changed link to footnote/reference '12' (neuroprotective effects of l-theanine wrt to glutamate exictotoxicity); original link is now a dead-link; changed this to a link on the National Institutes of Health website where the same white paper can still be found.184.162.96.181 (talk) 19:18, 10 May 2012 (UTC)

Primary vs Secondary Sources

I noticed that the article is based mainly on primary rather than secondary sources. Many of the studies mentioned were rat studies or small (and rather shoddy) human trials that lacked adequate controls. An article on a subject like this should rely on secondary medical sources (ie, reputable medical organizations; reliable reviews in good clinical journals, etc.) that have analyzed and interpreted the significance of the research. See WP:MEDREV. Rhode Island Red (talk) 21:52, 3 July 2012 (UTC)

Same still applies in 2017 - small clinical and pre-clinical studies, and no good reviews. David notMD (talk) 13:15, 10 May 2017 (UTC)

This sounds like nonsense

What on earth does this sentence mean? "More specifically, this compound is called L-theanine, being the L- amino acid (not to be confused with a levorotatory enantiomer)." Although I am not a biochemist, my understanding of L-amino acids is that they are indeed levorotary enantiomers. So what does this sentence mean?--Filll (talk | wpc) 21:22, 31 October 2012 (UTC)

They are referring to the difference between an L-molecule and an l-molecule. An l-molecule is a levorotary enantiomer (polarizes light counter-clockwise). An L-molecule is structurally more similar to L-glyceraldehyde. I agree with you that the note should be removed. I think it would be more appropriate to just link the capital L to the correct section of the chirality article. Wakebrdkid (talk) 22:18, 31 October 2012 (UTC)

Chemical Formula

I think there is an error in the chemical formula for Theanine (too many H's)....H14 shouldn't it be H4 ...see diagram.

--69.19.14.22 (talk) 14:34, 17 July 2014 (UTC)Ken Coulon

The diagram and the chemical formula appear to be both correct. The diagram is a skeletal formula in which many of the hydrogen and carbon atoms are implicit. -- Ed (Edgar181) 15:06, 17 July 2014 (UTC)

Significant edits performed, and what could not be fixed in 3 hrs received tags

See the edit summaries for most changes made. Could not begin to address the closing two bioactivity sections, which are based substantially on primary sources, and are therefore overly positive (exception, the statements on the EC's report on theanine additives in beverages). The closing two are becoming hodgepodges of positive, primary-source derived claims for these supplements, which necessarily reflect OR/bias in their selection (rather than secondary source-derived authoritative statements of the current preponderance of opinion). I invite the earlier editors adding the purely positive pharmacologic and supplement claims (i) to find secondary sources, and re-edit to reflect the section content to reflect the secondary source descriptions, (ii) remove most of the primary sources, to "Further reading" or entirely, and (iii) look carefully at those same and other sources for clear statement regarding careful dosing, scope of therapeutic value, and potential off-target effects, interactions, and contraindications. Until the closing sections are sourced from secondary sources, and do not reflect the current clear positive editorial bias (again, EC report-type content excepted), the tags regarding scientific POV and poor sourcing should remain. Cheers. Le Prof 71.239.87.100 (talk) 23:48, 17 August 2014 (UTC)

I concur on all points. Rhode Island Red (talk) 00:38, 20 October 2014 (UTC)
Agreed. The only reliable secondary reference I found for L-theanine is from a monograph from Natural Standard (not freely publicly available). I am new here but would like to add a reference to Natural Standard and summarize some of the findings that are there including their ratings of the evidence in primary literature. Maybe that can be a jumping off point to clean up a lot of the dubious claims here that are only supported by weak primary literature. Blaise Hamel (talk) 03:28, 30 October 2014 (UTC)

Q: Why does what is essentially a food supplement have to have full medical/peer reviewed articles as references? I'm pretty sure the health benefits of food products such as olive oil, beetroot juice or the like don't have these requirements.Buckfizzed (talk) 03:10, 12 November 2014 (UTC)

B - Actually, yes they do. When health claims are made for foods and food components, rigorous evidence is required. The FDA-approved health claim for beta-glucan from oats and barley lowering cholesterol is supported by dozens of published human trials. David notMD (talk) 13:17, 10 May 2017 (UTC)

Chemistry

I just made a few edits; please don't revert them all if you don't like just some of them. I thought it would be less confusing if we went with L- and D- prefixes rather than L- and D- as often as possible. A particular pet hate was the "Amino acid racemization in aqueous media"... sentence; the way it was bracketed implied that the previous sentence about predominating D-enantiomer could have come from this process.

A matter of opinion: edits on chemical nuances by those unskilled in chemistry can be unhelpful and lead to falsities. See the C14/C4 debate above? FlowerFaerie087 (talk) 00:56, 14 February 2015 (UTC)

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Assessment comment

The comment(s) below were originally left at Talk:Theanine/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

The theanine entry uses reference #4 to indicate that theanine "may produce feelings of relaxation", but the study cited indicates that it only produces these feelings in persons who are not already stressed. The study states that "neither L-theanine not alprazolam demonstrate any acute anxiolytic effects under conditions of increased anxiety in the AA model".

Last edited at 21:37, 21 February 2008 (UTC). Substituted at 08:31, 30 April 2016 (UTC)

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