Talk:Tryptophan

Why Supplementation?

If it's so plentiful in normal foods like eggs and meat why does supplementation with L-Tryptophan help with all of these different conditions. I don't know enough about chemistry so if someone could help me understand this I would love it. —Preceding unsigned comment added by 70.102.163.132 (talk) 04:42, 31 January 2008 (UTC)

Amino acids behave differently when they are ingested alone vs. when they are competing with other amino acids. Pocopocopocopoco (talk) 05:28, 31 January 2008 (UTC)

The Citations on this page need updated or removed

especially reguarding the triptophan content grid (14, 15) one is a PDF doc from an unverified source and the other doesn't even pertain to such a listing of various foods that contain triptophan. the PDF link (citation 15) is about chocolate additives in cigarette smoking, not triptophan. i can see why wikipedia articles get mocked in the media. —Preceding unsigned comment added by Baayne (talk • contribs) 22:11, 8 May 2008 (UTC)

Regarding the tryptophan content table, citation #14 is an exhaustive database of foods and the percentage by weight of nutrients that each food contains including the nutrient tryptophan. Hence this citation is a definitive, quantitative and, to the best of my knowledge, the most complete source of information regarding the percentage of tryptophan of various food stuffs. Most of the data in the dietary sources table came directly from this source, and if this citation were removed, the table would need to be deleted. Regarding citation # 15, while the main topic of this article as you correctly point out is cigarette smoking and not tryptophan, this article does contain background information about the levels of tryptophan in various foods. This second citation is a secondary source and contains a subset of the information contained in the first citation and therefore could be deleted. Cheers. Boghog2 (talk) 21:44, 7 June 2008 (UTC)

Table of tryptophan content in foods cannot be verified. It should be removed or replaced by another w/ data from reliable & verifiable sources.

That definitive, exhaustive nutrient database from which tryptophan content in foods had been obtained is no longer available through the link included in the reference section. If the reference is not revised I think the most sensible thing to do would be to delete the current list or try to replace it by another with reliable sources. By the way, the data of this table doesn't match by far most of the values given in the cigarette smoking article with had been also included as a complementary reference. Presumably, at least one of the two sources must be wrong.Heathmoor (talk) 18:02, 28 November 2009 (UTC)

The link was active as recently as a week ago (see Google cache). It appears that the server on which the database is hosted is temporarily down (perhaps it was overloaded by Thanksgiving related queries ;-). So I would ask you wait at least a few days before taking the drastic action of deleting the table because of a temporary outage of a database. Concerning your second point, it is not uncommon that measurements in different labs differ. There can be natural variations in the test substances, differences in extraction efficiencies, etc. This doesn't necessarily mean one or the other measurement is wrong. Again, I suggest that we wait until the USDA database is back up and we throughly recheck the numbers. Perhaps we can restrict the table to a subset of entries where the two sources closely agree. Cheers. Boghog (talk) 18:24, 28 November 2009 (UTC)

Update: USDA Nutrient Database is on-line again. Since there is a new version of the database, I have updated the link. Boghog (talk) 08:38, 29 November 2009 (UTC)

Turkey meat and drowsiness

I unfortunately don't have a source for this, but I believe it is accurate physiologically speaking... (if you can say that...) What _does_ happen when you eat a large meal of turkey (or any other large meal), is that your stomach fills up (of course) and this decreases the amount of space left in your abdominal and chest cavities for where the lungs normally expand into. Therefore you're actually decreasing the amount of air actually getting to your brain-- not to any amount critical of worry, but your body decides to save some energy, activate components of your parasympathetic nervous system, (rest and digest) and get drowsy. It's basic physiology, any B.Sc knows that... Someone should add it to the article, I'd be happy to if someone can ensure me it's not going to get instantly deleted for lack of sources. Let the health science graduates who know the science have a say. purpleidea (talk) 17:20, 5 June 2008 (UTC)

If what you say is true (referenced or not), I still can't see a reason for it it to be added to this article. As there is no reason for turkey meat specifically as opposed to any other meat, or indeed any other food, to cause this effect. If this is the mechanism by which eating large amounts of food causes drowsiness or fatigue, it'll probably be mentioned somewhere else on wikipedia, and a simple sentence with a link, rather than the long-winded explanation should suffice! Alex (talk) 20:39, 7 June 2008 (UTC)

Tryptophan and Bananas - an urban myth

Why banana is claimed to have plenty of tryptophan, when it actually has almost none? Sure the t/p-ratio is nice, but not only it has nothing to do with the actual t-content of bananas, there is also little or no explanation what this ratio actually does. --80.222.42.200 (talk) 15:32, 6 August 2008 (UTC)

I agree with the above comment. My research on the web shows that the banana as a mood elevator via it's Tryptophan content is a huge urban myth.

A banana contains about 9mg Tryptophan per 100g edible portion whereas chicken has 240mg and lentils have 232mg 88.104.193.9 (talk) 17:13, 27 March 2015 (UTC)

References

Why the POV template?

This article has a POV template from October 2008, but there is no discussion on the talk page about potential POV since August. If these issues have been resolved the POV template should be removed. If there are other issues, please raise them here on the talk page and resolve them. Tamino (talk) 08:52, 18 October 2008 (UTC)

The justification for adding the {{pov}} template in this edit was "Tagged article as biased in anticipation of reverse edits" which in my opinion is not sufficient justification. This template should only be used for alert readers to biases which may exist in the current version of the article. If the bias has been removed, then the template should be removed. Furthermore the template should not be used in anticipation of possible future biases. Adding a template to warn users of bias when in fact none exists only serves to confuse readers. Therefore I have removed the template. Cheers. Boghog2 (talk) 09:12, 18 October 2008 (UTC)

tryptophan relation to seratonin levels and osteoporosis

There is a new study which claimed to indicate that tryptophan deprivation lowered seratonin levels and reduced bone loss. http://www.nytimes.com/2008/11/27/health/research/27bone.html? —Preceding unsigned comment added by 75.171.36.132 (talk) 15:59, 27 November 2008 (UTC)

Fluorescence

The many technical details about Fluorescence were removed from this article and sent to the article where fluorescence is treated in metrology, namely the article on Fluorescence spectroscopy#Tryptophan_Fluorescence. In other words, the information will be more appreciated there where fluorescence is the topic rather than the protein. I like to saw logs! (talk) 03:51, 4 January 2010 (UTC)

5-HTP Heart Risk

The section saying that 5-HTP creates a risk of heart valve disease should say that it may have a risk, as the citations relate to direct administration of serotonin. So although this is a fairly logical conclusion, it shouldn't be written as absolute truth.174.3.107.124 (talk) 05:41, 7 March 2010 (UTC)

An interesting view on 5-HTP and heart valve disease:-

http://yarchive.net/med/5-htp.html — Preceding unsigned comment added by 84.93.186.84 (talk) 20:10, 9 July 2011 (UTC)

Wrong figure in Trp biosynthesis from chorismate

in the figure, the 3rd step involves n-(5'-phosphoribosyl)-anthranilate, the steps are alright but it's structure is inaccurate. The N of anthanilate should be directly bonded to the ribose ring, yet the figure shown has a kink, which indicates the presence of another C before connecting to the ribose ring, and is wrong.

I have also checked the Lehninge. plx replace the fig. — Preceding unsigned comment added by 203.188.72.157 (talk) 10:25, 11 September 2011 (UTC)

Yes, there does appear to be an error in the image. I have asked the creator of the image to have a look and fix it. Thanks for catching the error and reporting it here. -- Ed (Edgar181) 11:47, 11 September 2011 (UTC)

Thanks for spotting the error. The figure has now been corrected. Boghog (talk) 12:17, 11 September 2011 (UTC)

citation?

It is an essential amino acid as demonstrated by its growth effects on rats.

this could use citation — Preceding unsigned comment added by 69.146.244.19 (talk) 11:06, 22 October 2012 (UTC)

Lacose intolerance

Under the heading "Function," lactose intolerance is referred to as a disorder. This seems an odd way to describe the common conditions of all other mammals and most humans. Does the entire population of Thailand, for example, suffer from a "disorder" as a result of lacking one of the relevant mutations? It may rarely occur as a disorder, but it is otherwise the human norm. A failure to recognize its normality can cause problems in increasingly diverse urban societies. 24.7.237.175 (talk) David Harley 11/23/12 —Preceding undated comment added 17:29, 23 November 2012 (UTC)

Minor Correction in diagram for synthezing of tryptophan

Hi, This might be a major undertaking to correct, but, for what it's worth, I would like to set the record straight in pointing out that in the diagram under the header "Biosynthesis and industrial production", the last molecule in the chain has a typo and should, of course, read: "tryptophan". Safetydude (talk) 23:44, 26 November 2012 (UTC)Safetydude.

I've asked RicHard-59 to fix it at commons:User_talk:RicHard-59#File:Tryptophan_biosynthesis_.28en.29.svg. --Rifleman 82 (talk) 01:05, 27 November 2012 (UTC)

Talk about Tryptophan into Niacin

The article should mention how tryptophan can be used to make vitamin B3 niacin. — Preceding unsigned comment added by 75.102.127.173 (talk) 13:44, 31 March 2014 (UTC)

Article with cites about the Showa Denko impurities. GMO or no?

http://www.nemsn.org/Articles/truth_about_tryptophan.htm

What is the question? Jytdog (talk) 22:05, 1 June 2014 (UTC)

Molecular Formula

What's the molecular formula?
Eg: Phenylalanine has a chemical formula of C9H11NO2 but a molecular forumla of C6H5CH2CHCOOH

~ender 2014-10-06 5:58:AM MST — Preceding unsigned comment added by 71.223.87.212 (talk • contribs) 12:59, 6 October 2014 (UTC)

for the condensed formula see here Jytdog (talk) 13:07, 6 October 2014 (UTC)

That's certainly close to what I'm looking for. And, really nice information. But, I was looking to regularize the wikipedia articles, and... the condensed structural formula is not the molecular formula, and much harder to put into a purely text-based summary (that gets ripped to Google).

~ender 2014-10-06 6:18:AM MST — Preceding unsigned comment added by 71.223.87.212 (talk • contribs) 13:18, 6 October 2014 (UTC)

if you cannot get to the exact thing you are looking from what i gave you, you should maybe reconsider doing what you are considering. Also, the chembox instructions tell us to give the molecular formula. making the kind of systematic change that you are thinking of making, is something you should discuss at the chembox template talk page before you do, or on the talk page of the guideline for using chemboxes. template is Template:Chembox; guideline is Wikipedia:Chemical infobox Jytdog (talk) 14:00, 6 October 2014 (UTC)

Examine the other amino acids if you have a problem with wikipedia's inconsistency. Merely trying to get the these articles into a similar state. Perhaps we should treat it like wikipedians do for other articles, and instead delete the information on the articles which do have that information :)

~ender 2014-10-06 12:34:PM MST — Preceding unsigned comment added by 71.223.87.212 (talk)

i noticed that you deleted the unsigned template i added to your posting. please actually sign your posts using four tildas. the reasons for this are many and not signing your posts is considered disruptive behavior and will get you blocked, and if you persist, banned. what you are doing is not sufficient. please see Wikipedia:Signatures. Jytdog (talk) 14:05, 6 October 2014 (UTC)

Tryptophan and aging

I would like to point out that the scope of this article is wider than WP:MED, it also includes WP:MCB. As long as it is made clear that the studies are in animals, this should be fair game to include a section on tryptophan and aging. A good secondary source that discusses the evidence is here: PMID 23562344. Boghog (talk) 14:53, 29 December 2014 (UTC)

i really struggle with this boghog. at the end of the day, nobody cares whether mice live longer. the work in mice, and the reporting of it, only matter because people are trying to understand human health, and, i would guess, longevity freaks would read this and say "oh, i will for sure avoid tryptophan going forward" ugh. Jytdog (talk) 15:22, 29 December 2014 (UTC)

Some people are also interested in basic research. Of course, the reason why this research is funded is that it may eventually be applied to improve human health. The attitude that we should not include such information since it might be misinterpreted by some people amounts to censorship. Boghog (talk) 15:48, 29 December 2014 (UTC)

nope, censored is irrelevant to this. Please see WP:MEDRS and WP:MEDMOS. We don't provide the public with information about health based on animal studies. Jytdog (talk) 16:48, 29 December 2014 (UTC)

Wikipedia is the sum of all human knowledge. Animal studies are part of that knowledge. WP:MEDRS only applies to content that is within the scope of WP:MED and as I have stated above, the scope of this article is wider than WP:MED. Boghog (talk) 17:26, 29 December 2014 (UTC)

While we are quoting Wikipedia guidelines, I would suggest that you read the WP:MEDANIMAL section of WP:MEDRS which reads in part Where in vitro and animal-model data are cited on Wikipedia, it should be clear to the reader that the data are pre-clinical, and the article text should avoid stating or implying that the reported findings hold true in humans. So even MEDRS allows animal studies as long as it is carefully worded. Boghog (talk) 18:50, 29 December 2014 (UTC)

ok, so based on secondary sources, and no UNDUE weight, and properly couched. Jytdog (talk) 20:42, 29 December 2014 (UTC)

Wrong structure

The first structure on the right hand side is wrong with an extra carbon. https://en.wikipedia.org/wiki/Tryptophan#/media/File:L-Tryptophan_physiological_ACS.png The second structure is right. Why are there 2 pictures of tryptophan, with the second being called ball and stick model while it is clearly not? — Preceding unsigned comment added by Hieniemic (talk • contribs) 16:00, 23 December 2015 (UTC)

In psychiatry or in neurology?

The article reads:

Tryptophan affects brain serotonin synthesis when given orally in a purified form and is used to modify serotonin levels for research in psychology.[33]

Unfortunately I do not have access to the source text. It however appears unlikely to me that psychology was the intended word in this context. 76.10.128.192 (talk) 05:46, 7 January 2016 (UTC)

I have simply removed "in psychology", the reference is about pharmacology, neurology, perhaps psychiatry. PaleoNeonate (talk) 11:29, 15 March 2017 (UTC)

Regulatory

The drug laws in Europe are very strict, particularly with the Indication "depression" or "insomnia", and L-tryptophan (or melatonin) is available as a prescription drug only. Its use as a dietary supplement in non-approved products is illegal, with a few exceptions in the Netherlands and the UK where non-registered supplements are much more tolerated. I am not necessarily an advocate of strict regulation but it is interesting to see how well-controlled the continental Europeans are approaching this. Osterluzei (talk) 06:57, 16 February 2016 (UTC)

Crystal structure of L-tryptophan

I was looking for the crystal structure of pure L-tryptophan to illustrate this article and found that it had only recently been determined: G. M. Day and co-workers, Acta Cryst. (2012). B68, 549-557. That paper notes that the crystal structures of the pure forms all the other standard L-amino acids apart from L-lysine have been determined.

Is there consensus yet on how to show the 3D structures of amino acid molecules? The issue is the zwitterionic forms are more realistic but confusing for some readers, whereas the neutral forms are simpler but do not exist in reality (perhaps with the exception of some strange gas-phase situation). We have a neutral structure, File:L-Tryptophan - L-Tryptophan.svg, in the Chembox at the moment, but that form is more of a concept than a real structure because one of the acid groups would protonate the amine forming a zwitterion.

Has this dilemma been settled elsewhere?

--Ben (talk) 11:09, 27 April 2016 (UTC)

Tryptophan in milk

The value "0,08" (if You calculate 2.34 % from 3.22 g, You get exactly 75 mg) is definitely wrong; searching the USDA database leads to 0,046g =(46 mg). --Cvf-ps (talk) 14:30, 4 December 2016 (UTC)

Data table inaccuracy

Using data from nutritiondata.self.com, ground beef has a tryptophan to protein ratio of approximately 0.5%, rather than the table's listing for beef of 1.12%. The entry for turkey does seem accurate though, at 1.11%. I couldn't find any specific data on tryptophan content from the cited USDA database. — Preceding unsigned comment added by 63.155.229.130 (talk) 17:51, 14 December 2017 (UTC)

Inaccurate data table

Using data from nutritiondata.self.com, ground beef has a tryptophan to protein ratio of approximately 0.5%, rather than the table's listing for beef of 1.12%. The entry for turkey does seem accurate though, at 1.11%. I couldn't find any specific data on tryptophan content from the cited USDA database. Thus, turkey contains at least twice as much tryptophan per total protein than ground beef.

63.155.229.130 (talk) 18:00, 14 December 2017 (UTC)

The problem is that the USDA site has completely been revised so one is no longer able to do the same type of searches that one previously could. I am certain that the numbers in the table were correct as of 2009-11-29 since I personally checked them. Unfortunately as of 14 December 2017, one can no longer do a similar check in the on-line USDA database. I have also checked the WayBack machine and one cannot reproduce the search results using that source. It appear that one can obtain the percentage of tryptophan in the total weight of beet and the total weight of protein in total weight of beet and from that calculate the percentage of tryptophan from beet protein. This type of calculation is allowed per WP:CALC. I don't have time to do this right now, but will look again this weekend. Boghog (talk) 21:30, 14 December 2017 (UTC)

In the current USDA Food Composition Database, one can list two nutrients (e.g., protein and tryptophan) at the same time and download the results in a csv file and import into a spread sheet for calculations. It turns out that the database contains many values for beef. For example somewhat different values are listed for different cuts of beef and for different preparation methods. Ditto for turkey. Listed below are the averages:

USDA Food Composition Database

Food	Tryptophan/Protein (%)	Standard Deviation	Number of measurements
Beef	0.98	0.24	944
Turkey	1.03	0.18	203

Hence according to the USDA Food Composition Database, the percentage tryptophan in beef or turkey protein is almost equal and the numbers are very similar to what is current listed in the article table. Digging further into the numbers, it appears that the percentage of tryptophan in ground beef is lower (~0.5%) than for some other cuts of beef. However the current table does not specify which type of beef, hence I think the numbers in current table are reasonably accurate. Boghog (talk) 06:39, 16 December 2017 (UTC)

Boghog (talk) 06:39, 16 December 2017 (UTC)

Corrections to first paragraph of the article

It says that "Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a non-polar aromatic amino acid". The "α-carboxylic acid group" is incorrect, it should be simply "carboxylic acid group" without the"α". The "carboxylic acid group" is the primary functional group and the positions of the other functional groups such as the amino group or the indole side chain are given relative to the carboxylic acid group. The "α-amino group" is correct, because the amino group is in the "α" position relative to the carboxylic acid group. This means that it is attached to the C atom adjacent to the carboxylic acid C atom. Secondly, making it a non-polar aromatic amino acid" is not correct. It is aromatic, but not completely non-polar. Instead, you could maybe say "making it a fairly non-polar aromatic amino acid" or "making it an aromatic amino acid that is far less polar than most other α-amino acids found in protein". Note that phenylalanine is also an aromatic α-amino acid that should also be fairly non-polar (or have a fairly low polarity). 155.240.161.3 (talk) 08:36, 14 May 2019 (UTC) Mike Philpott

L-

is L-tryptophan that same as tryptophan? I can't see anything on the page but they seem to be interchangeable terms. please remember people might come here after reading a bottle of supplements or an article and not have chemistry knowledge. 84.67.13.0 (talk) 16:15, 29 March 2023 (UTC)

Wrong structure 2

Chinese, Japanese, and Spanish articles show right structure, though this English article shows wrong pictures in which the under Nitrogen atom is connected to 3 (not 2) Hydrogen atoms and I cannot find Carboxy group around there. In French article there are no 3D pictures. I am sure these pictures should be copied from other language articles, or just get removed. 240B:C020:4B1:55CC:3D8D:9B28:97D5:C2BC (talk) 13:07, 14 August 2023 (UTC)

Inaccurate data table

g/100 g is probably the wrong unit for tryptophan content. Should probably be mg / 100 g 194.207.180.128 (talk) 19:55, 8 March 2024 (UTC)

Don't think so - the values stated are consistent with Tryptophan/protein %, so what makes you think there is a 1000-fold error? Plantsurfer 20:35, 8 March 2024 (UTC)