Talk:Monosodium glutamate

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Wrong molecular structure[edit]

The molecular structure shown in the chembox is wrong. In crystalline monosodium glutamate monohydrate (the form used as flavoring, Aji-no-Moto) and in near-neutral solutions, the glutamate anion is a zwitterion: both carboxyl groups have lost their protons and are negatively charged, while the amino group has an extra proton and a positive charge. The sodium cation is not bound to the glutamate, but alternates with it in the crystal lattice, and is detached from it in solution.[1] --Jorge Stolfi (talk) 01:14, 18 February 2017 (UTC)

I have removed the image that shows the sodium atom covalently bonded to the oxygen atom. As for the skeletal formula, this is an issue that has come up occasionally over the years - how to appropriately depict amino acids. The protonation state of the amine and carboxylic acid groups can vary according to many factors such as whether it is in solution or in a solid or what the pH of the solution is. The way that Wikipedia has generally handled it is to prioritize depicting amino acids as amino acids, not as zwitterionic ammonium carboxylates (for example), and then later on discussing the complexities of pH-dependent protonation states. Skeletal formulas are shorthand approximations; they are not intended to represent all the complexities of molecular bonding. If you wish to include information about the crystal structure of monosodium glutamate dihydrate (which I think would be a nice addition), I would strongly recommend adding a new section of text in the main body of the article with appropriate imagery there, rather than replacing the image in the infobox. -- Ed (Edgar181) 14:35, 22 February 2017 (UTC)


  1. ^ Chiaki SANO, Nobuya NAGASHIMA, Tetsuya KAWAKITA, Yoichi IITAKA (1989), "Crystal and Molecular Structures of Monosodium L-Glutamate Monohydrate". Analytical Sciences, volume 5, issue 1, pages 121-122. doi:10.2116/analsci.5.121

Proposal to move of the health effects material to a separate article[edit]

I gather that the discussion of the "Chinese Reataurant Syndrome" and other health-related subtopics was moved to this article from Glutamate flavoring, with the excuse that readers looking for these sub-topics would be likely to come to this article first. But that is inadequate, because almost all of the discussion on those sub-topics applies to glutamate flavorings in general, including natural glutamate sources. Indeed, part of that discussion had to be left there, resulting in duplication and separation of stuff that should be discussed together.
Rather than moving the material back to Glutamate flavoring, I propose to create a separate article about "Health effects of glutamate" (or some such title), which would be clearly linked to from both articles (and from articles on glutamic acid and other glutamate salts, like disodium glutamate and calcium glutamate. The links could even be in the "hat notes" at the top of the pages. What do you think? --Jorge Stolfi (talk) 01:30, 18 February 2017 (UTC)

Chinese Restaurant Syndrome etc relevant to MSG, as far as I know, not to other glutamates Cathry (talk) 10:07, 18 February 2017 (UTC)
Free glutamate is free glutamate, whatever the salt used to get it into food. Still, this is the compound popularly associated with negative effects, despite the paucity of evidence. --tronvillain (talk) 14:00, 18 February 2017 (UTC)
Are sodium chloride, hydrochloric acid and potassium chloride same compound with same properties? Cathry (talk) 17:56, 18 February 2017 (UTC)
If free chlorine in solution was the relevant concern, then pretty much, yeah. Nothing on this page seems to suggest that it's the combination with sodium that's making the difference - it's almost always free glutamate that's given the blame (see the "Excitoxicity" section). --tronvillain (talk) 19:49, 18 February 2017 (UTC)
If something absent at this page, the possibility is the poor quality of this page. And where is solution when someone eating sausage with MSG? Cathry (talk) 23:32, 18 February 2017 (UTC)
In the moist sausage, the MSG is already dissoved, so there is no MSG anymore -- only sodium ions (that also come from salt, sodium nitrite, and possibly other aditives) and glutamate ions. And even if you eat dry MSG from the can, as soon as it dissolves in your saliva it dissociates into sodium ions and glutamate ions. --Jorge Stolfi (talk) 23:46, 20 February 2017 (UTC)
What is moist sausage? Anyway give link to sources, please. Cathry (talk) 11:34, 21 February 2017 (UTC)
A sausage that is not moist would be harder than dry salami and beef jerky. Sausages that you can chew have enough moisture to dissolve all the MSG (and all the salt, and all the nitrite) that were added to it. It would be pointless to add so much MSG that it would not dissolve already in the cooked sausage.
Have you ever seen and tasted pure MSG? You can usually find it among Oriental groceries in markets (Aji-no-moto is the classic brand), or sometimes in shakers on the tables of Oriental restaurants.
The dissociation of salts in solution is very basic high-school chemistry. Check the Wikipedia article on salt (chemistry) if you need sources on that. --Jorge Stolfi (talk) 01:34, 22 February 2017 (UTC)
Solid foods are not solutions. So, you can't provide proper links. Note also nearly every pubmed article about health concerns uses MSG term. Cathry (talk) 03:24, 22 February 2017 (UTC)
As I explained already, very few "solid" foods are completely solid. Hard candy and sugar qualify; roasted peanuts and almonds, parmesan cheese, "dry" salami, crackers -- are close enough, but not quite. Most "solid" foods are like sponges -- a solid framework with liquid trapped in. All fruits, bulbs, and tubers (including tomatoes), contain lots of water -- oftern more than half by weight. Ditto for meat and eggs (including sausages), raw or cooked. And ditto for all Chinese dishes.
There simply cannot be any solid MSG in those foods. Any sodium and glutamate in them will be dissolved in the liquid part, together with potassium, citrate, ascorbate, tratrate, etc.
Moreover, even hard candy will have to be wetted by saliva, and then the gastric juice, in order to be ingested. Even if you put solid MSG directly on your tongue, the taste you feel is not of the solid MSG, but of the glutamate ions dissolved in the saliva.
Except for a few extreme cases like spores, every plant or animal cell is a droplet of water with some substances dissolved in it (the citoplasm), with some thingies floating inside (organelles), enclosed in a two-molecule-thick oil bag (the membrane) that separates it from the liquid outside the cells. So, even if you managed to insert a small crystal of MSG into a cell, it would instantly dissolve into separate sodium and glutamate ions.
But, in spite of their apparent fragility, cells have evolved over three billion years some very effective mechanisms (homeostasis) to keep the composition of the citoplasm suitable for their ends. Thus, if you just dissolve some MSG in the liquid outside a cell, none will enter it "uninvited".
There are some big molecules (molecular pumps) stuck through the membrane that can transfer specific substances in and out, as needed by the cell. But there is no "MSG pump". If a cell needs to take both sodium and glutamate, it will use two separate and independent pumps, one for each ion.
Other such big molecules that sit across the membrane (receptors) can bind to definite chemicals outside the cell, and, when that happens, release other chemicals inside the cell. That is how some cells in the tongue detect glutamate in the saliva, and ultimately cause the brain to feel the "umami" taste. AFAIK there are no receptors in the tongue that detect sodium ions (the "salty" sensation of table salt being due to the chloride ion); but, if there were, they would be separate from the glutamate receptors.
Again, all this is pretty basic high-school chemistry and biology. I really don't know what scientific references I could give on that, if you don't believe the basics, and are unwilling to even read a Wikipedia article.
Anyway. the point is that no one can really ingest MSG, just as no one can ingest table salt. It is always separate ions; and the sodium from MSG is exactly equivalent to the sodium from the table salt (that Chinese dishes and soy sauce have plenty of, too).
When articles talk about health consequences of MSG, it is, first of all, for convenience, just as when oceanographers talk about the salt contents of sea water (where in fact there is no salt). They are really and obviously looking at the effects of glutamate, because it is the special thing that MSG has. Just like when they study the impact of "salt" in the diet, it is actually the effects of excessive sodium intake that they are after -- because any chloride is largely irrelevant once it gets to the stomach, since the gastric juice contains a lot more chloride than there is in food.
Second, researchers say "MSG" because the way they add glutamate to the volunteers' diet, in their studies, is usually by adding MSG to the food. (But, indeed, negative results in such studies cannot conclusively disprove the reality of the "Chinese Restaurant Syndrome", because the latter may not be due to MSG, but to some other chemical that is present in some dishes -- maybe created by reaction of glutamate with some other ingredient, or maybe not related to glutamate at all.)
Third (and I don't know if that is the case in the paper that bothers you), when talking about the glutamate contents of foods that does not come from adding MSG, researchers may still use "MSG" to make it easier for readers to compare their numbers to the food research. That is, "XX contains NN mg/kg of MSG" as way of saying that "one kg of XX contains as much free soluble glutamate ions as NN mg of MSG".
--Jorge Stolfi (talk) 21:33, 24 February 2017 (UTC)
You must provide source stating "There simply cannot be any solid MSG in those foods" Cathry (talk) 22:39, 26 February 2017 (UTC)
I think that I provided enough information already, and apparently you are not willing to check even the wikipedia articles about salts and solutions, cell metabolism, etc.. Sorry, but you came up with the implausible theory, and you claimed that the article or its references are wrong or incomplete; so you owe us a reference that says either (1) there is solid MSG in Chinese dishes, sausages, and other foods, or (2) some (confirmed or alleged) effect of MSG in such foods is not simply the sum of the effects of glutamate and of sodium separately, but specifically of the two being ingested together. --Jorge Stolfi (talk) 06:32, 5 March 2017 (UTC)
I answered early about "possible specific action because of simultaneous large doses of glutamate and sodium", so this is the reason, helth effects must be here. About solubility: you can do simple experiment, put teaspoon of salt in glass with clear water, and find that after half a hour some crystals still there. Cathry (talk) 14:00, 6 March 2017 (UTC)

Health effects are fine here IMO. Doc James (talk · contribs · email) 02:16, 6 March 2017 (UTC)

Misquote of the review article corrected[edit]

The article by Obayashi and Nagamura (2016) was misquoted. Differences were found but they suggested more research. I used their words so that no one could claim was I being biased. — Preceding unsigned comment added by FFN001 (talkcontribs) 14:12, 22 February 2017 (UTC)

Please provide a reason why my edits were changed. Otherwise, I will change it back to the author's words. — Preceding unsigned comment added by FFN001 (talkcontribs) 20:34, 22 February 2017 (UTC)
They weren't misquoted - that's not what a quote is. Misrepresented perhaps? But I think the existing text accurately reflects their findings without putting a massive quote into the text. --tronvillain (talk) 21:39, 22 February 2017 (UTC)
And if one did feel compelled to have a quote, using something from the conclusion of the paper rather than the abstract might be worth a try:

From the fact that the results of the human studies are not consistent and it is assumed that most studies using beverages as a vehicle are not properly blinded, we suggest that a causal relationship between MSG and headache has not been proven. In addition, statistically significant differences in the incidence of headache were not observed when MSG was administered with food, except in one case of the female group where the blind integrity was questionable. It would seem premature to conclude that the MSG present in food causes headache.

I think that could accurately be summarized as as something like "but double-blind tests have found no significant evidence of this", or perhaps even "but there is no good evidence to support this."
One out of six studies did find a significant effect when taken with food and four out of seven found an effect without food. Plus the author calls for more research. Please quote them accurately. — Preceding unsigned comment added by FFN001 (talkcontribs) 00:11, 23 February 2017 (UTC)
It's not Shakespeare but here is my factually accurate paraphrase of the article findings, "A article reviewing research about the link between MSG and headaches explained that only one of six studies showed a significant effect when taken with food (and then only for women), though four of seven studies showed it caused a headache when taken without food." — Preceding unsigned comment added by FFN001 (talkcontribs) 00:18, 23 February 2017 (UTC)
Ref says "we conclude that further studies are required to evaluate whether or not a causal relationship exists between MSG ingestion and headache" This is a fair summary "but double-blind tests have found unclear evidence regarding if this is the case." of that. Doc James (talk · contribs · email) 13:20, 23 February 2017 (UTC)
I quoted from the conclusion above, which says that the studies which found a significant effect were unlikely to have been blinded. The ones that were properly blinded (the ones with food, except one in which "the blind integrity was questionable") found no significant effect. That's accurately described as there being no good evidence to support MSG causing headaches. --tronvillain (talk) 21:23, 23 February 2017 (UTC)
Yes agree. Doc James (talk · contribs · email) 11:38, 24 February 2017 (UTC)
You cannot be serious. Use the facts, please. I understand that this entry is heavily monitored to ensure that no negative information is posted. I know that it has been watched every day multiple times a day for at least a decade--I have tested that multiple times. Just a word of caution: it is one thing to downplay negative information and quite another to actively mislead people about the content of an academic article. Don't go too far. — Preceding unsigned comment added by FFN001 (talkcontribs) 01:28, 7 March 2017 (UTC)
I have again quoted the article. What I have posted is factually correct and pretty much what you want to hear. Therefore, please don't change it to something incorrect. You cannot say there is NO EFFECT. That is NOT how statistics works nor what they found! — Preceding unsigned comment added by FFN001 (talkcontribs) 01:54, 7 March 2017 (UTC)
Again, the conclusion says (see above) the studies which found a significant effect were unlikely to have been blinded, and the ones that were properly blinded (the ones with food, except one in which "the blind integrity was questionable") found no significant effect. That's accurately described as there being no good evidence to support MSG causing headaches - you apparently want to bring up the studies that had a significant effect but not mention that they weren't blinded properly. I think it's pretty clearly who's trying to be misleading here, SPA. --17:27, 7 March 2017 (UTC)
User:FFN001 you will need to get consensus here before a change occurs. Doc James (talk · contribs · email) 18:20, 7 March 2017 (UTC)
What you wrote above is accurate "the conclusion says the studies which found a significant effect were unlikely to have been blinded." The problem is that MGS is like salt or sugar, you can't properly blind it because you can taste it. MSG does cause headaches--the research explicitly states that it does. However, in undetectable doses it does not. That just means you can't give someone a headache by slipping in undetectable amounts of MSG. However, if you eat MSG all day long, guess what--you might end up with a headache. So your statement is factually misleading. Please use the author's words, or at least their intention, if you are going to cite their work. About the consensus, you won't respond to my posts UNLESS I make changes. So I will use your words for my next change. — Preceding unsigned comment added by FFN001 (talkcontribs) 14:08, 13 March 2017 (UTC)
I have written the following: "An article reviewing studies about the connection between MSG and headaches notes that few articles have actually found a significant effect, and those that did were not properly blinded--hence, people knew they had received MSG which could have caused a psychological effect." — Preceding unsigned comment added by FFN001 (talkcontribs) 14:21, 13 March 2017 (UTC)
The article explicitly states no such thing. In fact, what it says is "...we suggest that a causal relationship between MSG and headache has not been proven." Reporting a headache after consuming MSG when not properly blinded is not good evidence of MSG causing headaches, especially when the effect doesn't appear when blinded... which is why the review has the conclusion it does. When a quality source does a review of properly blinded studies (MSG in pill form or with food) and finds a significant effect, then we'll be able to say that there's good evidence of the effect. And sign your comments - just add four tildes (~) at the end. --tronvillain (talk) 14:32, 13 March 2017 (UTC)
It does multiple times. It says, "Among human studies with the MSG administration with food, significant difference of headache incidence was not found at the dose of 1.5 and 3.0 g in capsule, 3.15 g/300 ml beverage, 3.0 g in boiled rice with pork, and 3.0 g/150 ml beef broth. The significant difference was found only in female administered 3.0 g MSG/150 ml (2.0 %) beef bouillon but not in male." So it does among women (who tend to be smaller in body weight). It also says, "Because of the absence of proper blinding, and the inconsistency of the findings, we conclude that further studies are required to evaluate whether or not a causal relationship exists between MSG ingestion and headache." and "It would seem premature to conclude that the MSG present in food causes headache." The key word is "premature." You are making it sound absolute--there is not connection. The authors say no such thing. They say more research is needed.FFN001 (talk) 14:41, 13 March 2017 (UTC)
And before you undo my changes, tell me what is FACTUALLY incorrect about my statement. FFN001 (talk) 14:46, 13 March 2017 (UTC)
It is also worth pointing out that one of the authors has a conflicting interest. "YO is an employee of MSG manufacturer which joins International Glutamate Technical Committee (IGTC). IGTC is an international scientific non-profit organization, dedicated to the support of targeted scientific research on the biochemistry/metabolism, physiology, pharmacology and toxicology of glutamic acid. IGTC finances the publication fee of this manuscript." — Preceding unsigned comment added by FFN001 (talkcontribs) 14:54, 13 March 2017 (UTC)

────────────────────────────────────────────────────────────────────────────────────────────────────No. Nothing in that quote supports the assertion that "MSG does cause headaches--the research explicitly states that it does." You're attempting to draw conclusions and make connections that are not supported by the source, like "So it does among women (who tend to be smaller in body weight)." When the only groups to have a significant effect weren't properly blinded and groups properly blinded don't find a significant effect (as I have pointed out multiple times), that is generously summarized as having no good evidence for the effect. The lack of good evidence for the effect does not mean there is no connection, it simply means that the available evidence doesn't support one. If quality evidence becomes available that does, the statement can be revised to reflect that. --tronvillain (talk) 17:23, 15 March 2017 (UTC)

MSG-associated Health Issues[edit]

This heading "MSG-associated Health Issues" was already summarized by the heading above called "safety"

The prior wording was more concise so restored it. Doc James (talk · contribs · email) 18:08, 13 March 2017 (UTC)

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