Talk:Gliadin

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The sentence "It is around 60% soluble in ethanol" in this article is nonsense. When you try to solve a substance (in this case Gliadin) in a given solvent (like alcohol) everything will solve (given enough time) until a fixed maximum (a saturated solution). Talking about percentage solubility is therefore obviously an error. I asume that the origina source this was quoted from said something like "Gliadin is solvable in 60% ethanol". 60% then refers to the concentration of alcohol, not the solubility of the protein. I'm not absolutely sure though. Does anyone have a source on this? —Preceding unsigned comment added by 81.175.97.19 (talk) 14:38, 18 December 2007 (UTC)

---> no it is not nonsense! It refers to the fraction of gluten that can be dissolved in ethanol! Not every protein is soluble in ethanol! Many are not! "Gliadins" is the term to describe the fraction of wheat protein that can be solved in ethanol. So the 60% probably refers to the the fraction of gliadins in the whole wheat protein — Preceding unsigned comment added by 31.10.130.238 (talk) 21:55, 6 February 2017 (UTC)

Usually that's the maximum solubility in terms of grams of solute per 100g solvent. While expressing that as a percentage is notationally sloppy, the source probably meant that, if you have n*(100g of ethanol), then up to n*(60g of gliadin) will dissolve in it. Josiah Stevenson 15:41, 5 October 2012 (UTC) — Preceding unsigned comment added by Josiahstevenson (talk • contribs)

What/Who is Ryan Hannah?

Similar to opiates

"Giadins are also implicated in promoting appetite [1]." That "reference" is from a CBS News article. That's hardly what I'd call scientific evidence.

M. Edward (Ed) Borasky aka znmeb (talk) 15:23, 3 September 2012 (UTC)

I'm moving this note to talk.

{{Citation needed|reason=Reliable source needed. The claim about opiate, appetite promoting characteristics is from a highly questionable source who basically makes all his money from having this stance. Did not find scientific backup. Seems like a fringe claim.|date=September 2012}}

It sounds ridiculous but I haven't researched it. I personally think that even a fringe view is worth mentioning if it has a following, as long as we include the rebuttal. There must be some news stories about this guy where they interviewed a mainstream scientist for response. It doesn't belong in the introduction, though. --Nbauman (talk) 17:00, 29 September 2012 (UTC)

In terms of research, what about this paper? http://www.ncbi.nlm.nih.gov/pubmed/6099562 Dweekly (talk) 13:40, 1 October 2012 (UTC)

Agreed, this can't just be thrown in on the say-so of one person with a pecuniary interest. However, it not necessarily nonsense either. Concern about gliadin is not new, as with gluten, and has been associated with more problems than obesity. See http://en.wiki.x.io/wiki/Gluten_sensitivity . There must be additional references given or this is speculation. The journal article above seems related but is very old (1984). doug123w (talk) 17:40, 1 October 2012 (UTC)

http://www.ncbi.nlm.nih.gov/pubmed/6099562 is an in vitro study of competitive binding done in slices of rat brain. WP:MEDMOS says we have to use secondary sources like review articles that evaluate primary literature. If you're making clinical claims, you have to use clinical studies.

There are several good reasons for that guideline. One is that an in vitro study in rats is not evidence that it will have clinical effect in humans, clinical effect in rats, or even that you can repeat the results in live, intact rats.

If you're going to make claims for clinical significance, you have to get published review articles in peer-reviewed medical journals. I think the competitive binding is interesting, but isn't important enough now to include under the standards of WP:WEIGHT. --Nbauman (talk) 21:09, 1 October 2012 (UTC)

At the moment, the article itself says that the claim is scientifically suspect, so why the histrionics in the meta tag? many people will see the cbs piece and come here, and they'll see that it says there is not a lot of evidence. why make it appear as if the wiki article is dubious? 68.174.97.122 (talk) 17:51, 6 October 2012 (UTC)

Opiate-like

It appears that there is support for opiate-like behavior of gliadin. A study performed in 1984 by FR Huebner et. al. looked at the binding action of various wheat proteins on the opiate receptors of rats. This study separated out peptides from wheat proteins and tested them for opiate-like activity at competitive binding sites in the rat brain, comparing them with tridium-labeled doses of dihydromorphine. While some peptides showed no activity, those associated with the gliadin fraction of the gluten complex studied demonstrated activity equivalent to 1 nM of morphine in the rat brain, indicating opiate activity. http://www.ncbi.nlm.nih.gov/pubmed/6099562 — Preceding unsigned comment added by 70.197.193.184 (talk) 19:10, 6 October 2012 (UTC)

Basically, you take a protein, break it down into smaller fractions and see how it reacts to stuff. In this, the research focused on how these building blocks attached themselves to opioid receptors. However, that doesn't mean the protein itself will attach to opioid receptors, so citing it as evidence for opiate-like activity of gliadin is nonsense.

The fact that the doctor in the CBS article calls the protein an opiate seriously brings into question his competence or at least his schooling. It's classic paranoid woo. — Preceding unsigned comment added by Stui (talk • contribs) 13:28, 7 October 2012 (UTC)

It is possible that some day, someone will provide data to support Davis' claims, but until then it's unsupported bullshit.

But, you have to do things in Wikipedia style according to Wikipedia guidelines. In Wikipedia you have to deal with bullshit in specific formalized ways. Please read WP:RS carefully. According to WP:SAID, you can't use "claims". You can't say that "virtually no scientific evidence supports this view", even if it's true, even if you're a notable scientist yourself, unless you can find a WP:RS that specifically says that no scientific evidence supports this view. I'm going to change the section to reflect that.

However, under Wikipedia guidelines, you can delete the whole section under WP:WEIGHT. --Nbauman (talk) 15:33, 7 October 2012 (UTC)

It's been a while since I did much editing on here, so I will bow to your knowledge. I would suggest it is deleted unless there some solid evidence in that case. It's the sort of bullshittery that shouldn't be acknowledged until it is more than a mere assertion by some quack.

Stui (talk) 15:58, 7 October 2012 (UTC)

Basically the rule in Wikipedia is that in order to make a medical claim, you need at least several WP:RSs, which should be articles in medical journals, not about cell culture, not about mice, but about humans. The detailed rules are in WP:MEDMOS. A self-published book probably doesn't count. If nobody can come up with articles like that for Davis' theories, you can feel free to delete it from the article. --Nbauman (talk) 08:47, 10 October 2012 (UTC)

Here is an interesting analysis of the topic by a PH candidate [1]. It is very detailed and the most concise analysis I was able to find about this topic. 97.85.168.22 (talk) 19:56, 11 January 2013 (UTC)

As an aid to the reader, your link is to The Daily Lipid: Wheat Belly -- The Toll of Hubris on Human Health on the blog of Chris Masterjohn. A better resource is a published article by St. Catherine University Professor Emerita and Consultant Dr. Julie Jones: Wheat Belly—An Analysis of Selected Statements and Basic Theses from the Book (http://www.aaccnet.org/publications/plexus/cfw/pastissues/2012/OpenDocuments/CFW-57-4-0177.pdf). Besides putting the opioid receptor studies in context (not based on actually studying humans eatin wheat;not unique to wheat) she covers his other claims in detail with copious references - highly recommended for those curious about "Wheat Belly". ★NealMcB★ (talk) 16:59, 2 June 2013 (UTC)

This couldn't possibly be the same lady with links to the wheat industry, can it? http://www.gowiththegrain.org/about/bios/bio-jones.php Ericoides (talk) 09:55, 1 September 2014 (UTC)

As a cursory reader of this article, I find it surprising that the opiate properties of gliadin are not mentioned since they are documented effects on mammalian brains. http://www.ncbi.nlm.nih.gov/pubmed/6099562 Without any evidence to the contrary that these properties are observed in nature, it would appear then that the article on this topic is not a neutral point of view on the available science on this protein found in wheat products. 128.32.166.162 (talk) 21:14, 24 January 2013 (UTC)

As a scientist, I can answer those claims to some degree, although I do not work with gliadin. These tests were very artificial in the sense that they were not done in a living system; instead, the gliadin protein was chopped up by one or two enzymes, then exposed to rat brain tissue in a petri dish. It does not show that this can occur in a living being. In animals, it is highly unlikely that large peptides such as gliadin will be absorbed into the bloodstream and have a long enough half life to cause any such effects. The ability of large peptides to cross into the bloodstream is demonstrated, but is very likely inefficient at best. Second, there is absolutely no guarantee that a protein can cross the blood-brain barrier to elicit effects on the brain. Case in point, the drug Imodium (Loperamide) is actually an opiate, but it is rapidly exported by neural tissue by P-glycoproteins so is unable to act as an opiate in humans. In vivo, there is extremely little chance that such a large peptide could even cross into the brain. It's pseudoscience at its best. Honestly, I think people should stop being so scared of what they eat and just not eat so much of it! If wheat makes up the vast majority of your daily calories, of course it's going to cause problems! --Areun2 (talk) 05:49, 11 October 2013 (UTC)

'Wheat Belly'

"If a topic has received significant coverage in reliable sources that are independent of the subject, it is presumed to satisfy the inclusion criteria for a stand-alone article or stand-alone list."

If you can find several sources using the term that do not stem from William Davis then go ahead and make an article for it and link it in See Other but after the first 5 Google pages of search it is ALL stemming from him. 97.85.168.22 (talk) 19:15, 11 January 2013 (UTC)

Genetic Testing

The entire sentence "(Discovery of?) this protein and subsequent intolerance is a result of genetic testing in the 1960s and 1970s carried out by genetic researchers" is incredibly suspect and misleading. First, the introduction of semi-dwarf wheat by Orville Vogel and Norman Borlaug did not magically create gliadin, as this sentence and its source suggests. Gliadin is a class of proteins referring to the gluten in wheat. Similarly, Hordein refers to those found in barley, and Avenin refers to those found in oats. It is in all ancestral strains. However, "the dominant T-cell responses are to epitopes that cluster within a stable 33mer fragment formed by physiologic digestion of distinct α-gliadins" [2][3]. This article goes on to say that some diploid and tetraploid wheat varieties may lack this epitope, opening up the suggestion that this more immunogenic isoform of gliadin was introduced with hexaploid or even the dwarf wheat strain that is an ancestor of all modern wheat varieties. However, it is entirely disingenuous to suggest that gliadin was absent in ancient wheat varieties. Secondly, the "genetic testing... carried out by genetic researchers" is- while accurate- a very misleading way to phrase the sentence. To most people, this translates to "modern wheat is a genetically engineered monstrosity," whereas they really mean "modern semi-dwarf wheat was produced from traditional breeding by wheat breeders (aka population geneticists)." This is exactly how the author of that source [4] sells his point of view. It pulls at people's fears to make them believe whatever else they have to say. Finally, do we really want an article from CBS news as a source on wikipedia? Lets keep this page and everything else based on peer-reviewed scientific articles please. --Areun2 (talk) 05:29, 11 October 2013 (UTC)

Glisodin

The current section referencing SOD and glisodin has been so heavily modified that it no longer makes sense! Perhaps someone could look at it, and fix it up! Thanks. Jpaulm (talk) 13:31, 17 May 2014 (UTC)

Gliosdin doesn't seem to have reliable evidence behind it. It's literally just a mixture of gliadin + cantaloupe. And I can't find any evidence that the gliadin actually causes SOD to be absorbed via the gut. — Preceding unsigned comment added by 71.232.29.190 (talk) 23:43, 8 February 2020 (UTC)

And there is actually evidence that it DOESN'T allow SOD uptake: https://pubmed.ncbi.nlm.nih.gov/15621710-influence-of-an-orally-effective-sod-on-hyperbaric-oxygen-related-cell-damage/ "Neither SOD and Cat nor GSH and GSSG were significantly affected by this preparation or HBO exposure" — Preceding unsigned comment added by 2601:19B:A00:4750:353E:471F:28B:E434 (talk) 23:54, 8 February 2020 (UTC)

Gluten

The gluten page says "Gluten is the composite of a gliadin and a glutenin" but on here it says "Gliadins and gluten are essential for giving bread the ability to rise properly during baking." But if gluten is made of a gliadian and a glutenin, does that sentence make sense? --maye (talk) 05:19, 23 May 2014 (UTC)

Reference is a dead link

First reference links to http://www.accessscience.com/content.aspx?searchStr=wheat&id=744900, which is a bad URL. 86.173.220.100 (talk) 16:56, 18 September 2016 (UTC)