Talk:Vitamin A/Archive 1

Archive 1

not a disambig page

The disambig template reads:

which this page clearly doesn't do.

I'm not sure why this is a disambig page. Vitamin C, Vitamin D, etc are all full articles. The B vitamins are chemically distinct, so it makes sense to have that page structured as it is. Are the "A vitamins" chemically distinct? I imagine that Retinol and other Retinods are similar. That is, is it even proper to say the "A vitamins"? Does it make sense that a page, like Antioxidant, would link to retinol rather than Vitamin A?

I propose that this page no longer be considered a disambig page. The disambig template should be removed, and the article on Vitamin A, in all forms, should be expanded (or simply allowed to expand).

Perhaps it could be marked a stub? Alternately, it should state that "When people refer to Vitamin A, they usually mean blank..." — baisically turning this short list into a short pargraph. Still, it shouldn't be a disambig page.

Any thoughts?

Disclaimer: IANAN, I am not a nutritionist (but I've seen one on TV). — gogobera (talk) 04:37, 21 December 2006 (UTC)

I was the one who turned this page into a disambig page. Basically I did it because I thought "retinol" was overly specific -- from a nutritional standpoint, you can get vitamin A from plant foods, but you can't get retinol from them, unless someone happens to have smeared them with liver :-). Anyway I kind of agree with you that this isn't the best solution as it stands -- most of the information at retinol really belongs at vitamin A, except for the purely chemical stuff. See talk:Retinol#Vitamin A redirects here; should it? and add your two cents. --Trovatore 04:47, 21 December 2006 (UTC)

I believe that most of the information on the retinol page belongs on this page. In fact the retinol page has more indepth information on vitamin A (especially from a biological perspective) than the vitamin A page. I think it is bizarre that most of the information on the retinol page is not about retinol. I do not have the technical skills to do this, but if someone worked on the organization I could help with the content. Jasonbholden (talk) 00:33, 11 April 2008 (UTC)

Cod liver oil

Why is there a link to this page titled "Vitamin A overdose"? --Connel MacKenzie - wikt 02:11, 1 January 2007 (UTC)[[

There is a 'See also' over at Cod liver oil, with a piped link called 'Vitamin A overdose' pointing to Retinol#Retinoid overdose (toxicity). Seems perfectly correct, so far as I can tell. The link was made before the articles on Retinol and Vitamin A were properly sorted out. It is logical to keep the information in the Retinol article because the overdose limitation doesn't seem to apply to beta-carotene. Though there is no separate upper limit given for the beta-carotene form of Vitamin A in our Hypervitaminosis A article. EdJohnston 19:15, 30 October 2007 (UTC)

I think that's wrong. It implies that beta carotene form leads to overdose. You could guess that that's not so from the equivalences section, but we ought to say it explicitly.WolfKeeper 14:52, 1 November 2007 (UTC)

I added a link to a new research paper, but I'm not sure if it is easy to link to that site...(links to a search)Filik (talk) —Preceding comment was added at 08:23, 11 December 2007 (UTC)

Pharmacological definition of Vitamin A

Perhaps this article could provide at least one link to a scientific paper that expounds the pharmacological definition. As a start, I found this short definition on the web:

"Pharmacology: The term vitamin A is applied to a number of substances with very similar structure and similar activity. The principal and most active substance is all-trans retinol (vitamin A alcohol). Vitamin A activity is assayed biologically and 1 IU equals 1 USP unit which is equal to 0.3 µg of all-trans retinol or 0.6 µg of beta-carotene. One retinol equivalent (RE) is the specific biologic activity of 1 µg of all-trans retinol (3.33 IU) or 6 µg (10 IU) of beta-carotene."

From [1]. EdJohnston 17:55, 13 January 2007 (UTC)

Yet another link, this time for the medical uses of Vitamin A, at mayoclinic.com. [2]. EdJohnston 02:00, 15 January 2007 (UTC)

Question about retinol and bone growth

Is retinol good for bone growth or only the pro-vitamin? I have heard that retinol can actually counteract Vitamin D and thus indirectly decrease bone density? More info about the different forms of Vitamin a and how they are absorbed/used by the human body would be appreciated, from anyone with the knowledge and interest to write it. 70.231.232.183 06:06, 28 August 2007 (UTC)

section needed: Health benefits

A section on Health benefits should be added, similar to B_vitamins#Health_benefits. Ajonlime 19:44, 14 September 2007 (UTC)

Please don't add it, this is just silly. We have information about hypo- and hypervitaminosis. Icek 03:11, 25 October 2007 (UTC)

HIgh vitamin-a foods

I removed apples and beef from the list. Neither seems to be high vitamin A foods; at the very least they were unreferenced.WolfKeeper 02:52, 2 November 2007 (UTC)

Thank you. I double checked this and my sources agree with yours. Antelan ^talk 03:59, 2 November 2007 (UTC)

Vitamin A is also in Avocado BTW

Capitalization?

I capitalized all instances of Vitamin A, instead of vitamin A. It seemed this was capitalized more than uncapitalized. If this is incorrect, please someone make this correction. Fredsmith2 (talk) 18:06, 10 December 2007 (UTC)

I agree that the capitalization should be consistent, but I think the lowercase version is more in line with WP conventions. There probably isn't an explicit MOS statement about vitamins (though it wouldn't shock me if there were; the people who work on the MOS have grabby fingers), but the general rule is that majuscule is used only when it pretty much has to be (proper nouns, quotations, the first word of an article title or section header). --Trovatore (talk) 18:12, 10 December 2007 (UTC)

kk nn —Preceding unsigned comment added by 219.79.160.239 (talk) 15:17, 20 February 2008 (UTC)

Preform vitamin A in foods

Vitamin A in animal foods is primarily in the form of retinyl esters (mostly retinyl palmitate), not retinol. Retinyl esters are hydrolyzed by lipases and retinyl ester hydrolase in the intestine to produce retinol for absorption. I will try to edit the fourth sentence of this article accordingly. 169.237.138.179 (talk) 17:42, 10 April 2008 (UTC) I finished my changes. If there are any errors or you want some references go ahead and make the appropriate changes. I do have texts that I could reference if you think that is necessary. Jasonbholden (talk) 17:57, 10 April 2008 (UTC)

If you have references you certainly should add them. Even if not "necessary" they are certainly helpful. --Ericjs (talk) 13:53, 22 June 2009 (UTC) papayas are an exellent source of fiber

Elena

solja girl tell'em

Scope of the article

The article currently says that vitamin A is only retinoids. However, we have a separate article on retinoids, and additionally, in common usage vitamin A also applies to beta carotene. Further I googled 'vitamin A' and found this link[3] which treats the two together. OTOH [4] talks only about retinoid forms.

I'm thinking we should increase the scope of the article to cover carotenoids as well, perhaps including renaming it, or at least talk more about the range of opinions about what is, and isn't 'vitamin A'.

Comments?- (User) WolfKeeper (Talk) 22:43, 16 April 2008 (UTC)

A brief Google search suggests that the retinoids are the compounds that have vitamin A activity, and the carotenoids are considered precursors of vitamin A. I haven't yet found an article which says that beta-carotene *is* the vitamin. Even the NIH fact sheet that you have cited calls carotene a provitamin. Since vitamin A really has a biological definition (that we don't give) I think the lead of this article as well as retinoids could be improved. That's why the quantity of the vitamin is measured in International Units and not milligrams. Even a web source such as [5] doesn't *quite* give the definition, since it talks about 'Vitamin A activity' but doesn't say what that consists of. This activity is probably the ability of a substance to relieve the symptoms of vitamin A deficiency in animals. More library research is needed. For instance, is it really true that carotene is unable to relieve the deficiency symptoms? EdJohnston (talk) 23:34, 16 April 2008 (UTC)

I agree with WolfKeeper -- one of the established usages of the term "vitamin A" includes beta carotene. This usage, for example, is commonly found on nutrition labels, and I would hazard a guess that it is the usage preferred by nutritionists, whereas the other usage is probably preferred by biochemists. We should strive to be clear, but not to favor one usage over the other. (Not too long ago, for example, vitamin A was a redirect to retinol, but somewhere there was a section on "foods containing vitamin A" that listed spinach, which has no retinol. Each of these choices was defensible on its own, but together they obviously failed to live up to the clarity required of WP.) --Trovatore (talk) 23:47, 16 April 2008 (UTC)

The NIH link offered above doesn't equate carotene and vitamin A. Rather it uses the terms 'preformed vitamin A' and 'provitamin A carotenoid.' I have yet to see reliable sources to show there is a group of specialists (nutritionists?) who consider these two the same thing. Though this article already has some very technical parts, it is missing important things like the discovery of the vitamin and the definition of vitamin A activity. It could also do a better job of explaining the relationship of carotenoids and vitamin A. Maybe it's time for a rewrite. EdJohnston (talk) 02:22, 17 April 2008 (UTC)

Specifically it says: Vitamin A that is found in colorful fruits and vegetables is called provitamin A carotenoid. They can be made into retinol in the body.. The thing is a vitamin is something that the body can use to perform a particular purpose, and both some carotenoids and retinoids can do the same things- they are both 'vitamin A' in that sense.- (User) WolfKeeper (Talk) 06:32, 17 April 2008 (UTC)

New edit regarding 'fat-soluble' appears to be contradictory

Though the fat-solublility is of interest, a recent edit that adds 'fat-soluble' to the lead appears to create a contradition. If Vitamin A is declared up front to be a fat-soluble vitamin, how can a sentence near the end claim that it has a water-soluble form? 'Vitamin A activity' is a biological activity and it seems to be measured by a bioassay. If Vitamin A is defined as whatever has that biological activity, then a wide variety of compounds (not all fat-soluble) ought to be considered to be Vitamin A. So it follows that 'fat-soluble' ought not to be announced as part of the vitamin's definition. It's fine for retinal to be described as fat-soluble, but retinal is not the only molecule that has Vitamin A activity. EdJohnston (talk) 02:24, 24 May 2008 (UTC)

Good point. My mistake. You're probably aware that vitamin A is considered to be fat-soluble by most of the public -- that's why I put it at the top, similar to the way that most of the B vitamins have "water-soluble" in their intro. Water-soluble vitamin A is a recent discovery. Incidentally, do you know much about retinyl palmitate? I think it may also be water-soluble; at the least, its Wikipedia article claims that it cannot be overdosed on. ImpIn | {talk - contribs} 02:36, 24 May 2008 (UTC)

You can overdose on retinyl palmitate. I highly doubt it is water soluble, as you are esterifying a relatively long chain fatty acid to retinol. Jasonbholden (talk) 20:06, 26 June 2008 (UTC)

Dermatology and isotretinoin

The dermatology section for Vitamin A talks more about isotretinoin, than it does about vitamin A.

It claims: "For the treatment of acne, the most effective drug is 13-cis retinoic acid (isotretinoin)." and then goes on to talk about isotretinoin for the rest of the paragraph. I feel this section is misplaced and possibly biased, it also does not have some of the most important information relating vitamin A, like this from the isotretinoin page: "The concurrent use of isotretinoin with tetracycline antibiotics or vitamin A supplementation is not recommended. Concurrent use of isotretinoin with tetracyclines significantly increases the risk of idiopathic intracranial hypertension. Concurrent intake of Vitamin A supplementation increases the risk of vitamin A toxicity.[6]" —Preceding unsigned comment added by 70.187.223.167 (talk) 02:38, 15 June 2008 (UTC)

Chart suggestion for vitamins and minerals.

Chart suggestion for vitamins and minerals.

Having been in business with a herbal department, there appears to be a need for a standardized presentation of vitamins and minerals to provide handy information to the general public.

Suggestion the following graph, if someone with this ability can present it as so.

Recommend a stardaized chart. Top lines, recommended daily allowance.

Then prioritized items that provide the element, together with amount of item in each serving and a percentage of the recommended daily allowance.

Why?

Well say vitamin C. One glass of orange juice. 100%

Vitamin D. One egg, 20. 3%

At the bottom of the chart important co ingredients required, and or negative factors to absorption.

--Caesar J.B. Squitti: Son of Maryann Rosso and Arthur Natale Squitti (talk) 09:43, 18 March 2009 (UTC)

Pointer/suggestion regarding Vit A & D toxicity

I don't know how to do this wikipedia thing, please be gentle. New study published December 2008 in The Journal of Nutrition, titled "9-Cis retinoic acid reduces 1alpha,25-dihydroxycholecalciferol-induced renal calcification by altering vitamin K-dependent gamma-carboxylation of matrix gamma-carboxyglutamic acid protein in A/J male mice."

http://www.ncbi.nlm.nih.gov/pubmed/19022954

Here's a writeup on the study:

http://blog.cholesterol-and-health.com/2009/04/tufts-university-confirms-that-vitamin.html

It looks as though "balanced" consumption of vitamin A and D neutralizes the toxicity of either one? 216.166.58.150 (talk) 21:12, 15 April 2009 (UTC)

Sources of vitamin A: "bracketed values"

The section "Sources of vitamin A" says "bracketed values are retinol equivalences". I assume this means the retinol equivalent of the beta carotene they contain. First of all, there are no bracketed values. Parenthesis are not brackets. If the parenthesized values are what is referred to, then it seems ALL values are parenthesized so I'm not sure what value this note has. Thirdly, I would think the purpose of this note would have been to set off the indirect sources of retinol via beta carotene from direct sources of retinol (or retinyl esters), and if so, this purpose seems to have been disrupted, as surely at least liver contains retinol and its vitamin A values are marked the same as sources which I believe to be beta carotene sources (which would be all plant sources if I'm not misinformed). In any case something seems amiss here, which someone who knows the original intention of this comment, or at least someone with expert knowledge of vitamin A food sources should fix. --Ericjs (talk) 14:03, 22 June 2009 (UTC)

Units

Can we use the same units when we talk about Sources of vitamin A (now μg) and when we talk about Toxicity (now IU). This way the toxicity levels could be imeadiatly compared with the intake. —Preceding unsigned comment added by 130.226.204.10 (talk) 08:55, 7 July 2009 (UTC)

Are tests available for vitamin A levels in individuals?

Recommended levels of intake and toxic levels of intakes are not relevent for individuals whose system is not working correctly. that is true but not enough u become a freya stratton and dont want to become that an ugly blonde —Preceding unsigned comment added by 90.4.49.238 (talk) 18:30, 30 January 2010 (UTC)

bi-polar

The changes made in this edit on 25th October 2008 seem to have gone largely unchanged but, frankly, I've no idea where they came from and, to me, they make no sense. For the meantime I'm leaving it and ff anyone wants to explain to me what was meant by "a bi-polar molecule formed with bi-polar bonds between carbon and hydrogen" that's great. No objections, though, and I'll take it out because I'm fairly sure it makes no sense. Mullet (talk) 21:01, 1 September 2009 (UTC)

Mullet: I very much agree with you! I am new here, but as soon as I figure out how things work,I will remove the sentence "a bi-polar molecule formed with bi-polar bonds between carbon and hydrogen" .The part "bi-polar molecule" is missleading because the chemical term does not apply to such a stucture.If it was ment in a different context that must be specified.The part "bi-polar bonds between carbon and hydrogen" is plain wrong.If somebody else can do it faster than I will be able to,then all the better.Cleanthis (talk) 07:25, 3 September 2009 (UTC)

Picture: An Egg

This is the worst photograph in the entire wikipedia. Why an egg? Were no carrots available? I can provide a photo of a carrot, a liver, and some collard greens engaged in rather interesting behavior. If an egg, why in an eggcup? When was the last time anyone saw an eggcup (egg-cup?), besides those of us that visited this page? Thank you for your kind attention to this matter. —Preceding unsigned comment added by 200.62.106.102 (talk) 05:31, 11 February 2010 (UTC)

Historical naming

Shouldn't the article credit Sir Jack Drummond with naming Vitamin A?203.184.41.226 (talk) 21:31, 14 September 2012 (UTC)

caption is at odds with information in the article

The second paragraph of this article says: "In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to an alcohol (retinol) in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal." The caption under the leading picture in this article says: "The structure of retinol, the most common dietary form of vitamin A". Maybe the caption should be changed to "The structure of retinol" or "The structure of retinol, the alcohol form of retinyl palmitate." --98.70.130.191 (talk) 23:35, 1 July 2010 (UTC)

Anyone have access to "Retinoids as therapeutic agents"

I'm concerned that this recent addition misrepresents the source. Anyone have access to the full article? Even if they are being used, I think it is necessary to indicate why they are being used. --Ronz (talk) 19:19, 10 February 2011 (UTC)

Hypervitaminosis A

It seems a little counterintuitive to give RDI in micrograms and toxic dosages in IU. If someone has the knowledge/references, could they please provide measurements in comparable units, or provide conversions of one to the other if possible.

Also, in the section listing Vitamin A content of foods, no volume of food is given and percentages, although explained below seem silly - it would seem to make more sense to provide the percentage contentent of Vit A (even if ridiculously minute) in the absence of food volume... Some foods seem self explanatory (eg egg, pea) - but others can be variable doses. — Preceding unsigned comment added by 49.2.10.223 (talk) 11:08, 6 November 2011 (UTC)

Vitamin A Deficiency

Hello, as I was reading this sentence struck me as illogical:

Early weaning from breastmilk can also increase the risk of vitamin A deficiency.

Have not infants been fed from breastmilk for the last 4,000+ years of human existence. If breastmilk can lead to Vit. A defiency then all those people would be bad off (possibly becoming blind), but they ended up living and producing up to our generation, so this statement seems contrary to reason. Citation please. --Joshuajohnson555 (talk) 00:29, 5 May 2011 (UTC)

Humans have been around for far longer than 4000 yrs, if you wanna soapbox your religion, go elsewhere. As for the sentence, it says the early stopping or "weaning" off of breastmilk can lead to the defiency, as in stopping leads to it. Read closer from now on. Heiro 00:53, 5 May 2011 (UTC)

Thank you for your correction. I will read closer now. --Joshuajohnson555 (talk) 05:26, 5 May 2011 (UTC)

Wow... talk about clutching at straws... original post said 4000+ years, no mention of religion was made. If you want to troll, go elsewhere. Read closer from now on. — Preceding unsigned comment added by 49.2.10.223 (talk) 11:11, 6 November 2011 (UTC)

Vitamin A's composition in papaya - dispute in information between two wikipedia pages

The percentage of vitamin A in papaya cited on this page is different than cited on the page on papaya: http://en.wikipedia.org/wiki/Papaya#Nutrients.2C_phytochemicals_and_culinary_practices. Which is the correct information?

14.98.183.94 (talk) 07:22, 6 May 2012 (UTC)

3D structure model

The solid model of vit A does not seem to match the chemical structure shown, at the -OH end. The model appears to show -CH3-OH; should be -CH2-OH, as shown on the chem structure. ChemStr (talk) 15:26, 8 August 2013 (UTC)

It looks correct to me. Of the thee hydrogen atoms on the right that might appear to all be on the same carbon, one is actually attached to the oxygen. -- Ed (Edgar181) 18:07, 8 August 2013 (UTC)

Review

doi:10.1210/er.2012-1071 - Endocrine Reviews with emphasis on bone health. JFW | T@lk 15:54, 8 December 2013 (UTC)

Toxicity and smokers, drinkers

I noticed in the "Toxicity" section this sentence which I deleted for being unrelated: "Smokers and chronic alcohol consumers have been observed to have increased risk of mortality due to lung cancer, esophageal cancer, gastrointestinal cancer and colon cancer." — Preceding unsigned comment added by 66.235.64.59 (talk) 03:18, 4 February 2014 (UTC)

I think it's just phrased badly. The ref is behind a paywall but it's about "Alcohol and Retinoids". I suspect it may say something like "smokers and chronic alcohol consumers who also take too much Vitamin A have increased risk ...". Someone who has access to the ref (or wants to pay for it) could do us a service by letting us know whether that's true. If it is, then it may well make sense to have that in the article, though of course the wording needs to be cleaned up. --Trovatore (talk) 03:24, 4 February 2014 (UTC)

Sources and bracketed values

In the Sources section, it states that bracketed values are in RAE. But, all the values in the section are bracketed, including for foods where an RAE would not likely be used (such as animal products since in that case, there is no need for equivalence because it is in identity — no conversion). Did this section originally have unbracketed values and someone later came along and thought "Well, this is inconsistent, lemme fit this," not realizing the parentheses, or lack of, served a purpose? — al-Shimoni (talk) 00:36, 16 July 2015 (UTC)

Citation

Citation 14 seems to be broken... 137.222.114.243 (talk) 19:26, 25 February 2015 (UTC)

Numbering may have changed - what is citation 14 now is a working linkDavid notMD (talk) 22:27, 23 March 2017 (UTC)

Funk

In the history section is it not odd that Casimir Funk is not mentioned at all? Sayerslle (talk) 22:31, 8 June 2014 (UTC)

Not really. His work was on discovery of water soluble vitamines (vitamins).David notMD (talk) 22:29, 23 March 2017 (UTC)

Recommended dietary allowance section renamed...

...to Dietary recommendations because values for European Union now added to section. For this vitamin, US/Canada and EU not very different, but for some of the other vitamins and nutritionally essential minerals there are large differences, especially in setting Tolerable Upper Intake Limits (ULs). Also, in the U.S., it is not illegal to sell a dietary supplement that provides more than the UL. This does not appear to be true for vitamin A, as the high dose products are 3000 micrograms (10,000 IU), which is at but not over the UL, but for vitamin D, many products exceed the UL of 4000 IU. David notMD (talk) 09:35, 4 September 2017 (UTC)

External links modified

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Patently untrue info in introduction

I don't normally edit these articles but "In general, carnivores are poor converters of ionone-containing carotenoids, and pure carnivores such as cats and ferrets lack beta-carotene 15,15'-dioxygenase and cannot convert any carotenoids to retinal (resulting in none of the carotenoids being forms of vitamin A for these species)." is unsourced and completely false.

One of many papers on the rate of conversion by the "lacking" enzyme: Wang, X. D., Tang, G. W., Fox, J. G., Krinsky, N. I. & Russell, R. M. 1991) Enzymatic conversion of β-carotene into beta-apo-carotenals and retinoids by human, monkey, ferret, and rat tissue. Arch. Biochem. Biophys. 285: 8–16.

Gene: BCO1 beta-carotene oxygenase 1 [ Mustela putorius furo (domestic ferret) ] https://www.ncbi.nlm.nih.gov/gene/101673476

Protein: beta-carotene 15,15'-monooxygenase-1, partial [Mustela putorius furo] https://www.ncbi.nlm.nih.gov/protein/ADK26620.1

EDIT: Forgot to add 14C-beta-carotene-derived retinol data that shows that carotenoids are indeed converted Janine D. Lederman, Katrina M. Overton, Nicolle E. Hofmann, Billy J. Moore,, Jesse Thornton, and John W. Erdman, Jr. Ferrets (Mustela putoius furo) Inefficiently Convert β-Carotene to Vitamin A J. Nutr. 1998 128: 2 271-279

— Preceding unsigned comment added by 72.33.0.70 (talk) 20:29, 22 January 2018 (UTC)

Very interesting, and way outside my expertise. Why don't you go ahead and make the necessary edits? If you have questions about how to do it, feel free to ask, or you can ask me on my talk page. --Trovatore (talk) 20:30, 23 January 2018 (UTC)

Seeing in the Dark

Quotes from the article:

"It is for this reason that a deficiency in vitamin A will inhibit the reformation of rhodopsin and lead to one of the first symptoms, night blindness."

"propagating the myth that carrots enable people to see better in the dark."

They can't both be true, given that carrots are a good source of vitamin A. Stub Mandrel (talk) 21:03, 10 August 2018 (UTC)

Stub Mandrel. I'm trying to understand your point on how the article could be improved. Your first point is that night blindness, particularly in malnourished children, results when vitamin A sources are completely absent from the diet (described here). Your second point about the WWII pilots supposedly supplementing their diet with beta-carotene-rich carrots to improve night vision was a made-up story to deflect the truth about a new Air Force technology. In an adequate mixed diet - as pilots likely had in the war and most people in the western world have today - increasing carrot consumption would do little or nothing to "improve" night vision (as opposed to having no night vision if vitamin A sources were absent). PeacePeace: the vitamin A deficiency article on night blindness, here discusses retinyl palmitate as an oral treatment, and this review, sections 2-4, has background on retinyl palmitate. Here is the PubChem review, which indicates manufacturing background. --Zefr (talk) 17:04, 24 February 2019 (UTC)

Article says, "In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol (chemically an alcohol) in the small intestine."

How can that be true? The claim has no footnote, no source. Since retinyl palmitate is reported to be a synthetic alternative to retinyl acetate, how can something that is synthetic be from "animal origin"? (PeacePeace (talk) 21:05, 23 February 2019 (UTC))

I don't see any contradiction here. Any molecule can be synthetic, if you synthesize it. That doesn't mean it can't also occur naturally. --Trovatore (talk) 20:55, 24 February 2019 (UTC)

Subscripted vitamin A's

The new material about vitamin A₁ through A₅ is of potential interest, but I have a couple of concerns.

• Most importantly, how standard are these distinctions? There's a single ref with an impressive-sounding title, but that is not the same as saying that nutritionists and physiologists in general have adopted them. Sources must be given their due weight. This is beyond my expertise; I hope that others can weigh in. A note to one of the relevant Wikiprojects might not be out of line either.
• For the most part, the subscripts are simply dropped into the article and not further explained. That seems to be of limited value as it stands, though it could be the starting point for an exposition that would be helpful.
• Even if the distinctions are fully standard and explained, it still seems to me that it is standard to talk about "vitamin A" in a way that elides the distinctions, and we should probably do that most of the time, with the subcategories broken out only when they're specifically relevant.

As I say, this is not really my field, so hoping to get some discussion from experts. --Trovatore (talk) 18:07, 9 April 2019 (UTC)

The subscripts and supposed different subtypes of vitamin A derive only from PMID 30358857 which introduces unconventional terms from ligand (in vitro) research. This is not universally accepted and is unconstructive. --Zefr (talk) 19:06, 9 April 2019 (UTC)

Terms

Vitamin A term is not correctly used and I try to correct it while others destroy this editing in an incorrect way and block the article.

Strange strategy to prevent correct terming...?? Why?

In this article it must be clarified, that the term vitamin A used here is simply referring to vitamin A1. i am looking for citations and adding all. Its a lot of work.

Normally we must use a page for Vitamin A and then subdividing into Vitamin A1,2, 3,4 and 5, whiel all informatiosn present here must clearly refer to vitamin A1.

In an article from retinol, this vitamin A1 concept is already clearly described and stated.

Its a lot of work, but blocking when doing teh firsts steps is not a friendly strategy.

Please check all the necessary references and then try to help to make it correct and dont block each other.

I am new here and try to help...but I see as a scientist..I have to handel with guys which clearly state: As I say, this is not really my field, so hoping to get some discussion from experts.

I can not edit in one second all these douments and pages in parallel. So, please help and be patient and check references

Thank you — Preceding unsigned comment added by 149.200.17.61 (talk) 19:07, 9 April 2019 (UTC)

---

to the comment: The subscripts and supposed different subtypes of vitamin A derive only from PMID 30358857 which introduces unconventional terms from ligand (in vitro) research. This is not universally accepted and is unconstructive. --Zefr (talk) 19:06, 9 April 2019 (UTC)

-> ej, please check the retinol page...IT is clear and well know information but not well backed up by refenerces. I agree. So , help AND DONT BLOCK THE TRUTH

These terms are not unconventional but simply correct and were used here in wikipedia in a simply incorrect way, while simplified but still incorrect.

The term vitamin A1 is conventional but was never really used here in wikipedia, which does not mean it is OK. Please check the real literature and dont block all when real scientists do it in a correct way, even if if sounds inconventional by you.

— Preceding unsigned comment added by 149.200.17.61 (talk) 19:12, 9 April 2019 (UTC)

(Closing edit request as edit requests are not used when consensus is lacking. You're free to continue discussing the matter here) – Þjarkur (talk) 19:51, 9 April 2019 (UTC)

Subscripting redux

Can there be a discussion with references here? On the topic of A₁ and so on? I am not convinced that the literature cited so far justifies subscripting. I will add, as there has been unwarrented criticism of editors by 149 as not sufficiently steeped in science, that my credentials include a doctorate in nutritional biochemistry from MIT, doctoral thesis on vitamin A David notMD (talk) 20:58, 9 April 2019 (UTC)

Vitamin A1

The term vitamin A is sometimes used for simplicicy for vitamin A1 but this leads to some problems here.

That here a person states that he has a pHD in Nutritional biochemistry and does not know the difference between the terms vitamin A and vitamin A1 is a bit, well a big big, shock.

As I added a review article exactly specifying this vitamin A1, A2 problems was ment as a friendly gesture to add more on this topic. The wikipedia page vitamin A is unfortunately a cocktail of vitamin A and vitamin A1 mixing all well.

Firstly, the peopel who identified vitamin A by its activity (well explained in the article from wikipedia) found first retinol / beta-carotene, while later an other group found an other molecule with similar characteristics being not retinol. The called their derivative vitamin A2 ( i will addcmore here), it has an additional double bound, like shortly written in an article in wikipedia which is linked to "vitamin A2".

So, for longer time vitamin A1 was used in parallel to vitamin A2.

Unfortunately while vitamin A1 was moste stromngly studied the vitamin A2 term was gettinmg in the background and people misused and simplified the vitamin A1 term to vitamin A. Whiel a vitamin A deficiency and other vitamin A related terms concern vitamin A in general.

-> Please check the vitamin D page all is, not perfectly, seperated into the subforms, while vitamin A is a mixture wrongly put together.

This is a well known basic for nutricionists and well listed in basal literature as well as on many pages about food / nutrition and vitamins, EXCEPT wikipedia.

I wanted to change this and optimise this, BUT its a looot of work and unfortunately the whole chapter vitamin A is severely mixed up. So I stared with the introduction, that vitamin A is a summary for Vitamin A1, A2, the non human relevant A3 and A4 and a new postulated A5. Here I must create many things new by scratch, which is a lot of work and results in problems, while all was mixed up.

In addition, the vitamin A chapter must be completely changed and vitamin A1 and vitamin A must be possibly seperated.

When starting an initiative with blocking and setting back the start, does not help.

So, please check the review which exactly describes the vitamin A concept in detail and then all can well be seperated and well set up.

AND please put back the initial sentences about the definition of the term vitamin A, then teh article can be optimised for things which are belonging to vitamin A1 and vitamin A in general.

IF you need references, PLEASE read the listed article...its a lot of work to back up the whole wiki page with references, especially when people who state have no idea and nutritionists with a phd have never heard about the correct terminology and putting hours of work just back on zero.

Try to be happy and helpful, when people try to correct and dewire things here.....Thank you — Preceding unsigned comment added by Wham2019 (talk • contribs) 11:17, 10 April 2019 (UTC)

The only ref you appear to have attempted to add is Ruhl 2018 (PMID 30358857). That is NOT sufficient to support adding subscript numbers to the Vitamin A or Vitamer articles. No editor is allowed to make text changes first - promising references later. Content may be true, but unless it is adequately referenced, it is not allowed in Wikipedia articles. Given article now protected, you will have to create draft content with references here at Talk. Only after consensus reached will other editors move your changes to the article. Lastly, please be civil. All discussions at any Talk are supposed to be about the content of the edits, not the qualifications of the editors. You are persistently insulting other editors (me included). This does not help. David notMD (talk) 12:02, 10 April 2019 (UTC)

Problem...

So, I am not insulting any people but when a person say he made his phD in vitamin A and does not know what vitamin A is it makes me a bit worried if i shoudl spend time here and change something.

As I said multiple times, PLEAEE read the article and then comment.

In teh article all references are inside, BUT then I must alter the whole text of Vitamin A, make a new page just for vitamin A1 and sort all out.

I am sure this is not working peacefully.

So, again...instead of atlking...please set back the chapter explaining what vitamin A is...thenj we can re-set up the whole page.

Unfortunately as I said....alll is mixed up and cosmetic operations are not advisable here.

So i Suggest..that we se up firtsly a new vitamin A page and add firstly an explanation what is vitamin A, explain the subforms.

Secondly, dissect all infos out about vitamin A1 and create a new page , which is not retinol linked.

Then we can start...

Alternatively we keep it as it is and we start still explaining what vitamin A is...with multiple references, which are present in teh added publication and others

And then ferer to my point, like added well before yesterday that all is now simplified using vitamin A / instead of vitamin A1. Other topics like discovery and toxicity mainly refere also to VA1 , whicl some to VA.

THIS must be clearly marked...

I can not start...because then...i spend hours on setting up all...and some people, who state "not my area" are blocking all. I really dont have time to handle and discuss on that way.

So, as I am a newcomer at wiki, but have a higher education in nutrition and vitamin A ..I can help to re-build this in a good style. But it will need severe editing.

Buy the way in my last 25 years of vitamin A research..I never head from any group at MTI working in teh field specifilaccy on Vitamin A...

So....how can we start....without deleing all correct things and h of work again.... — Preceding unsigned comment added by Wham2019 (talk • contribs) 13:14, 10 April 2019 (UTC)

If, by read the article, you mean Ruhl 2018, not sufficient evidence. As an encyclopedia, Wikipedia is a trailing indicator of science, based on significant content and consensus. Ruhl as ref does not cut it. A path to you is to create a new article on vitamin sub-forms and submit that via Articles for Creation. P.S. The MIT Nutrition department was terminated in 1985. P.P.S. I do not accept "destruction dave" as a moniker (your note in an Edit summary at Dehydroretinal). Again, civility helps here. David notMD (talk) 18:10, 10 April 2019 (UTC)

Vitamin A is not equal to Vitamin A1

We must change the whole topic here and that is painful.

1. We must enter in the vitamin A chapter a heading section about ; "what is vitamin A" We refere here JUST to vitamin A1, while vitamin A1 is redirected to retinol, which is also not correct, because retinol is vitamin A1 alcohol.

2. We must and i start doing it adding new pages for vitamin A2,3,4 and 5, while currently they are just re-directed to one vitamer (dihydroretinal for vitamin A2 and vitamin A1 to retinol.

-> I start now doing it and when I have all the chapter of different vitamin A subcathegories it must be dissected into subchapters clearly indicating what we are exaclty talking about

3. The concept of vitamin A1 and 2 come from the times where these derivatives were identified, while later these 1 and 2 were skipped and for simplicity, which IS NOT CORRCT) just skipped.

In any other platforms these things are well organised, but here in wikipedia all is like a mixed stew and now we must seperate the meat from the water and the onions in this stew.

4. As nobody helps and many people just destructs, I must seperate this here step by step — Preceding unsigned comment added by Wham2019 (talk • contribs) 07:16, 11 April 2019 (UTC)

Ghee's RAE number seems incorrect (in the table under the 'Sources' section)

The table in section Sources currently lists Ghee as having 3069 RAEs. According to USDA, Ghee has 4000 IU of Vitamin A per 100 g, and since "1 IU is the biological equivalent of 0.3 μg retinol", and since (AFAIU) most of Vitamin A content of butter is retinol, this is then equivalent to 4000 * 0.3 = 1200 retinol mcg = 1200 RAEs.

If the above calculation is correct, please modify the mentioned table in section Sources in the following way: For the entry "Ghee", in 2nd column, replace "3069" with "1200.

PS Even if you take the USDA reference on "Butter oil, anhydrous" as a nutritional reference of Ghee, the numbers still don't come out right:

• "Butter oil, anhydrous" has 840 mcg of 'Vitamin A, RAE' which in IU should equal 840 / 0.3 = 2800 IU.
• Ghee currently lists Vitamin A at 3069 IU

Footnotes (from all sections) (Extra section to keep footnotes separate from any other section.) — Preceding unsigned comment added by Shsfafjsdpa (talk • contribs) 07:12, 7 June 2019 (UTC)

References

 Not done: According to the page's protection level you should be able to edit the page yourself. If you seem to be unable to, please reopen the request with further details. Highway 89 (talk) 19:32, 9 July 2019 (UTC)

Language issues in first image "Formation of Retinoic Acid"

Please find an English graphic to use in the English article :^) 98.217.29.214 (talk) 02:47, 18 February 2020 (UTC)

It should be straightforward to edit the image in your favorite photo-editing tool, white-out the captions, and substitute new ones. But what should they say? The second and third molecules presumably can remain "retinol" and "retinal", and I expect the fourth one is retinoic acid based on your header (but this needs confirmation). However I don't know what "Retinol-Ester" would be in English.

(I would remove all the parenthetical names using Vitamin A, given that we're distinguishing between Vitamin A and retinol in this article, and I would definitely remove "Vitamin A1", which seems to be contentious.) --Trovatore (talk) 19:32, 18 February 2020 (UTC)

Actually, we should examine whether that image is useful in that position at all. Why are we leading with the biosynthesis of retinoic acid? --Trovatore (talk) 19:34, 18 February 2020 (UTC)

Info box needed

Does it make sense to copy/paste the info box from retinol or create from scratch? What about the info boxes for retinal, retinoic acid, beta-carotene? Either way, outside my past experience. Anyone want to tackle this? David notMD (talk) 11:02, 19 December 2021 (UTC)

Boldly, copied in the Retinol info box. David notMD (talk) 20:04, 21 December 2021 (UTC)

Fortification ref

The fortification reference Total number of nutrients in food vehicles, according to a country’s fortification standard shows a map of all countries with one or more foods fortified. To view the vitamin A data, at Nutrient (lower right) turn off Select all and instead select only Vitamin A. Can then toggle to show mandatory, voluntary, or combined. Top menu bar, Countries, will go to individual countries, to see which foods fortified, and how much, and compliance. David notMD (talk) 13:34, 9 January 2022 (UTC)

AMD section

Concerning this addition, I'll raise the question about whether to detail the AREDS supplement formula, which includes ingredients that are only presumed to be biologically involved in macular function, such as zinc, and the non-vitamin A carotenoids - lutein and zeaxanthin. While the case for beta-carotene vitamin A in visual function is undisputed, the carotenoids - lutein and zeaxanthin - are not known to be in vivo antioxidants and are unlikely to be involved in vision control, as discussed and sourced here, including a Cochrane review which stated "Supplements containing lutein and zeaxanthin are heavily marketed for people with age‐related macular degeneration but our review shows they may have little or no effect on the progression of AMD." Speculating about non-vitamin A carotenoids is offtopic for the article, and introduces an interface between a highly marketed AREDS supplement vs. absence of good evidence for supplement efficacy. Zefr (talk) 16:54, 5 January 2022 (UTC)

Valid challenge. Which would be a better approach: delete entirely, or remove all content mentioning and referencing work with lutein and zeaxanthin? David notMD (talk) 22:21, 5 January 2022 (UTC)

As lutein, zeaxanthin, and zinc are not vitamin A-related, I suggest the latter solution. Zefr (talk) 22:43, 5 January 2022 (UTC)

Revised, leaving only content on disputed role of beta-carotene in AMD. David notMD (talk) 6 January 2022

Thanks, although I find the following sentence is a concern, These compounds contribute to defense against oxidative processes, which also involve antioxidant nutrients vitamins C and E and zinc, where compounds refer to β-carotene, lutein, and zeaxanthin. Whether lutein and zeaxanthin have antioxidant (or any physiological) roles in vision is unknown and not acknowledged by IOM with recommended dietary intakes, i.e., they are also not defined nutrients, and do not contribute to vitamin A synthesis. Why mention them? Further, the source PMC 8348883 is an MDPI journal suspect as possibly predatory. Looking for a better source. Zefr (talk) 18:13, 6 January 2022 (UTC)

I see no good reviews that confirm efficacy of vitamin A (or β-carotene) in treating AMD, and 3 major sources - LPI, Drugs.com, and NIH do not discuss the topic or are inconclusive (NIH concerning the AREDS supplement formula). I recommend not having this section under Research, as there is no definitive research and no certain involvement of vitamin A. Zefr (talk) 18:30, 9 January 2022 (UTC)

Cut from article and parked in my Sandbox. If no better refs found, will discard. David notMD (talk) 18:47, 9 January 2022 (UTC)

Considering GA nomination

Beginning by reviewing all existing references and ordering sections to match order established in vitamin articles previously raised to GA David notMD (talk) 02:37, 18 December 2021 (UTC)

Several/many are to in vitro, animal or individual clinical trials, hence not WP:MEDRS. Will search for appropriate reviews to replace. Some of this will end up in the Research section. David notMD (talk) 15:30, 18 December 2021 (UTC)

The HIV vertical transmission (mother to infant) text and four refs are not being returned to the article in any form. Among the refs, a Cochrane Review (2017) reported no effect on vertical transmission. A WHO Guideline (2011) specifically did not recommend vitamin A supplementation as a means to reduce transmission. David notMD (talk) 00:52, 19 December 2021 (UTC)

Content and refs on male infertility removed, as all of the evidence was animal-based. No clinical trials. David notMD (talk) 02:17, 19 December 2021 (UTC)

Research section created for content that does not rise to standards of WP:MEDRS. I am open to a discussion about deleting all that instead. David notMD (talk) 10:58, 19 December 2021 (UTC)

Safety section replaced but needs more work and probably more refs. David notMD (talk) 03:33, 20 December 2021 (UTC)

Tackling Topical next, which as it stands, is an utter mess. David notMD (talk) 18:46, 23 December 2021 (UTC)

Made these edits as a start, although uses for acne vulgaris and psoriasis might be added, according to this review and this, Table 1. Skin irritation occurs with topical application, so would be useful to state in this section or in Safety. Zefr (talk) 22:40, 23 December 2021 (UTC)

Replaced entire Topical subsection. Needs more adverse effects content (per Zefr's comments), perhaps within Topical subsection rather then the Safety section. Need to see if non-prescription products available other than in US. David notMD (talk) 09:25, 24 December 2021 (UTC)

Dermatology in Metabolic functions overlaps with Topical in Medical uses. Maybe remove the treatment content from Dermatology. David notMD (talk) 10:14, 24 December 2021 (UTC)

Changed Dermatology section name to Skin. All content replaced. Some more work still needed. David notMD (talk) 13:43, 29 December 2021 (UTC)

Added a Cancer subsection to Research. David notMD (talk) 21:12, 29 December 2021 (UTC)

Added a Definition section, which probably needs more work. As sections added, some duplication across the entire article may occur, which will need clean-up before submitting to GA. David notMD (talk) 20:11, 1 January 2022 (UTC)

Replaced Vision subsection and added Fortification subsection. David notMD (talk) 17:10, 7 January 2022 (UTC)

Replaced Immune function subsection. David notMD (talk) 09:45, 17 January 2022 (UTC)

Added Deficiency section David notMD (talk) 22:33, 18 January 2022 (UTC)

Added Absorption, metabolism, excretion section.

I am done adding and revising sections. If anyone wants to add, subtract, fix, please do. I intend to submit to GA on Feb 1. David notMD (talk) 07:20, 21 January 2022 (UTC)

Not a copyright violation

The non-English blog http://www.janaushadhi.org/ has translated portions of the Vitamin A article into Malayalam and posted it to a website promoting a health business in Kerala, India. Same hyperlink has copied content from Wikipedia articles Vitamin E and Vitamin D. I know this because content I wrote for those articles appears verbatim on the blog. For a copyright check on Vitamin A, the site shows up as a very high probability copyright violation. I have asked the owner of the blog to acknowledge content was copied from Wikipedia. David notMD (talk) 15:19, 31 January 2022 (UTC)