Talk:Vitamin B12

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"Plants"

For openers, please stop calling things that are not plants "plant sources". Thanks.

The source you have added is clear that non-animal sources -- along with the artificially fortified foods and supplements that all vegans should be using -- may contribute modestly to the prevention of vitamin B12 deficiency. The source does not say that, gee, if we had better studies and if more people knew about them we would all be able to live happy, healthy lives based on a few algae, fungi and vegetables processed with fungi and bacteria. The source says, "Together with B-vitamin fortified food and supplements, these foods may contribute, though modestly, to prevent vitamin B12 deficiency in individuals consuming vegetarian diets." - SummerPhD^v2.0 13:35, 18 April 2017 (UTC)

Fair enough that 'Plant sources' is changed to 'Plant and mushroom sources'. The cited source speaks of "seaweed" in general, not only one type of seaweed. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3062981/ "seaweeds contain considerable amounts of vitamin B12" "In conclusion, several plant-origin foods including seaweed, soybean-fermented foods, and kimchi, may contribute significantly to good vitamin B12 status". In addition, this citation could be added https://www.ncbi.nlm.nih.gov/pubmed/10794633 "green (Enteromorpha sp.) and purple (Porphyra sp.) lavers (nori) [...] are the most excellent source of vitamin B(12) among edible seaweeds". Lavers, Nori, and Seaweed are often interchangeable terms. Please do not revert multiple unrelated entries due to laziness or frustration in the future. Cyrus Freedman (talk) 15:45, 18 April 2017 (UTC)

Please do not accuse me of laziness or assume I am frustrated. Instead, realize that your changes have been challenged repeatedly and slow down. Taking one issue at a time, explain your edits (or, heck, discuss them ahead of time) and allow a reasonable amount of time for responses.

Let's try this issue first: "Plants". Seaweed is an algae, it is neither a plant nor a "mushroom" (fungus). Fermented vegetables are also not plants, they are the result of fungi and/or bacteria partially digesting plants. Fermented vegetables are "plants" to the same degree that bread and beer are.

What is gained by grouping together foods from various kingdoms and grouping them together under some contrived moniker via inclusion? The sources make it clear that animal-based foods (meats, eggs, dairy, etc.) are the main source of B12 for humans. Everything else falls into three broad categories. For vegans, the primary sources are artificially fortified foods and supplements. Finally, a small number of non-animal based foods may contribute modestly to preventing vitamin B12 deficiency in vegans. - SummerPhD^v2.0 19:09, 18 April 2017 (UTC)

There is a confusion for me around vegan sources. The first paragraph says that there are no vegan sources of B12. Then a bit further down, we talk about fermented food and algae. Isn't there a contradiction here? Brainstudent87 (talk) 21:09, 3 September 2018 (UTC)

Most of the apparent B12 sources mentioned under "Plants and algae" are seriously questioned in "B12 in Plant Foods" here: https://veganhealth.org/vitamin-b12-plant-foods/ I'm not qualified to judge its correctness, but it contains enough references for others to do so. If it is correct, then most of the 'sources' mentioned in this section are dangerously misleading for vegans. J77h (talk) 06:41, 30 December 2019 (UTC)

The way this section is worded is misleading. The test done in the studies on vitamin B12 content in seaweed does not necessarily distinguish between vitamin B12 and psuedovitamin B12 (analogue B12). Algea sources tested for vitamin B12 have been shown to contain large amounts of psuedovitamin B12. This is a health problem as pseudovitamin B12 binds to the same cell transporters as real vitamin B12, thus blocking the uptake of vitamin B12 in the cells. Also the wording on fermented foods reads as if many fermented foods contain B12, the science linked does however state: "The Vitamin B12 contents of soybeans are low or undetectable. However, a fermented soybean-based food called tempe contains a considerable amount of Vitamin B12 (0.7–8.0 μg/100 g) [40]. Bacterial contamination during tempe production may contribute to the increased Vitamin B12 content of tempe [41]. Other fermented soybean products contain minute amounts of Vitamin B12 [42,43]." So the detected vitamin B12 in the tempeh tested in the study is due to a bacterial contamination and not a product of the fermentation.

The wording on the page makes it looks like people can eat many types of seaweed and/or fermented soy products and get enough vitamin B12 in their diet, this is not only factually incorrect, but also a dangerous claim. — Preceding unsigned comment added by 2001:4647:C8E3:0:C5A4:E660:C895:DFA2 (talk) 00:29, 1 November 2018 (UTC)

https://www.b12-vitamin.com/analogs/ — Preceding unsigned comment added by 2001:4647:C8E3:0:64F7:A007:FA69:38C1 (talk) 12:52, 1 November 2018 (UTC)

Cobalamin in plants

Can someone add something about how plants obtain cobalamin? They obviously need it, just as animals do, but they don't eat (or most of them don't). The only thing I have found is this which says that B12 "kann in Spuren auch in Pflanzen, die mit Bakterien in Symbiose leben (z.B. Leguminosen), vorkommen" ("can occur in traces quantity also in plants which live in symbiosis with bacteria (e.g. legumes)"). Eric Kvaalen (talk) 16:10, 21 December 2018 (UTC)

That's basically small traces of cobalamin produced by plants interacting with microbes found and bred in animal dung that basically works to fertilize the plant. Hence, "artificial" cobalamin is usually made by means of "potting soil", which is basically earth mixed with dung to grow plants in. Still, the trace amounts of cobalamin produced that way are:

• a.) very, very small and thus not suitable to fix human dietary cobalamin needs (such as from a vegan diet resulting in cobalamine deficiency), and
• b.) are hardly metabolizable by the human body, unlike cobalamin produced in animal products such as meat, fish, milk, and eggs. It's basically identical to the pseudo-cobalamin found in algae that is not suitable to fix human dietary needs.

b.) basically means that even *IF* "artificial" cobalamin derived from growing plants in dung soil could be produced at amounts similar to the amounts found in animal-derived foods and used for human diet, the human body fed such would still suffer cobalamin deficiency because artificial cobalamine is hardly metabolizable and mostly just excreted rather than exploited to feed the body. --46.93.159.143 (talk) 22:30, 10 September 2019 (UTC)

Vascular plants do not require B₁₂, and they use different enzymes and genetic mechanisms to synthesize DNA without B₁₂. All animal life on earth is dependent on B₁₂ for DNA synthesis and maintenance of nerve tissue which cannot work without B₁₂ (technically all life which has cells which contain mitochondria require B₁₂ for DNA synthesis). Plants which contain B₁₂ obtained it from bacterial sources. See Octoberwoodland (talk) 02:20, 22 September 2019 (UTC)

References

Ready or not for a GA nomination?

Starting review of whether this article can be improved before submitting a Good Article nomination. All help welcome. Ordering of sections will be modeled on the GA vitamins C and folate. David notMD (talk) 09:53, 17 December 2019 (UTC)

Several paragraphs are without references. Existing refs may be suitable, need to be reviewed before being used elsewhere. David notMD (talk) 01:02, 22 December 2019 (UTC)

Intending to submit GA nomination on Jan 2nd. All article improvements before and after that date are welcome. Ideally, article will be stable again (not under constant revision) by the time a reviewer agrees to start the process. David notMD (talk) 22:27, 22 December 2019 (UTC)

Nominated January 3rd. David notMD (talk) 11:05, 3 January 2020 (UTC)

Jan 6: reviewing all refs prior to Good Article review process. David notMD (talk) 12:02, 6 January 2020 (UTC)

Added a Pregnancy and lactation subsection to Deficiency section and added a Society and culture section after History. David notMD (talk) 12:07, 11 January 2020 (UTC)

GA Review

This review is transcluded from Talk:Vitamin B12/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: HaEr48 (talk · contribs) 01:49, 11 April 2020 (UTC)

Will review this. HaEr48 (talk) 01:49, 11 April 2020 (UTC)

This is a decently written article, well-referenced and verifiable for the most part, properly structured, broadly covering major aspects, and no unnecessary detail. No neutrality, copyvio, or WP:OR issue as far as I can tell. Images are appropriately licensed. I think the main challenges are readability for a broad audience ( a common problem for technical articles like this) and partial lack of references in some sections, but I believe nothing that can't be ironed out in review. Here are my more specific suggestions, which I hope would help:

• "The vitamin exists as a family of vitamers defined as a number of chemical compounds having a similar molecular structure, each of which shows vitamin activity in a vitamin-deficient biological system". Suggest starting with "The vitamin is not a single compound, but rather .." For a general reader like me it's not obvious that this is implied by the sentence, I have to click things like vitamer in order to find out. Probably even mention that their difference is due to one single group.
• Similarly in the lead paragraph: "It consists of a class of chemically related compounds (vitamers), all of which show physiological activity". I suggest something like "It is not a single compound but a group of four vitamers, compounds which are chemically related and show similar physiological activity." Also "consists of" can be ambiguous in the sense of "protein consists of amino acids" which I realize is not the case here.
• Any reference for the first paragraph of "Definition"?
• vitamin activity in a vitamin-deficient biological system: Any link for "vitamin activity", or can we explain briefly just what kind of activity we're talking about?
• In deficiency, where the increased risk for vegetarians, consider mentioning how vegetarians are different from the previously mentioned vegans (this is not always obvious for people)
• "B12 is a co-substrate of various cell reactions involved in methylation synthesis of nucleic acid and neurotransmitters. Synthesis of the trimonoamine neurotransmitters can enhance the effects of a traditional antidepressant" Suggest connecting the two sentences with "including" so that the relationship between these two facts are clear (if they're indeed related)
• Is the passage about homocysteine related to the first two sentences of that paragraph? If yes, suggest explaining how they're related. If not, suggest rewording to make it clear that they're not.
• "As during pregnancy, what the nursing mother consumes is more important than her liver tissue stores, as it is recently absorbed vitamin content that more effectively reaches breast milk": Suggest merging with the sentence for pregnancy to avoid near duplication.
• Prolonged exclusive breastfeeding is a strong indicator : "Prolonged" sounds relative, is there a guidance on how long is considered high-risk?
• The "Deficiency" section seems underlinked, given that there's a lot of technical terms there. Can you find out more links that can be added?
• Severe vitamin B12 deficiency is corrected with frequent intramuscular injections of large doses of the vitamin, followed by maintenance doses at longer intervals : How often is "frequent" and "at longer intervals". I know practices will vary, but it would help to know if we're talking about something like every day, every week or every month.
• AI and UL defined the same as in the United States: grammar
• The original deadline to be in compliance: compliance for using 2.4μg, or compliance for including vitamin B12 at all?
• Absorption is promoted by intrinsic factor. Any reason why not "factors" (plural)?
• Link "post-prandial"?
• Can something be linked for "foregut fermenters" , "first-passage feces", "second-passage feces" (or portions of them, or add brief gloss/description if link is not available)
• "Fortified foods" can we add how the fortification is made? From plants, animals, or artificial?
• Consider merging "Fortified foods" and "Supplements" because it seems they're related, and each is not that long
• "The four vitamers of B12 are all deeply red-colored" How does this reconcile with " Pure cyanocobalamin possesses the deep pink color "
• These are converted to the other methylcobalamin form as needed: What does "other" signify here? Isn't there only one methylcobalamin form?
• the human body has the ability (except in rare cases) to convert any form of B12 to an active form: Does this include pseudovitamin-B12?
• Add citations for the specific facts mentioned in vitamers bullet points?
• The biochemistry section contains many specific facts, I think more references are needed.
• "Three types of enzyme:" incomplete sentence?
• "show the most direct and characteristic secondary effects" link "secondary effects" or reword to be easier to understand?
• Suggest clarifying the "enzyme function" section here and there because it is quite hard to follow right now.
• "There is no "gold standard" test for B12 deficiency because as a B12 deficiency occurs…" This and the following passage seems to belong to the deficiency section rather than in biochemistry? (e.g. it is related to deficiency in general as opposed to this specific biochemical function)
• link/explain "reaction type 1" when first mentioned ? Or does it refer to the three types of enzyme mentioned above?
• the X group is -COSCoA: The X group of what?
• may overwhelm the complex R-factor and IGF-factor dependent absorption: Link or add long form of IGF? Or is it a typo for IF?
• Adsorption: The adsorption through intrinsic factor is discussed in detail, can we also explain how diffusion of B12 works?
• The third para of Adsorption needs references.
• methyl-labelled: would a link to isotopic labeling be appropriate here?
• (the French Sanofi-Aventis and three Chinese companies): Any reason why the Chinese companies aren't named while the French one is? Any indication which one(s) are the bigger producers?

I hope my review is useful. Great job on this article. HaEr48 (talk) 23:53, 11 April 2020 (UTC)

Oy. Will get on all this. David notMD (talk) 01:14, 12 April 2020 (UTC)

Started changes. Will copy groups of the above bullets and paste in with explanations of how addressed, in italics. David notMD (talk) 22:16, 12 April 2020 (UTC)

Numbered the bulleted list of comments and so far addressed numbers 13-20 and 30-35. For each, response to the comment is in italics, first word or words in bold so as easier to see. Will continue to address comments in groups. David notMD (talk) 14:22, 13 April 2020 (UTC)

• 1. "The vitamin exists as a family of vitamers defined as a number of chemical compounds having a similar molecular structure, each of which shows vitamin activity in a vitamin-deficient biological system". Suggest starting with "The vitamin is not a single compound, but rather .." For a general reader like me it's not obvious that this is implied by the sentence, I have to click things like vitamer in order to find out. Probably even mention that their difference is due to one single group. Addressed by rewording of first paragraph of Definition section.
• 2. Similarly in the lead paragraph: "It consists of a class of chemically related compounds (vitamers), all of which show physiological activity". I suggest something like "It is not a single compound but a group of four vitamers, compounds which are chemically related and show similar physiological activity." Also "consists of" can be ambiguous in the sense of "protein consists of amino acids" which I realize is not the case here. Second paragraph of lead revised to be more clear about "vitamers" and how the four now-named forms relate to each other.
• 3. Any reference for the first paragraph of "Definition"? References added and wording revised.
• 4. vitamin activity in a vitamin-deficient biological system: Any link for "vitamin activity", or can we explain briefly just what kind of activity we're talking about? Defined by using a sentence and ref from the Biochemistry section.
• 5. In deficiency, where the increased risk for vegetarians, consider mentioning how vegetarians are different from the previously mentioned vegans (this is not always obvious for people). Deficiency section clearer on vegetarian vs. vegan. Also, older people having lower stomach acid had been mentioned in first and third paragraphs, so cleaned up, with a link to achlorhydria added. Created Diagnosis subsection.
• 6. "B12 is a co-substrate of various cell reactions involved in methylation synthesis of nucleic acid and neurotransmitters. Synthesis of the trimonoamine neurotransmitters can enhance the effects of a traditional antidepressant" Suggest connecting the two sentences with "including" so that the relationship between these two facts are clear (if they're indeed related). Resolved instead by deleting both sentences. The references for both were individual clinical trials, hence not WP:MEDRS. In addition, the content (B12 and depression) needs to be a separate subsection.
• 7. Is the passage about homocysteine related to the first two sentences of that paragraph? If yes, suggest explaining how they're related. If not, suggest rewording to make it clear that they're not. Created a diagnosis subsection.

  Thank you, it is clearer now. Just a small comment, the paragraph looks weird starting with just a quoted sentence without explanation: "At present, no ‘gold standard’ test exists for the diagnosis of vitamin B12 deficiency.". Suggest either (1) adding "According to ...", (2) Partially rewording so that only part of the sentence is in quotation marks. HaEr48 (talk) 13:01, 21 April 2020 (UTC) Framed first sentence of Deficiency with "According to..." Also, added the rest of the quoted sentence.

• 8. "As during pregnancy, what the nursing mother consumes is more important than her liver tissue stores, as it is recently absorbed vitamin content that more effectively reaches breast milk": Suggest merging with the sentence for pregnancy to avoid near duplication. Removed the words "As during pregnancy" but left rest of sentence. It is important to have the two separate paragraphs to address pregnancy and breastfeeding, as each are risks to the fetus and infant, respectively.
• 9. Prolonged exclusive breastfeeding is a strong indicator : "Prolonged" sounds relative, is there a guidance on how long is considered high-risk? Replaced with after six months, and added a mention that risk applies to near-exclusive breastfeeding when the foods been fed are not good sources of B12.
• 10. The "Deficiency" section seems underlinked, given that there's a lot of technical terms there. Can you find out more links that can be added? More Wikilinks added and text shortened because there was redundancy about B12 and homocysteine, methionine and neurotransmitters.
• 11. Severe vitamin B12 deficiency is corrected with frequent intramuscular injections of large doses of the vitamin, followed by maintenance doses at longer intervals : How often is "frequent" and "at longer intervals". I know practices will vary, but it would help to know if we're talking about something like every day, every week or every month. Specifics added, along with new ref.
• 13. AI and UL defined the same as in the United States: grammar Fixed
• 14. The original deadline to be in compliance: compliance for using 2.4μg, or compliance for including vitamin B12 at all? Fixed
• 15. Absorption is promoted by intrinsic factor. Any reason why not "factors" (plural)? No change. From Intrinsic factor, singular applies.
• 16. Link "post-prandial"? Done
• 17. Can something be linked for "foregut fermenters" , "first-passage feces", "second-passage feces" (or portions of them, or add brief gloss/description if link is not available). Better explanation of how foregut and hindgut fermenters getting B12 from bacterial fermentation of plant food; the digestive system bacteria are making the vitamin.
• 18. "Fortified foods" can we add how the fortification is made? From plants, animals, or artificial? Sentence added to state that it is microbial fermentation cyanocobalamin

  Thank you. Add source for the new sentence? HaEr48 (talk) 13:01, 21 April 2020 (UTC) Sentence improved and ref added.

• 19. Consider merging "Fortified foods" and "Supplements" because it seems they're related, and each is not that long. Prefer not. Fortification uses cyanocobalamin, but supplementation offers other vitamers. Also, fortification limited to range of natural foods, whereas supplementation can and often extends to mega-dosing, i.e., amounts in great excess compared to recommended intakes. Added mention and ref that some countries require fortification.
• 20. "The four vitamers of B12 are all deeply red-colored" How does this reconcile with " Pure cyanocobalamin possesses the deep pink color " Removed sentence mentioning deep pink.
• 21. These are converted to the other methylcobalamin form as needed: What does "other" signify here? Isn't there only one methylcobalamin form? Removed "other".
• 22. the human body has the ability (except in rare cases) to convert any form of B12 to an active form: Does this include pseudovitamin-B12? Deleted/replaced "any form" to exclude thinking that pseudovitamin B12 was included. Another editor added content about assay methods for pseudovitamin B12.
• 23. Add citations for the specific facts mentioned in vitamers bullet points? Rewritten and references added.

  " Under normal conditions, oral consumption of any of the vitamers disassociates to cobalamin, and then combined with a methyl ligand in the cytosol or an adenosyl ligand in mitochondria" Suggest adding that these results in the two active forms (MeB12 and adoB12), because it is not necessarily obvious to the general reader. HaEr48 (talk) 13:01, 21 April 2020 (UTC) Agreed, and done.

• 24. The biochemistry section contains many specific facts, I think more references are needed.
• 25. "Three types of enzyme:" incomplete sentence? Converted to a complete sentence
• 26. "show the most direct and characteristic secondary effects" link "secondary effects" or reword to be easier to understand? Deleted Enzyme Function subsection because it was unreferenced garbage.
• 27. Suggest clarifying the "enzyme function" section here and there because it is quite hard to follow right now. Deleted Enzyme Function subsection because it was unreferenced garbage.
• 28. "There is no "gold standard" test for B12 deficiency because as a B12 deficiency occurs…" This and the following passage seems to belong to the deficiency section rather than in biochemistry? (e.g. it is related to deficiency in general as opposed to this specific biochemical function) Moved to a Diagnosis subsection under Deficiency.
• 29. link/explain "reaction type 1" when first mentioned ? Or does it refer to the three types of enzyme mentioned above?
• 30. the X group is -COSCoA: The X group of what? Revised first sentence of the explanation of what Methylmalonyl Coenzyme A mutase does, added ref from that article

  Thanks. Can you add reference also to the last sentence of the Methylmalonyl Coenzyme A mutase bullet point? HaEr48 (talk) 13:01, 21 April 2020 (UTC) Ref added.

• 31. may overwhelm the complex R-factor and IGF-factor dependent absorption: Link or add long form of IGF? Or is it a typo for IF? "IGF" was a typo. The sentence reworded to "The passive diffusion process of B₁₂ absorption may overwhelm the R-protein and IF mediated absorption when oral doses..."
• 32. Absorption: The absorption through intrinsic factor is discussed in detail, can we also explain how diffusion of B12 works? Described as "passive." First and last paragraphs modified to state that passive is a small portion of total absorption of B12 from foods, but becomes a large portion of total with mega-dosing.

  I added "by which most food consumption of the vitamin is adsorbed" to the first sentence that describe the first process, so that it's clear from the get go. See what you think and correct me if I'm wrong Yes, I agree that is an improvement.

• 33. The third para of Absorption needs references. Existing ref and new ref for third paragraph
• 34. methyl-labelled: would a link to isotopic labeling be appropriate here? Addressed by another editor.
• 35. (the French Sanofi-Aventis and three Chinese companies): Any reason why the Chinese companies aren't named while the French one is? Any indication which one(s) are the bigger producers? Chose to delete name of French company rather than add names of three Chinese companies listed in the reference, mostly because this is old (2008) information. Also removed the corporate mention of Aventis and Sanofi in the preceding paragraph.

Will continue to address in groups. David notMD (talk) 14:22, 13 April 2020 (UTC)

*34 made the suggested link and added ¹³C to indicate type of label used. Michael D. Turnbull (talk) 13:27, 14 April 2020 (UTC)

Addressed 8-11 and 21,22. There is no #12; that was a misnumbering when I copied and numbered the list. Still to do: 1-7, 23-29. David notMD (talk) 13:37, 15 April 2020 (UTC)

Addressed 5-7 (leaves 1-4, 23-29). With the establishment of a Diagnosis subsection, content Biochemistry moved to Diagnosis and references added. David notMD (talk) 11:09, 16 April 2020 (UTC)

Addressed 1-4 (leaves 23-29) David notMD (talk) 13:59, 18 April 2020 (UTC)

Addressed 23-25, 28. Leaves 26 and 27. On close read, the entire Enzyme Function section is a farce. Copying it to my sandbox to fix, then will past back in, That will address 26 & 27. David notMD (talk) 00:08, 21 April 2020 (UTC)

@David notMD: Thank you. Your changes look good in general, though I added some small follow up comments above, please take a look. Also, I realized I made a lot of comments, please don't take this to mean that I don't like the article (it's actually the opposite), it's just I believe these will improve the article further. Let me know once you pasted in your update and what you think of my follow up comments above. HaEr48 (talk) 13:01, 21 April 2020 (UTC)

Whatever does not kill this GA review makes it stronger. I deleted the Enzyme Function subsection because it was unreferenced garbage. If there is anything worth salvaging I will revise, reference, and add to Medical uses. Carrying on. David notMD (talk) 21:02, 21 April 2020 (UTC)

I believe I had addressed all of the initial and to-date follow-up comments. David notMD (talk) 10:37, 23 April 2020 (UTC)

@David notMD: Thank you so much for your updates. I think those address my feedback about clarity and referencing. I am happy to pass this article as GA. Keep up your great work! HaEr48 (talk) 12:26, 23 April 2020 (UTC)

Vegan advocacy groups

Pretty sure that ideological groups fail WP:MEDRS. Medical and governing bodies do discuss vegan nutrition and they should be cited instead. Harizotoh9 (talk) 08:23, 20 April 2020 (UTC)

The fact that vegan advocacy groups (no longer named in text of article) recommend fortified foods is not controversial, and in my opinion is information worth referencing. I will, however, find and add government and/or NGO references to the statement. David notMD (talk) 14:59, 20 April 2020 (UTC)

The issue is that vegan advocacy groups fail WP:MEDRS. Thus they can't be used as sources and anything they recommend is irrelevant. The section on fortified foods shouldn't even open with vegans since the vast majority of people who consume fortified foods are omnivores of the general public. Harizotoh9 (talk) 08:06, 21 April 2020 (UTC)

The vast majority of people who consume fortified foods are not selecting those foods because of the B12 content. For cereals, its vitamins. For non-dairy 'milk,' vitamin D. People who choose a veganism diet are exactly the people who are instructed to get B12 from fortified foods or dietary supplements. For this reason, I consider B12 guidance from vegan advocacy groups valid. Citing that information does not bleed over into supporting why people choose a vegan diet, or any other platform of those advocacy groups. This article is in the middle of a Goo Article review. I suggest you bring this discussion to the attention of the reviewer, as we do not have enough participants at the moment to reach a consensus. David notMD (talk) 08:33, 21 April 2020 (UTC)

My position is that WP:MEDRS applies to science evidence. David notMD (talk) 01:08, 23 April 2020 (UTC)

Added Gastric bypass surgery section

Gastric bypass surgery, specifically the Roux-en-Y bypass procedure, is a known cause of B12 deficiency which can be prevented by injection or high dose oral. David notMD (talk) 07:19, 21 April 2020 (UTC)

@David notMD: Should it be under "Deficiency" ? Similar to how pregnancy is under that subsection. HaEr48 (talk) 12:57, 21 April 2020 (UTC)

I agree. Moved it. David notMD (talk) 13:15, 21 April 2020 (UTC)

Did you know nomination

The following is an archived discussion of the DYK nomination of the article below. Please do not modify this page. Subsequent comments should be made on the appropriate discussion page (such as this nomination's talk page, the article's talk page or Wikipedia talk:Did you know), unless there is consensus to re-open the discussion at this page. No further edits should be made to this page.

The result was: promoted by The Squirrel Conspiracy (talk) 02:23, 13 May 2020 (UTC)

(

• Comment or view
• Article history

)

• ... that five people received Nobel Prizes for direct and indirect studies of vitamin B12? Source: "Five Nobel Prizes have been awarded for direct and indirect studies of vitamin B12: George Whipple, George Minot and William Murphy (1934), Alexander R. Todd (1957), and Dorothy Hodgkin (1964). ref #112 The Nobel Prize and the discovery of vitamins(

• Reviewed: Alexandrea Owens

Improved to Good Article status by David notMD (talk). Self-nominated at 01:42, 24 April 2020 (UTC).

General: Article is new enough and long enough
New enough: Long enough:

Policy: Article is sourced, neutral, and free of copyright problems
Adequate sourcing: Neutral: Free of copyright violations, plagiarism, and close paraphrasing:

Hook: Hook has been verified by provided inline citation
Cited: Interesting:

QPQ: Done.

Overall: epicgenius (talk) 13:29, 25 April 2020 (UTC)

Human small intestine?

Text and a ref (Albert 1980) https://www.cmcwtrl.in/publications/4-1980-Nature.pdf were added as claim that bacterial presence in small intestine of humans may result in absorbed B12. Is this strong enough evidence? David notMD (talk) 11:17, 24 August 2020 (UTC)

In addition to this being a primary source, the assumption we would need to make to accept this as written is a problem.

The article discusses possible differences in a localized population, theorizing that differences in gut microflora may be at work. This is in 1980. 40 years later, contrary to all other sources we have, an editor on Wikipedia essentially is telling us that all of the literature published since is wrong. - SummerPhD^v2.0 18:02, 24 August 2020 (UTC)

I agree with you. I just did not want to be hasty. Furthermore article PMID 15539065 states in its abstract that small intestine bacterial overgrowth would, if anything, reduce absorption of dietary B12 rather than serve as an absorbable source of bacteria-synthesized B12. David notMD (talk) 19:22, 24 August 2020 (UTC)

Sentence and Albert 1980 ref deleted. David notMD (talk) 02:49, 25 August 2020 (UTC)

No need to wait on this one. We can find any number of studies that found a swallow in San Juan Capistrano in early February. Nevertheless you were right to question and ax this one. - SummerPhD^v2.0 03:07, 25 August 2020 (UTC)

I took a look at the citations for the Nature article via Google Scholar. There are 185 of them. Of the ones I looked at, they seemed to be interpreting the article to say that the B12 produced by the gut microbiota is unlikely to be available directly to the host (it goes out in the faeces) or if available, still makes only a small contribution so that in vegetarians, for example, it can't prevent B12 stores becoming depleted. Hence I think that here on WP we are justified in ignoring it as being of only minor relevance. Michael D. Turnbull (talk) 11:43, 25 August 2020 (UTC)

´See also´s ´been removed

These notes with links to ´See also´ just have been removed. Without notification.

• Spirulina (dietary supplement), natural (nature) product of algas, including B12
  
• Mineral (nutrient)
  
• Vitamin deficiency
  
• Micronutrient deficiency
  

In my opinion those themes are very direct related to Vitamin B12. I had to do hard works, to just find it for my current needs.
To save time for other researchers and being looking for and finding it fast, it would be very helpful, at least at ´See also´.
But if wikipedia does not have this in mind or at all in interesst, then wiipedia for me is very, very wrong and not to use anymore, for most of nothing. Sorry. This is not to work with.
Further links:

• Human nutrition
  
• Micronutrient
  

--Visionhelp (talk) 04:27, 9 April 2021 (UTC)

My opinions: Spirulina is not a valid 'See also' for vitamin B12 because at that article it clearly states that spirulina is not a source of B12. A see also to Mineral (nutrient) does not apply because B12 is a vitamin. 'See also' for Micronutrient, Micronutrient deficiency and Human nutrition are not useful because no information is present there that compliments the B12 article. The first two are actually Start-class articles that have no mention of B12. David notMD (talk) 22:30, 9 April 2021 (UTC)