Talk:Vitamin B12/GA1

GA Review
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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:

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