# Talk:Vitamin B12

I skimmed the article, and higher blood test results did not seem well covered. While I was in the hospital I had a higher than normal level of B-12 a couple years ago in a blood test. 1600pg/ml. 232-1245 is normal range. I see in the previous talk section some of my confusion concerning what I have read. And in the diagnosis section of the article. 
I stopped taking the high-dose (1000 mcg) sublingual weekly tablets I had been taking for years. Fellow paranoid vegetarians will understand why I was taking them to begin with. I was not fully vegetarian then or now. Though I was fully vegetarian at times before that, and that is where the B-12 supplementation was fully engaged. I have no idea if this blood level was a symptom of other health problems, or a cause of health problems, or both. The whole causation/correlation quandary. Anyway, I did as I was told by the doctors, and figured they were covering all the angles they knew about at the time. 
The literature says it could be a symptom of some serious problems that require diagnosis. So that should be better covered in the article. And people should know more about the blood tests. Many people, myself included, had no idea that one could take too much B-12, or have too much in their blood. It's still not clear in a lot of the literature I see. And the previous talk section makes me even more confused.
See: 

https://www.google.com/search?q=too+much+b12+in+blood+test
What cancers cause high B12 levels?
Other studies focusing on specific cancers have shown a strong association between elevated B12 levels and liver cancers (OR 3.3 [95%CI: 1.1–10.4] for hepatocellular carcinomas and OR 4.7 [95%CI: 1.2–17.9] for other liver cancers) [16], a moderate association with prostate cancer (OR 1.1 [95%CI: 1.0–1.2]) [17], and no ...Feb 9, 2020

Strength of the Association of Elevated Vitamin B12 and Solid Cancers

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7073937
Significance of elevated cobalamin (vitamin B12) levels in blood

https://pubmed.ncbi.nlm.nih.gov/14636871
That article lists similar articles after the abstract. 
And I don't see anything in the article about how much better sublingual absorption is versus just swallowing a tablet. I don't know. I would like to know from some authoritative source. I would put the tablet between my gum and teeth, or under my tongue. Or alternate around my mouth until it slowly dissolved. If it is significantly better absorbed, then that could be a problem since one could be more easily getting too much B-12. On the other hand people who can't absorb it in their stomach, need to know what exactly is true, so that they can safely take the correct amount of B-12 if they need supplementation. 
Another thing I didn't see in my skimming of the article: 

https://www.google.com/search?q=3+to+5+years+to+lower+vitamin+b-12+stores
Unlike most other vitamins, B12 is stored in substantial amounts, mainly in the liver, until it is needed by the body. If a person stops consuming the vitamin, the body's stores of this vitamin usually take about 3 to 5 years to exhaust.

Vitamin B12 Deficiency - Disorders of Nutrition - Merck Manuals. 

https://www.merckmanuals.com/home/disorders-of-nutrition/vitamins/vitamin-b12-deficiency
People who eat a vegan diet and do not take vitamin B12 supplements or eat foods fortified with vitamin B12, are also at risk. Stores of vitamin B12 in the body can last around 2 to 5 years without being replenished, so it can take a long time for any problems to develop after a dietary change.

Vitamin B12 or folate deficiency anaemia - Causes - NHS. 

https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/causes
--Timeshifter (talk) 17:35, 14 June 2024 (UTC)

Of the two refs you mention, Ermens et al 2003 PMID 14636871 is already in the article in the Diagnosis section as ref #55. The article text under-plays the potential importance of elevated blood B12 as a cancer marker or other disease marker. The second is Urbanski et al 2020 PMID 37050436, presenting the results of a large clinical trial (case control design) with results as your wrote = increased risk of some cancers.
There is some other literature. Liu et al 2024 PMID 38252787 reviewed the literature and reported that serum vitamin B12 concentration (>600 pmol/L) was associated with increased all-cause mortality. In contrast, Obeid 2022 PMID 36364737 concluded "Therefore, there is not sufficient evidence to assume that high plasma vitamin B12, high B12 intake, or treatment with pharmacological doses of vitamin B12, is causally related to cancer." Andres et al 2013 PMID 23447660 attributed elevated serum B12 to "solid neoplasms, haematological malignancies and liver and kidney diseases. This review reflects the potential importance of the vitamin B12 assay as an early diagnostic marker of these diseases."
I agree that this topic of elevated B12 deserves more content in the article, and to clarify whether high intake elevates serum concentration and disease risk, or if the diseases in question cause the elevated B12.   David notMD (talk) 02:46, 15 June 2024 (UTC)
For those not familiar with PMID numbers, https://pubmed.ncbi.nlm.nih.gov/ is the site for the US Library of Medicine and a search on the PMID number will go to the article abstract. For some, the whole article is also free. David notMD (talk) 13:34, 15 June 2024 (UTC)
Thanks for the comprehensive reply. I guess I will go with this: Obeid 2022 PMID 36364737 concluded "Therefore, there is not sufficient evidence to assume that high plasma vitamin B12, high B12 intake, or treatment with pharmacological doses of vitamin B12, is causally related to cancer."
I am a cancer survivor, and 70 years old, and take a PPI. So I have the conditions for possible malabsorption problems. After reading all the many health problems associated with deficiency, I am more worried about deficiency than taking too much.
So I am taking a 1 mg high-dose B-12 supplement once a month meant to be dissolved in the mouth. Instead of once a week as before. I am not sure there is any better absorption in the mouth, but from what I read, a high dose is good regardless, because only a small percentage is absorbed (whether through the mouth or the stomach). So I figure I am giving myself multiple paths for absorption.
I mention all this because little of what I have discussed is covered well in the article. NIH has this summary page on B12:
https://ods.od.nih.gov/factsheets/VitaminB12-Consumer
"The amount of vitamin B12 in supplements varies widely. Some provide doses of vitamin B12 that are much higher than recommended amounts, such as 500 mcg or 1,000 mcg, but your body absorbs only a small percentage of it. These doses are considered safe."
Most people aren't going to be getting shots of B12. So high-dose supplements will help many of those who aren't getting shots, and are deficient in B12.
--Timeshifter (talk) 13:35, 18 May 2025 (UTC)

I added a dubious tag to the section saying "the efficacy of methylcobalamin administration in treating vitamin B12 deficiency remains uncertain..." as two of the three given references don't seem to support there being significant doubt about MeCbl's efficacy versus other forms of B12, and the third still says it is beneficial. See more detail at Talk:Methylcobalamin#Treat B12 deficiency. Pagw (talk) 22:48, 7 February 2025 (UTC)

Pagw Do you feel comfortable that you can revise Vitamin B12 and Methylcobalamin to what in your opinon the references support? If yes, go ahead. David notMD (talk) 23:06, 7 February 2025 (UTC)
After some discussion was had on the Methylcobalamin page, I edited this part (under the Supplements subsection), trimming quite a bit of the detail that seemed unnecessary. Pagw (talk) 15:50, 8 March 2025 (UTC)

A recent addition to the article by User:Artoria2e5 (restored after a revert by User:Zefr) adds a section about pseudovitamin B12. There is certainly such a compound, listed on pubchem, for example and it may well warrant an article but I don't think it should get more tnan a brief mention or a "See also" in this article which is specifically about vitamin B12. To place the content here looks like an example of a WP:COATRACK. I am willing to assist with drafting an article about pseudovitamin B12, if that can be agreed as the best way forward. Mike Turnbull (talk) 11:30, 14 May 2025 (UTC)

As trimmed in Special:Diff/1290077963, I maintain that the only mention of pseudovitamin B12 needed is that it is a) inactive in humans, b) found in spirulina and other minor food sources, and c) similar in non-function to an antivitamin B12, giving clarity for the difference.
The rest of the content removed is a laborious biochemical discourse unclear for its significance, WP:UNDUE, and noncompliant with WP:NOTTEXTBOOK #6,7. Zefr (talk) 17:11, 14 May 2025 (UTC)
I have now created the article pseudovitamin B12 incorporating much of the material that seemed off-topic here. Later, we can trim this article and link to the new one. Mike Turnbull (talk) 11:24, 15 May 2025 (UTC)
This article now trimmed of all but a brief subsection on pseudo and anti-vitamins. User:Artoria2e5 might like to do a WP:DYK for the new article, which has already been accepted by the new pages patrol. Mike Turnbull (talk) 15:14, 15 May 2025 (UTC)

Under Plants and Algae, The Academy of Nutrition and Dietetics is quoted as a source for plant-based B12 sources are "unreliable". Given the organizations extensively controversial practices of partnering with food-producing multinationals, including generating misleading nutritional information for cash, I don't think it's an appropriate source of information on the topic. I'm not claiming the findings of the study are incorrect, but it doesn't sit right with me that the statement is leaned on so hard in this instance. Any thoughts? --Jjamieallen (talk) 21:05, 11 September 2025 (UTC)

I disagree with your criticisms. Academy of Nutrition and Dietetics are reliable. It is common knowledge that algae-based b12 sources are unreliable or have an unproven b12 status. No dietetic or health organizations would promote algae as a suitable b12 source for humans. Veg Historian (talk) 21:20, 11 September 2025 (UTC)
You've misunderstood my comment quite wildly; again I make no assumptions at all about the B12 content of algae, or the findings of any studies regarding it. My comment is purely about using an unreliable source for a quote. Needless to say the academy of nutrition and dietetics encounters controversy often enough to have a section designated entirely on their Wikipedia page, and it's quite sizeable. Outside controversies, the financial influence of food corporations on its material and research is a matter of fact and can't be ignored.
I would have absolutely no problem with a similarly, or potentially even more damning source replacing the current one, provided it was from a less controversial and biased organization. Jjamieallen (talk) 22:52, 15 September 2025 (UTC)
What evidence do you have that the Academy of Nutrition and Dietetics is an unreliable source? On Wikipedia their review papers have always been considered highly reliable. This is the largest dietetic organization in the world with over 112,000 members including 1000s of qualified dietitians. The source is this review paper that was peer-reviewed [1] and written by several specialists in the field of dietetics. The review paper itself was thoroughly fact-checked and even had it's own review team. You have presented no evidence that this source fails WP:RS. Veg Historian (talk) 00:16, 16 September 2025 (UTC)
I suggest you go and discuss this on the relevant talk page; it's not me you're disagreeing with here, it's whoever authored  AND's page, specifically sections on criticisms, controversies and industry funding and lobbying efforts. You seem very defensive. Do you have any biases or influences you feel you should be declaring when discussing the AND? I do not. Jjamieallen (talk) 18:38, 17 September 2025 (UTC)
All large mainstream organizations dealing with health or nutrition will have funding otherwise they wouldn't exist; this does not mean they are an unreliable source on Wikipedia. Please read WP:RS. The Academy of Nutrition and Dietetics is considered a reliable source and is used on plenty of articles. Just because an organization may have some criticism on its own Wikipedia article does not mean it considered an unreliable source on Wikipedia. If that was the case we wouldn't be citing any article or paper from any organizations on Wikipedia! I have never seen an experienced user request to have it removed and you certainly have not made a valid case so far. As stated the authors of the said review paper are highly regarded in the field of dietetics. The organization is not listed as an unreliable source. If you believe the source and this entire organization is unreliable the burden of proof is on you to demonstrate that with a consensus. The correct avenue for that would be at WP:RSN. Veg Historian (talk) 20:55, 17 September 2025 (UTC)
"All large mainstream organizations dealing with health or nutrition will have funding otherwise they wouldn't exist"
'Funding' is not a unified concept. Funding comes from many different sources. In the case of the AND, that funding is from industry bodies that want to influence public policy in the form of Lobbying... again, you're completely missing the mark here: this is precisely why the AND's page has such a significant section and controversial funding.
I'm not attempting to remove the AND's status as an un unreliable source, I'm talking about this particular application of the AND as a source.
I asked once, and you ignored, so I'll ask again: Do you have any biases or influences you feel you should be declaring when discussing the AND? Jjamieallen (talk) 08:40, 23 September 2025 (UTC)

The molecular weight listed on this page is for cyanocobalamin. While not "wrong" given that this page covers multiple cobalamin species, I think it could be clarified better. 205.175.106.133 (talk) 18:39, 15 October 2025 (UTC)

All the IDs I checked in the infobox, and e.g. the StdInChI, are for cyanocobalamin. Thus there is consistency, which is all we can manage, I think. If you have a suggestion for clarifying the situation that can be implemented, please suggest it. Mike Turnbull (talk) 10:46, 16 October 2025 (UTC)