Talk:Vitamin B12 deficiency

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Natural Food Sources of B-12[edit]

What's a mollack? Is this some weird spelling of mollusc?--ML5 (talk) 21:25, 18 August 2008 (UTC)

I have done some heavy editing to this section of the article, yet much good work remains to be done here and I would appreciate the assistance of other editors. I have placed citation requests in areas that perhaps most need them because the claims and suggestions are controversial and, to my existing knowledge, unsubstantiated: namely, that bee pollen, kombucha tea, and water kefir grains are "Natural Food Sources of B12" (the title of this section). To me, much of the vagueness and misinformation that existed prior to my edit seemed motivated by a pro-vegan bias that is not based on nutritional and medical evidence , including the suggestion that bioavailable forms of B12 can be obtained from the consumption of plants. Ideally we can work together to get this section in good enough shape that it can be added to the article Vitamin B12. This is a vitally important topic in human health, and should be presented consistently throughout the encyclopedia.Ctconnolly (talk) 10:21, 15 December 2011 (UTC)

I have removed the statements posted by others in the section of the article titled "Natural Food Sources of B12" regarding bee pollen, kombucha tea, and water kefir grains that were in need of citations that I could not locate independently elsewhere, yet I remain open to being presented with documentation supportive of their claims. Please review the recent edit history of the article for details. Thank you.Ctconnolly (talk) 14:56, 15 December 2011 (UTC)

Symptoms under 'presentation'[edit]

The whole section on additional symptoms is uncited - I've deleted the most egregious junk sentences, but I'm strongly tempted to blast the whole thing. Objections? (talk) 06:26, 8 December 2008 (UTC)

In addition to the above, I think that the presentation section needs a reorganization, some additional sub-categories, etc. justin.kirkham (talk) 01:20, 21 April 2010 (UTC)

Inconsistent units of measure[edit]

The units for B12 levels are stated as pg/l in some places and as pg/ml in others, but the similar magnitude of the numbers makes it clear one or the other is incorrect. Which should it be? Reading elsewhere on the web makes me think pg/ml is correct. -- Dougher (talk) 04:55, 29 September 2009 (UTC)

I noticed the incorrect units also. Since they're wrong by a factor of 1000, it is not inconceivable that someone, doing some calculation of appropriate serum B12 levels and the consequent required supplement intake, could kill themselves - either by overdose or deprivation (haven't thought that through)!! Someone should fix this quick! (Not familiar with the process). The units should clearly be pg/ml, as can be easily confirmed from the conversion from pmol/L and the molecular weight, but also from other reference sources. —Preceding unsigned comment added by (talk) 02:27, 25 October 2009 (UTC)

B12 vs. B12[edit]

Any opposition to my changing 35 instances of B12 to B12 for consistency? –davewho2 (talk) 21:00, 20 February 2010 (UTC)

No, but be aware that somebody already went the other way and changed more than a hundred B12's to B12 in the vitamin B12 article, for consistancy. Personally I don't like the subscript much because it's more work and messes up line spacing in some readers. But B12, and even B-12 (which is my preferred reading version) seems to bother other people no end. I don't think you'll find an answer that pleases everyone. All we agree on is that it should be the same thoughout any single article (even if it varies between them). SBHarris 22:25, 20 February 2010 (UTC)
I've changed all body instances of B12 to B12. Thanks for your comment and I hope this is a beneficial change.–davewho2 (talk) 03:26, 22 February 2010 (UTC)

Article is/was a mess, and symptoms have a list of totally nonspecific nonsense[edit]

This article is a mess, with the "lede" consisting of a list of diseases associated with low B12 (but with no proof), and the "symptom" section crowded with nonsense like B12 deficiency causing spots of de-pigmented skin. None of this was referenced, and I've removed it.

A new lede is needed, and I've moved some material over from vitamin B12. I'll work on something that eventually sumarizes THIS article a bit better, but meanwhile, the structure of this article is at least in approximately the correct form. SBHarris 07:31, 17 November 2010 (UTC)


anyone know what happens with traetment? can you recover from myelin damage, or subacute spinal whatcha macallit? I think myelin damage, that's like MS, right? you can repair it? but seriously, can someone knowledgeable add a prognosis section? thx

soil as a food??[edit]

"Before the mass commercialization of agriculture, when we were all pulling vegetables from our gardens and the water wasn't purified with chemicals, the bacteria that synthesized B12 was available to us through the soil and the water; a vegan diet can produce a deficiency unless one uses supplements or eats enriched food but is not caused by the diet itself but by the hypersanitization of our modern world.[22][23]"

This is absurd. It is not supported by the first reference and I can not access the second reference (a book). Eating soil does not provide any more than trace amounts of B12 and the idea that until recently we ate our food dirty or is stupid. Communities that do, do so because they have no choice, they die in substantial numbers as a result, and they certainly have very high occurrence of b12 deficiency. Washing soil off food is a pretty good strategy to live longer and has been a common human practice for millenia. A simple google search reveals these staunchly pro-vegetarian sites debunking the idea that you can eat dirt as an alternative source of b12. You would be better off eating feces. That might give you enough b12 to stave of deficiency if you can manage it. (talk) 05:31, 14 October 2011 (UTC) (talk) 16:25, 13 December 2011 (UTC) The fact that many animals eat their feces upon investigation showed that B12 was excreted in the lower intestine without being absorbed, hence the animal obtained the B12 by eating their feces.

Questionable source: Reference #2, B12 article by "The George Mateljan Foundation for the World's Healthiest Foods"[edit]

I am removing the sentence in paragraph two of the article stating that "B12 is first made by yeasts and microorganisms." Firstly, yeasts are microogranisms. Secondly, to my knowledge B12 is biosynthesized exclusively by bacteria. The reference article also claims that "the exclusive source of this vitamin appears to be tiny microorganisms like bacteria, yeasts, molds, and algae.". Again to my knowledge the only organisms of any kind that can synthesize, thus create, B12 are bacteria. The article has several other misinformed statements, such as:

  • --"More often than not, pernicious anemia isn't caused by a lack of B12 itself, but by a lack of intrinsic factor -- the stomach-made protein required for the absorption of B12." To my understanding the only cause of pernicious anemia is a lack of intrinsic factor. It is this very lack that defines the disease, and distinguishes it from other causes of B12 deficiency.

and consider this quote:

  • --"The ability of a strict vegetarian diet to supply adequate amounts of B12 remains controversial" By "strict vegetarian" it appears to me they are referring to vegan as they make no mention of dairy-product consumption in this context and later go on to say "For strict vegetarians who eat no animal products whatsoever". The vegan diet cannot supply adequate amounts of B12 to a human being without some form of supplemental B12 synthesized by bacteria then placed by man into B12-fortified foods or B12 dietary supplements. This is a well-established fact, supported by major vegan advocacy and research organizations such as the Vegan Society.

and this quote:

  • --"root-level microorganisms (bacteria, yeasts, molds, and fungi) which make the vitamin". Again, to m knowledge the only substances that can biosynthesize, thus create, vitamin B12 are bacteria.

and this quote

  • --"In general, tofus, tempehs, and sea vegetables tend to be more consistent sources of B12 than misos, tamaris, and shoyus." To my knowledge, none of these products are consistent sources of bioavailable B12 for human beings. Leading researchers in vegan nutrition are in agreement with me.

and this quote

  • --"Depending upon the medium in which they are grown, brewer's and nutritional yeast can also be significant sources of B12 in a strict vegetarian diet." Yet my understanding is that these yeasts will only contain B12 if they have been supplemented with B12 that has been synthesized by bacteria. It is my understanding that not all commercially sold versions of these yeasts have been supplemented with B12.

and this quote:

  • --"On a drop-for-drop basis, sublingual (under-the-tongue) forms of B12 deliver more of the vitamin into your bloodstream than tablet or intranasal (inhaled through the nose) versions." What is "a drop-for-drop basis" as a scientific standard? The standard comparative tool in B12 research is milligrams or micrograms, not drops. Many sublingual B12 products are tablets, not drops. Other studies listed in this article state no advantage to sublingual versus consumed pill (see the "Treatment" section of this article for more on this). The Mateljan Foundation's article does have one reference in their list that may provide more details on this subject, yet there is no link to it online, and it is not specifically footnoted to this passage. There are no footnotes within the text of the Mateljan article.

and, finally, this quote:

  • --"Within the plant world, sea plants (like kelp), algaes (like blue-green algae), yeasts (like brewer's yeast), and fermented plant foods (like tempeh, miso, or tofu) are the most commonly consumed food sources of vitamin B12, although none of these plant foods can be counted on to be a consistently excellent or very good source of the vitamin." To my knowledge, none of these can be counted on as a bioavailable form of B12 for human beings at all, unless they have been fortified by man with B12 from bacteria.

For these reasons, I am removing this reference from the article as well as the passage in paragraph two of the article that references it. I would welcome the opinions and scientific evidence of other editors. Thank you.Ctconnolly (talk) 08:07, 17 December 2011 (UTC)

COMMENT The sublingual B12 thing continues almost like a religion. Some idiots decided that since nitroglycerine must be given sublinqually (to bypass liver metabolism) that this route should work for other things, too. But B12 is SUPPOSED to go to the liver, and there is NO good evidence that more B12 gets into you if you suck on a sublingual pill than simply swallow one (or even better chew it). The one study best study I know of, found no difference between B12 levels in pills vs. sublingual, but found very slight (statistically but not clinical relevent) differences in homocysteine and MMA levels. Since it hasn't been replicated, I don't think we know anything here strongly enough to put in an encyclopedia article.

I agree with the other stuff you say, save that that blue green algae isn't an alga but a (badly named) type of cyanobacteria, and in theory might produce normal B12, like other bacteria. Here's a (poorly controlled) study of Klamath cyanobacteria in humans: PMID 20108213, which includes decreasing homocysteine. However, here's another source PMID 17959839 that claims that most cyanobacteria produce pseudo-B12. This would raise blood B12 levels on assay, but should have no affect on homocysteine. So this question is still open, at least to me. The Klamath people naturally will want their product to have real B-12. SBHarris 19:46, 17 December 2011 (UTC)

COMMENT Thank you Sbharris for the formatting changes to my initial post and for the information on sublingual research and blue green algae. I've also made recent edits to the section of this article now titled "Dietary sources of B12". I did not title it "Food sources..." because the discussion was getting down to the level of bacteria and the B12 supplementation of foods. Earlier versions of this section of the article (then under the title "Natural food sources of B12") seemed to me to contain information consistent with the above-mentioned claims of the Mateljan Foundation that are sharply contested by leading researchers in vegan nutrition such as the Vegan Society and the authors of the books Becoming Vegan and Plant Based Nutrition and Health. Any comments you would have about the scientific accuracy and the general style of presentation of this section of the article would be appreciated. Only if time and energy permits of course. Thank you again for the information you've already shared that can further improve this article.Ctconnolly (talk) 21:44, 17 December 2011 (UTC)
"COMMENT" Cyanocobalomin is too large a molecule to appreciably absorb sublingually. |||| Robert |||| — Preceding unsigned comment added by (talk) 02:02, 27 January 2014 (UTC)

Causes: inadequate dietary intake[edit]

Can anyone provide evidence of soil as a dietary source of B12 for human beings? I have found no such evidence. The only article I have found regarding B12 in soil states that these are B12 analogues, and makes no claim of them being bioavailable for the purposes of meeting human nutritional requirements for B12. If a citation is not provided, then I feel it should be stated clearly in this section of the article that the consumption of soil should not be relied upon as a dietary source of B12. I would also be interested in seeing studies where it has been proven that the consumption of soil can exist as the exclusive source of vitamin B12 in a human diet and not result in B12 deficiency. Thank you for your assistance.Ctconnolly (talk) 20:28, 17 February 2012 (UTC)

Here's the link to the article I have found regarding soil and B!2 analogues.Ctconnolly (talk) 23:36, 17 February 2012 (UTC)

Much of the content of this subsection of the article is off-topic or unsourced or both. This same topic is covered later in the article, with numerous online citations, in the section titled "Dietary sources of B12". I suggest removing much of the existing material in the subsection of "Causes" titled "Inadequate dietary intake of vitamin B12", and referring people to the section "Dietary sources of B12". Alternatively, the info in the section "Dietary sources of B12" could be moved to be merged with, and perhaps largely replace, what currently exists in the subsection "Inadequate dietary intake of vitamin B12" that exists within the section "Causes".Ctconnolly (talk) 22:04, 21 February 2012 (UTC)


"Epidemiology" The final two paragraphs of this section are written more like an argument than an encyclopedia. The statements may or may not be accurate, but should be rewritten to reflect more of a neutral point of view. Shadow308b4 (talk) 21:22, 27 February 2012 (UTC)

I have also found the tone in sections of this article to be incompatible with Wikipedia standards. I have undertaken some minor editing, but this issue needs to be addressed.--Soulparadox 10:25, 2 July 2012 (UTC)

Recent Edits[edit]

Hi all,

I updated the page a little by providing a few sources. One thing that I wanted to distinguish is that in humans, vitamin B12 is obtained through diet, however that isn't always the case for other species. For instance, herbivores are able to obtain adequate levels of B12 via bacteria that live within the gut. (From the same Voet & Voet source) I also removed a few things on the page as well. In regards to this sentence:

How much B12 is obtained from the diet; how much is secreted; and how much is absorbed. B12 deficiency may arise within the span of a year, if initial stores are low and genetic factors unfavorable—in contrast, a deficiency may not appear for a number of decades.

I removed it because the mention of genetic factors, initial stores, rate of depletion, absorption, and secretion has too many variables to make a solid conclusion, especially given that the statement is not cited. In addition, the wide range of deficiency from a year to decades is quite inconclusive. Let me know if you have any thoughts! Icestorm815Talk 03:52, 2 December 2012 (UTC)

Folate masking B12 deficiency[edit]

This does not make any sense to me. If folate AND B12 are required for production of healthy blood cells then how can extra folate mask the anemia from B12 deficiency? Considering that folate is required for the activation of B12 it would seem to me that extra folate may help the body to utilise what B12 is available more effectively. So how then would the neurological damage still progress?

This whole concept seems nonsense to me and the source for it is a badly written section in an article from the American "National Institutes for Health" How reliable a source is this? Unless something more concrete is cited I think this section should be left out. DrSparticle (talk) 00:55, 6 December 2012 (UTC)

Actually B12 isn't required for production of red cells. Or at least, not enough that the lack will be noticed by looking at the blood. Which is a problem, since B12 induced folate-anemia used to be a nice marker for B12 deficiency. With loss of folate, megaloblastic anemia wouldn't BE an anemia. But you'd still die of B12 deficiency-- as a pure neurological syndrome that is much harder to diagnose. The neurological damage would progress if you didn't have enough B12, that's all. Perhaps adding folate would help, but wiping out the anemia that has always gone along with B12 deficiency was seen as not being a very good idea, so it as argumed that folate should not be put in flour without B12, too. see here. See also here: [1]. This is not now being uniformly done, but for such reasons as put forth in the preceding paper, it probably will be. SBHarris 03:10, 6 December 2012 (UTC)

Claims of non-animal sources for B12[edit]

Again According to the U.S. National Institutes of Health: "natural food sources of vitamin B12 are limited to foods that come from animals."[1]

"Vegans need to look to fortified foods or supplements to get vitamin B12 in their diet." - Vegetarian Resource Group

"Contrary to the many rumors, there are no reliable, unfortified plant sources of vitamin B12, including tempeh, seaweeds, and organic produce. One of the earliest studies conducted on vegans, from the U.K. in 1955, described significant vitamin B12 deficiency in the vegans with some suffering from nerve damage and dementia. This, as well as many case studies since then of vitamin B12 deficiency in vegans, and a great deal of other evidence detailed here, has led to the overwhelming consensus in the mainstream nutrition community, as well as among vegan health professionals, that vitamin B12 fortified foods or supplements are necessary for the optimal health of vegans, and even vegetarians in many cases." - Vegan Outreach

To repeat that, "including seaweeds".

"Because plant foods do not naturally contain vitamin B12, unsupplemented vegan diets are theoretically completely lacking in this nutrient." - The Dietitian's Guide to Vegetarian Diets

"Tempeh, miso, sea vegetables, and other plant foods are sometimes reported to contain vitamin B12. These products, however, are not reliable sources of the vitamin. The standard method for measuring vitamin B12 in foods measures both active and inactive forms of vitamin B12. The inactive form (also called analogues) actually interferes with normal vitamin B12 absorption and metabolism (7). When only active vitamin B12 is measured, plant foods including fermented soyfoods and sea vegetables do not contain significant amounts of active vitamin B12 (8)." - The Vegetarian Resource Group

""There is no active vitamin B-12 in anything that grows out of the ground; storage vitamin B-12 is fouind only in animal products where it is ubiquitous..."; "Fermented products, such as soy products like twmpeh, do not contain substantial amounts of B-12."; "...there is practically no vitamin B-12 in (spirulinas)."; ""The vegan diet...contains no vitamin B-12 except trace amounts in some ... root nodules. Careful studies from England on several hundred vegans showed that they all eventually get vitamin B-12 deficiency disease with anemia and pancytopenia, low white counts, low red coundts, low platelet counts, and slowed DNA synthesis. Vegans all eventually have slowed DNA synthesis, Which is corrected by vitamin B-12." Vitamin B-12: plant sources, requirements, and assay, Am J Clin Nutr 1988; 48:852-8

Cites recently given to the contrary do not counter these simple declarative statements.

  • From feeding algae to rats: "The results suggest that algal vitamin B12 is a bioavailable source for mammals." Feedings to rats, not people, suggest, not demonstrate, algal B12 is a source for mammals, not humans. Compare this one study to the declarative statement of the NIH specifically discussing human diet...
  • Similarly: "These results suggest that Chlorella supplementation significantly reduces the risk of pregnancy associated anemia, proteinuria and edema. Chlorella supplement may be useful as a resource of natural folate, vitamin B-12 and iron for pregnant women." Results suggest the supplement reduces the risk of (various diseases) (which is synthesized into a claim that Chlorella is a reliable source of B12 for all humans.
  • Again: Chlorella tablets were subjected to chemical analysis which, in this one study, found B12. Bioavailable B12 for humans? It doesn't say.
  • "...several plant-origin foods including seaweed, soybean-fermented foods, and kimchi, may contribute significantly to good vitamin B(12) status in very old elderly Koreans." May good vitamin B12 status (among these particular Korean women eating an omnivorous diet).
  • "...the traditional foods, especially of fermentation, might be evaluated for compensation of the nutritional imbalance in the vegetable-oriented dietary pattern by supplying vitamin B(12), resulting in maintenance of health status." Might be evaluated... (If that sounds conclusive to you, you may be suffering from problems associated with B12 deficiency... That is not a conclusive statements about B12 being in fermented foods.
  • "A vitamin B12 compound was purified from the lyophilized purple laver and partially characterized. The silica gel 60 TLC and reversed-phase HPLC patterns of the purified pink-colored compound were identical to those of authentic vitamin B12..." using this to say the purple laver is a reliable dietary source of B12 for humans is original research.
  • "These results indicate that vitamin B12 in dried purple laver is bioavailable to rats." Great news for rats everywhere...
  • "A survey of 326 algal species revealed that 171 species require exogenous vitamin B12 for growth..." Now that we've found a source of B12 for those 171 sources of algae...

This is a continuing problem in various vegan and vegetarian articles, but the reliable sources are unequivocal. - SummerPhD (talk) 04:31, 6 December 2012 (UTC)

Now we have a weaselly, off-topic section, arguing against the reliable sources I cited above, trying desperately to say -- without saying directly -- "Hey! Look! Vegan remotely possible, unverified sources of B12!" Anyone care to actually discuss this? - SummerPhD (talk) 04:11, 8 December 2012 (UTC)
No, our DMZR editor adds and subtracts willy-nilly, but he doesn't like to discuss stuff with his fellow editors. I predict a poor future for him on WP. SBHarris 04:27, 8 December 2012 (UTC)

Regarding SummerPhd's comments: the vegan "resource centers" and various organizations you mention do not contstitute WP:reliable sources for scientific facts. As to your list of complaints about the sources in the article- lol you should actually read them. Half of your points disprove themselves as soon as you refrain from cutting off half the quote. Then with other complaints you simply searched each study for the most equivocating statements, ignoring the definite statements. And finally a few points you really don't seem to understand. [PA redacted - William M. Connolley (talk) 11:26, 8 December 2012 (UTC)] David Martin Zeegen Roth (talk) 06:46, 8 December 2012 (UTC)

If there is no further comment here, I am going to make a substantial change to this material to reflect the scientific consensus on this fringe claim. I will WP:MEDRS. - SummerPhD (talk) 15:58, 8 December 2012 (UTC)

Actually comments are still being made here and the changes you proposr sound invalid and unjustified. More shortly. David Martin Zeegen Roth (talk) 16:20, 8 December 2012 (UTC)

Information and quotes from vegan groups are not WP:reliable sources for scientific facts. This much is clear. But if these are noy reliable sources for scientific facts, then they are also not WP:reliable sources to justify suppressing scientific facts. A soldier who is not dependable enough to be sent to war you don't make a general.
And vegan groups are not WP:reliable sources for good reason. Take Jack Norris' popular article, "B12 in Tempeh, Seaweeds, Organic Produce, and Other Plant Foods," for example, which many of the groups paraphrase or directly quote. The crux of the article is Jack Norris' finding that that research on B12 in "nori" is self-contradictory. Whereas in reality the contradiction is merely the result of Jack Norris' failure to discern that two different species of nori had been studied by the scientists. That is a perfect example of why vegan groups, and for that matter Jack Norris himself, are not WP:reliable sources for scientific facts. David Martin Zeegen Roth (talk) 16:52, 8 December 2012 (UTC)
The U.S. National Institutes of Health and the American Journal of Clinical Nutrition are neither vegan groups nor in any way unreliable. I included the vegan groups as evidence that mainstream (non-fringe) vegan groups understand that natural sources of vitamin B12 only come from animal sources. Your analysis of the intersection between various sources is not useful in this regard. The NIH and Am J Clin Nutr are reliable sources without regard for what you believe their sources may be or your opinion of the validity of their conclusions. - SummerPhD (talk) 17:06, 8 December 2012 (UTC)

Wikipedia is an encyclopedia of real facts, not a coffee-table book showcasing the 'understandings' of various unreliable groups.

The NIH statement you quote cites as its source a document published in 1998, i.e. prior to the discovery of vitamin B12 in Chlorella and Porphyra yezoensis by the Japanese. A little matter called sequence in time.

About your mash of quotes from Am J Clin Nutr, do you mind giving me the proper citation or PMID so I can read the paper?

The first quote is funny though, "There is no active vitamin B-12 in anything that grows out of the ground..." Compare this statement by researchers in the Department of Plant Sciences at Cambridge in 2007: "Vitamin B12 is unique in that it is not found in vascular plants, but is abundant in algae" (my italics) (PMID 17434786)

The second and third quotes about tempeh and soy foods appear valid, but it should be noted that certain traditional Korean fermented soy foods have been recently been reported to contain vitamin B12. (see article:dietary sources)

The fourth quote about the vegan diet containing no B12 except from root nodules was disproven a little more than 10 years later when the Japanese discovered vitamin B12 in certain algae. (see above about sequence in time, and article) And with regard to what is promised to befall vegans in the quote, compare what was actually found in a 1984 study in which vegans' and vegetarians' blood counts were not appreciably different from those of non-vegetarians, even though some had been vegans for over 10 years. (see article, epistemology)

Lastly, what is my "analysis of the intersection between various sources?" Lol, do mean when I pointed out above that Jack Norris' article misleads readers by having them believe that only one "nori" was being studied in Japan?

David Martin Zeegen Roth (talk) 19:17, 8 December 2012 (UTC)

Yes, journal articles come out regularly. If they were all laid end to end, they still wouldn't reach a conclusion. The 1998 NIH statement is too old? [2] is 2011 (cancel the print pop-up if you get one, it's the only way I know to get the version date from NIH): "Vitamin B12 is found naturally in a wide variety of animal foods and is added to some fortified foods. Plant foods have no vitamin B12 unless they are fortified....Some people who eat little or no animal foods such as vegetarians and vegans. Only animal foods have vitamin B12 naturally. When pregnant women and women who breastfeed their babies are strict vegetarians or vegans, their babies might also not get enough vitamin B12." Again, "Only animal foods have vitamin B12 naturally." Yeah, various studies find this, that or the other. None of them, however, are indicating a reliable source of B12 in an unfortified vegan diet.
Wow. 10 years without B12 and they haven't exhausted their bodily stores yet? Why, that there is proof positive that they will never run out. At least those subjects didn't. So long as they are exact models of all of humanity and only live 10 years. Yes, B12 deficiency can take decades to surface. Or not. It's a risk you have to take if you're going to follow a fringe diet. Your "analysis of the intersection between various sources" is saying that a source isn't reliable because you believe their methodology and or sources are flawed. This is not how WP:MEDRS works. I'd explain that further if you were new here, but it seems you've edited under another name before starting this single purpose account. Care to clarify? - SummerPhD (talk) 20:07, 8 December 2012 (UTC)
I support the desire of SummerPhD to make substantial changes to the section of this article that relates to dietary sources of Vitamin B12. To my present understanding, the clearest biochemical, thus scientific, evidence of whether or not a digested substance can be deemed a reliable dietary source of vitamin B12 for human beings is to demonstrate that that substance can support normal levels of methylmalonic acid in the human body when that substance is used long-term as the exclusive source of B12 for that individual. I know of no such study that provides this evidence for any type of algae, indeed for any non-animal-based or non-B12-fortified substance. It would seem that this would be a simple, albeit lengthy, study to perform with individuals who are strict vegans. Periodic urine samples and complete dietary honesty would be all that would be required of the participants. The latter factor would likely be the more difficult to obtain. Treating B12 deficient vegans exclusively with any one chlorella or laver substance added to their daily diet could be a faster method of gaining evidence, yet I know of no physician who would ethically entertain such risks. The B12 article issued by the National Institutes of Health was reviewed by that leading scientific agency on 24 June 2011 and deemed valid by that agency. Their conclusion could hardly be clearer: "Only animal foods have vitamin B12 naturally". Perhaps the algal research could be placed in a separate, preferably subsequent, section titled something such as: "Research related to potential yet unconfirmed sources of bioavailable B12 for human beings." The authors of the first Korean study cited admit their results are inconclusive. And that article's abstract makes no claim that any of the individuals researched were strict vegans. In addition, serum B12 (their chosen method of testing) is not the gold standard for B12 testing; urinary methylmalonic acid testing is, to my understanding, the gold standard. Serum B12 can include measurements of B12 that are not bioavailable at the non-serum tissue and cellular levels. In other words, there may appear to be sufficient B12 in your bloodstream, but not enough actually feeding your nervous system. The authors of the second Korean study cited are explicit in their abstract in stating the the participants in the study were not vegans (they are described as "semi-vegetarian"). The first chlorella study cited makes no claims in its abstract that the B12 in chlorella can be relied upon as a dietary source of bioavailable B12. The second chlorella article cited was performed on rats, not human beings. The other foods consumed by the rats is not mentioned in the abstract. The focus of this Wikipedia article is on B12 deficiency in human beings, not other species. The third chlorella study cited makes no claim in its abstract that its participants were ever measured for B12 by any method. The first laver study cited provides no statements in its abstract that claim laver is a reliable source of bioavalable B12 for human beings. The authors of the second laver study cited state clearly that their conclusions apply exclusively to rats, as they were the only species tested. I would welcome the results of any peer-reviewed human clinical trials. Until such time, I would prefer that this chlorella and laver research be placed in a separate section of this article, if included at all. The content of this section as it existed at the time of my most recent edit, 21 February 2012, may be of inspiration to some other authors as they consider rewriting this section. Respectfully.Ctconnolly (talk) 05:40, 24 December 2012 (UTC)
We basically solved the problem that way in the B12 article and it can easily be adapted /copied to here. I'm not so worried about differences between rats and humans as the fact that even rat MMA studies haven't been replicated. So all this algae research is very preliminary. I suspect it will pan out but it's very far from being able to serve as a basis for Hunan dietary recommendations. SBHarris 19:24, 24 December 2012 (UTC)
To my understanding, there is still no scientifically-proven, naturally-occuring, non-animal source of bioavailable B12 for human beings. Thus I suggest the following passage be edited to agree with the existing scientific consensus:
"Vitamin B12 occurs in animal products (eggs, meat, milk) as well as in some algae, such as Chlorella[22][23][24] and Susabi-nori (Porphyra yezoensis).[25][26][27] Vegans and vegetarians to a lesser degree may be at risk for B12 deficiency due to inadequate dietary intake of B12, since they may not be aware of the few non-animal dietary sources of vitamin B12. However a 2000 Tuft study found not eating meat was not correlated with lower levels.[28] Children are at a higher risk for B12 deficiency due to inadequate dietary intake, as they have fewer vitamin stores and a relatively larger vitamin need per calorie of food intake."
What are the scientifically proven "non-animal dietary sources of vitamin B12" for human beings apart from man-made supplements? If there are none, then I think this statement should be removed from the article because some readers may incorrectly infer that this article supports the idea that the algae mentioned in the passage I quoted from the existing article are scientifically proven dietary sources of vitamin B12 for human beings. Your thoughts?Ctconnolly (talk) 00:20, 29 April 2013 (UTC)
Just my 2 cents (as biochemist): shouldn't it be clearly stated out that the the dietary sources indicated are secondary sources? Animals cannot synthesize vit B12, they take it from the environment (through association with Bacteria and possibly Archeae), hence in theory, they may also lack in vit B12 - think of a chicken in a cage, whose feed has no vit B12 (I know it is a remote possibility, but just as an extreme example)? My question is then: given that only bacteria can make the stuff, shouldn't fermented food considered as a source? I looked at the content in sauerkraut (traditionally, a source of vit C, which is made by a complex mix of bacteria responsible for fermentation, including Lactobacilli), but I could not find any evidence for it. Yoghurt, on the other hand, has appreciable levels of B12 (bioavailable, I checked in published research:, but whether coming from milk - which is a source in itself, or from the bacteria, I can't tell). Incidentally, soil is a good source of the bacteria that can make vit B12 (if you check the list given in the vit B12 wiki article:, many of those live in the soil) - not that I am advocating eating dirt, but maybe some animals do. I'll check how ruminants get their rumen bacteria... (talk) 13:51, 23 June 2013 (UTC)
According to the U.S. National Institutes of Health: "natural food sources of vitamin B12 are limited to foods that come from animals."[1] Some bacteria produce B12, just as some animals produce eggs. Expecting B12 from all bacteria is like expecting eggs from a cow. Where did the cow get the B12? How about bacteria in her rumen? As vegans are fond of pointing out bacteria in the human gut produce B12. As they are not fond of explaining, it's produced very low in the gut where the body cannot absorb it. Long story short: Reliable sources clearly state that the only reliable sources of B12 for humans are foods that come from animals and foods that have been fortified with B12. Everything else is vegetarians/vegans/fruitarians trying to find ways to make their unnatural diets natural. - SummerPhD (talk) 15:13, 23 June 2013 (UTC)

Plants may contain traces of active cobalamin but the plants themselves don't produce it, they are secondary sources that accidentally soaked up some B12 (e.g. from animal droppings) and that's what makes them an unreliable source. Secondly these traces tend to be unsubstantial amounts and the presence of other B12 analogues may inhibit the uptake of the little active cobalamin that is present. So, for a reliable source we also need to know that there is a substantial amount of active cobalamin and at most a negligible amount of analogues.

If you are looking for research to cite for a reliable source of B12 look for MMA results (preferably a uMMA test) and make sure that a decrease in MMA was observed or that the change in MMA was compared to the intrinsic factor (although it is better to know the cause of B12 deficiency for reliable results) and and substantial number of people must have finished the trials - not just a few people who possibly didn't follow the diet as strictly as they should have or whose lack of hygiene rewarded them with just enough B12 or whose MMA test happened to be one of those false-positives.

Okay, I could go on endlessly about how to vet someone's research but it's often better to wait until someone does it for you and publishes his findings on the matter - a.k.a. a secondary source. Wikipedia is usually not a place where you should expect to find the latest of research but instead the somewhat more limited scope of "this is what we know for certain." JGM73 (talk) 19:25, 28 November 2013 (UTC)

Material removed[edit]

However, vegans should be aware that supplemental B12, such as that added to fortified foods, has been found to degrade rapidly and may contain varying levels of pseudovitamin-B12.ref name="Yamada K 2008" Yamada K, et al. (2008) "Degradation of vitamin B12 in dietary supplements." Int J Vitam Nutr Res. 78 (4-5): 195-203. PMID 19326342/ref refHerbert V, et al. (1982) "Multivitamin/mineral food supplements containing vitamin B12 may also contain analogues of vitamin B12." New England Journal of Medicine 307 (4): 255-6. PMID 7088084 /ref.

Sorry, but the first article is a preliminary paper on B12 in *beverages,* (where it might be expected to degrade faster) and the other is an old 1984 paper which makes a suggestion about B12 in pills which has never been duplicated. Herbert et al. were suggesting that perhaps B12 in pills was turning into pseudo-B12, but this was never quantified (what fraction is it?), and nobody since has done so, or suggested that B12 in multivitamins or dedicated B12 pills is not to be trusted. On the contrary, there have been many reports of successful treatment of pernicious anemia in humans with oral supplements alone [2]. Though higher-than-normal doses are needed,[3][4], doing this is still spectacular, and is not something you will find anybody has done with Chlorella or Susabi-nori (purple laver).

So why are we going on and on about this? Has the B12 from Chlorella proven to be bioactive in any mammal? No? Then why mention it as a dietary source? The susabi-nori (Porphyra yezoensis) looks promising from what I can see, and just as soon as a few clinical studies IN HUMANS who are short of B12 have been done with it, it might be recommended for those with fat wallets and a horror of bacterial products. Meanwhile it's not ready for prime time. Paricularly as you'd have to eat about a kilo of the fresh seaweed to get as much B12 as there is in one 500 mcg B12 pill that costs about 5 cents. There is a reason for these concensus recommendations from vegetarian societies, and it's not to make B12 pill makers a lot of money. The pure cyanocobalamin is made by the ton. To push B12 made by seaweed algae vs. B12 made by bacteria, is perverse. Bacteria and their products are as vegan as it gets. All B12 in pills is vegan already. Dried susabi nori (Porphyra yezoensis is the same stuff used to wrap your sushi, just dried), on the other hand, is about 50 cents a gram (Eden-Foods-Nori-Krinkles-Toasted-Sea-Vegetable-0-53-oz-15-g from iHerb) and if (when dry) it's 10 parts per million B12, you can do the math. It would cost you about $25 to get 500 mcg of B12 (what's in ONE pill of dedicated B12), and that's if the nori-B12 is good B12-- which we don't know.

Anyway, I'm not adverse to adding a little interesting stuff about "maybe sources" of algae B12 that might be coming up. In their own section, and clearly labeled as "research". But this is not stuff we want people doing instead of buying the reliable 5 cent cyanocobalamin pill. That's damaging original research, and even if it proves out to work in the future, it's still a horrid waste of money. Bacterial fermentation source B12 will always be far cheaper than dried seaweed. SBHarris 04:23, 8 December 2012 (UTC)

Unjustified. The first study is not only on beverages, but on fortified beverages and solid foods. The second study found that supplements containing B12 may aslo contain Pseudo-B12. Enough said. The statements in the article in no way go beyond the conclusions of the studies themselves. All your talk that the current price of B12 should influence whether citable facts get suppressed or not is not even worth replying to. [PA redacted - William M. Connolley (talk) 11:26, 8 December 2012 (UTC)] -David David Martin Zeegen Roth (talk) 06:01, 8 December 2012 (UTC)
There were no solid foods, only four solid supplements. One of these four was found to have less B12 than on the label. You want us to make what generalization about all solid fortified foods based on one measurement for one supplement in one study?? SBHarris 19:00, 8 December 2012 (UTC)

I'm not exactly clear as to your question. The article gives a simple factual summary of what the studies found, i.e. that supplemental B12, such as that added to fortified foods (beverages included), degrades rapidly in time and may contain varying levels of pseudovitamin-B12. You are right that the 'solids' in the study were solid B12 dietary supplements instead of B12-fortified solid foods, however the article gives an accurate description of the findings. You should produce either citable facts indicating that supplemental B12 added to fortified solid foods is different from supplemental B12 added to fortified beverages, or else a study finding that supplemental B12 added to fortified solid foods does not degrade.

David Martin Zeegen Roth (talk) 20:47, 8 December 2012 (UTC)

I don't have library access from home, but from what little I can see, there are a few problems.
  • Having previously having been warned, blocked and warned again for edit warring, you are repeatedly undoing more than one editor's removal of the material. While discussing it here is a good start, insisting that your opinion is the "right version" while it is being discussed is problematic.
  • "Vegans should be aware..." is probably an unsourced interpretation.
  • The first source discusses 5 beverages and 4 solid supplements. One study with limited data calls for caution on our part. The strong wording in the section has got to go.
  • I see no indication that degradation was found in the supplements. "On the other hand, certain beverages unexpectedly contained much more B12 than stated on the labels. In these beverages the amount of B12 decreased rapidly with time, whereas B12 content was lower than stated on the label in only one of four solid dietary supplements. The content of B12 was affected by storage time, light exposure, temperature and vitamin C." To me, that is clearly discussing only the beverages.
  • The second source seems to have nothing to do with this portion of the text. Citing it as you have seems to imply it supports both portions of the text. If nothing else, this should be clarified.
  • "...may contain varying levels of pseudovitamin-B12." This mischaracterizes the first source which discusses conversion to B12 analogues which "might" have occurred. Again, we have one study with a very small sample size (and careful wording to boot). From this we are saying vegans "should be aware"? No, I think not.
To fully explain what you are trying to add here and how you are supporting it, I would suggest breaking your addition down into discrete facts and quoting the specific wording in the source that you feel supports it. After discussion and a reasonable consensus, we might have something to add. - SummerPhD (talk) 21:39, 8 December 2012 (UTC)

probably added by a vegan[edit]

though data from WHO publications on world food consumption point to a large deficiency of poor populations in consuming adequate amounts of fresh fruit and vegetables, which carry B12 from bacteria in the soil they are grown in, so this is likely a primary cause as well, since vitamin B12 does not originate from animal sources and can be obtained without consuming animal products.[71]

I read the source. The WHO states that poor populations lack fresh fruit and vegetables, but it is not stated anywhere that soil carry B12. AFAIK the WHO does not officially endorse soil as source of B12, and it is misleading to imply so (moreover, I can't see how fruit would carry soil. I'd rather not buy a fruit that fell to the ground). Delete. — Preceding unsigned comment added by (talk) 16:41, 17 June 2013 (UTC)

  1. ^ a b "Dietary Supplement Fact Sheet: Vitamin B12". National Institutes of Health: Office of Dietary Supplements. Retrieved 2009-11-13. 
  2. ^ Lederle FA (September 1998). "Oral cobalamin for pernicious anemia: back from the verge of extinction". Journal of the American Geriatrics Society 46 (9): 1125–7. PMID 9736106. 
  3. ^ "Pernicious Anemia and B12 Injections". Retrieved 2008-01-27. 
  4. ^ Butler CC, Vidal-Alaball J, Cannings-John R et al. (June 2006). "Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency: a systematic review of randomized controlled trials". Family Practice 23 (3): 279–85. doi:10.1093/fampra/cml008. PMID 16585128.