More B12 Claims

An activist brought to my attention the article B12 Deficiencies in Vegans? Not True! at Flaming Vegan. I was surprised to read the article and the comments, and so I posted some comments of my own below it.

Another reader brought my attention to a page claiming that miso is a source of vitamin B12 and that chlorella is the “best source” of vitamin B12.

As for miso, the two published studies that have measured vitamin B12 in miso have found none. As for chlorella, two studies have found vitamin B12 in batches of chlorella while one study found practically none. Chlorella might be a source of vitamin B12, but there has yet to be any studies in the scientific literature to determine if chlorella can improve vitamin B12 status (see B12 in Tempeh, Seaweeds, Organic Produce, and Other Plant Foods for citations).

It is not clear why chlorella would have vitamin B12 – whether through contamination or because it actually produces it, and because of this, multiple batches from different locations should be tested before there is any certainty that it is a reliable source.

It should also be noted that the second link above lists romaine and arugula as sources of calcium. According to the USDA, one cup of shredded romaine has only 15 mg of calcium and one cup of arugula has 32 mg of calcium. So if you are going to rely on either for calcium, you will need to eat many servings.

42 Responses to “More B12 Claims”

  1. John Says:

    Thanks Jack! I didn’t supplement b12 for years until I came upon your B12 page in 2004. I could have ruined my health

  2. M;ichael Says:

    HI Jack!

    I don’t know how much a cup is, but here in Germany arugula is measured with having 160 mg of calcium per 100 gr. And one can easily eat a smothie with 150 gr. and some sweet fruit.

    thanks for your work!

  3. Marion Says:

    I also have you to thank for your helpful, essential nutritional advice that has kept me healthy and happy over the years. I have followed your recommendations to the letter.
    I advise everyone to take nutritional advice from properly credentialed professionals. There is a lot of misinformation out there from people who have no real expertise or proper education. Evidence-based vegan nutrition as guided by a registered dietician is the only way to go. Vegan for Life is my bible!

  4. Mimi Says:

    According to 100g of arugula has 160mg of calcium and 100g of broccoli only about 50mg. So it looks like it’s not such a bad source?

  5. Jack Norris RD Says:

    Mimi & Michael,

    A cup of arugula is 20 g, so 100 g is 5 cups. A cup is equal to 237 ml, so 5 cups equals about 1.2 liters.

    Uh-oh, it looks like the USDA might have lowered the amount of calcium for broccoli. It used to say 50 mg per 1/2 cup of “Broccoli, cooked, boiled, drained” but now it is only listing 31 mg. A cup of chopped broccoli is 156 g and according to the current USDA database, only 62 mg of calcium. Broccoli was already on the lower end for leafy greens, but that really lowers it value for calcium considerably. I’ll have to look into that more and see if any other leafy greens were changed with the latest database release (which was last October).

    In any case, it’s a good point that using large amounts of arugula for smoothies can boost the calcium amount.

  6. Abi Says:

    Thank you for this, Jack.

    Vegan for Life will certainly help me and my daughter to be just that. Misinformation does our ’cause’ no favours.

    This continuation of the theme will hopefully help more people to realise sensible vegan nutrition is not hard, it is honest!

    Thank you again.

  7. The Healthy Librarian Says:

    Thanks for all your excellent research on vegan nutrition. Vitamin B-12 is so important–and even more so as we age.

  8. Mimi Says:

    Thanks for the explanation, Jack! I am in Europe and we measure everything in grams. I often find arugula listed as an excellent source of calcium. But it makes sense that it’s easier to eat the broccoli. Thank you for your great work!

  9. Maria Says:

    Even though some could find my comment not vegan, I refuse to take chemical supplements. Shellfish like cockles and mussels are the best natural source of vitamin B12. They are animals but they do not have brain. probably a vegetarian diet not so clean could provide this vitamin too. Herbivores eat many insects and vegetable mould with their food.

  10. Lauri Boone Says:

    Thank you for continuing to bring attention to this important topic. I have also heard some prominent vegan diet advocates erroneously tell their followers in recent months that they can obtain adequate B12 in their diets by simply NOT peeling fruits and vegetables and only washing them gently. Not true! It is so incredibly easy to supplement with B12. Thanks again for bringing attention to this and for your great work.

  11. evelyn Says:

    Thanks for this – I see a lot of this misinformation. I’ve posted your article to all of my social networks. Get the word out!

  12. Joe Espinosa Says:

    This may take us back to the begining in more ways that one, but I need this tidbit of information. Is soil (from unwashed plant foods) a reliable source of B-12? Without solid information on this Chicago Vegans could be dying 😉

  13. Jack Norris RD Says:


    > Is soil (from unwashed plant foods) a reliable source of B-12?

    Absolutely not.

  14. Jim Says:


    To put Joe’s question into perspective, so that Joe does not misrepresent your position on this: Nobody is suggesting that modern humans eat unwashed dirty vegetables to obtain B12, as Joe appears to be asking. The real question is, until modern times, did humans obtain B12 the same way other animals have, through eating unwashed vegetation? For instance, the Papua Highlanders (vegetarian) have not gotten their B12 through eating animals, but through the same way other herbivorous animals have in the Papua Highlands. Care to weigh in?

  15. Jack Norris RD Says:

    Hi Jim,

    Before answering your question, I decided to do some checking on the Papua New Guinea highlanders (PNGH).

    You can see Table 1 in this study showing that as of 1978 they were eating small amounts of meat and fish:

    Interestingly, this study’s abstract shows their B12 levels to be higher than the average Australian:

    I have not seen any evidence that soil has been a source of B12 physiologically important amounts. My sense is that all traditional human societies have eaten some animal products, whether that be mammals, birds, fish, amphibians, insects, grubs, dairy, or eggs, and that is how they have obtained the majority of their vitamin B12. Many other species of animals eats feces and can obtain vitamin B12 that way; I do not know if this has ever been a practice of humans (and if they had access to animal products, it wouldn’t have been necessary).

    The fact that the PNGH’s B12 levels could be so high is perplexing – perhaps they adapted an ability to conserve B12 better than your average person today, maybe they have eaten more animal products than we know about, or perhaps they have been able to get it from soil or some other fecal contamination, or their own gut bacteria.

    But to answer your question, I have not seen evidence that soil is a source of B12 that is active for humans in physiologically important amounts. You might be interested in the section Soil and Organic Produce as a B12 Source for Vegans of my B12 article.

  16. Scott Trimble Says:

    Is algae a better way to get B12 than from pills?

  17. Jack Norris RD Says:


    Are you just messing with me? 🙂 The whole point of my response to the Flaming Vegan article was to say that you cannot rely on algae or seaweed for vitamin B12.

  18. Julia Says:

    @ Maria – that’s an odd conclusion. Bivalves (what you refer to as “shellfish”) do have a sensory/nervous system, and although they do not have a hunan brain, they do have a simpler bivalve version called ganglia. Of course, your comment is not vegan! Please learn the definition of veganism. Compassion does not discriminate on species, especially because of your selfishness to not take a b12 supplement. Your logic insults and belittles the commitment that vegans make to all animal species and further perpetuates the misconception that vegans eat animal products when no one is looking. Regardless, who would want to eat bivalves, anyway? Do you realize they are basically the garbage cleaners that accumulate all the chemical pollution humans throw in the ocean?

  19. Jack Norris RD Says:


    While I am with you in opting for a supplement over eating bivalves, for people who will not take a supplement, I’d rather they were eating bivalves than mammals, birds, or fish.

  20. Phillippa Bennett Says:


    I’m currently reading and enjoying ‘Vegan for LIfe’ – thank you. Quick question – I drink B12 fortified soya milk (Alpro) every day and take a multivitamin with more then the RDA of B12, but it’s not a chewable tablet and has to be swallowed whole. Is that a problem in terms of accessing the B12?

  21. Jack Norris RD Says:


    Unless you think the tablet is not dissolving in your gut, it shouldn’t be a problem, especially since you are also drinking the soy milk daily. My sense is that multivitamin manufacturers have been doing a better job in recent years of making sure their tablets dissolve easily. You could crush it and put it in a drink or something, to make absolutely sure. Personally, I swallow tablets whole and just assume they get dissolved.

  22. Jim Says:


    That’s the great thing about internet debates/discussions, they push you to go out and do reading and research and, ultimately, you learn.

    In my “discussion” with someone on another board, I found this write up on B12 and found it to be very unbiased, unemotional, and it seems rather fact based. What one might be able to extrapolate is that it is not necessarily soil that contains B12, as much as it is “organic matter” that contains B12. The Papua Highlanders may use their own waste or animal waste to fertilize their crops. In this other discussion, I was recanting an article I read years ago on the domestication of the strawberry and how strawberries that grew from seeds passed in the excrement of humans 1000’s of years ago would cross pollinate and become a standard variant. As with many fruits, the seeds pass through the digestive system and are excreted. In waste areas where small family units would pass their waste, these areas would eventually become gardens of edible plants. Human waste, according to this article, has a very high amount of B12.

    Interesting stuff.

  23. Jim Says:

    Sorry, here’s the study.

  24. Jack Norris RD Says:

    Hi Jim,

    I cite that paper regarding the Iranian villagers on the page I referred you to Soil and Organic Produce as a B12 Source for Vegans.

  25. Jim Says:

    I have you seen this one on pond/lake water?

  26. Jack Norris RD Says:


    I have not seen that study on pond water, thanks for passing it on.

    I think it’s safe to say that anywhere that there is fecal contamination, such as in a lake where animals are presumably excreting, there should be some level of B12 found.

  27. Jim Says:

  28. Jack Norris RD Says:

    This discussion about chlorella reminded me that (quite) a few years ago, the UK Vegan Society was doing a trial to see if chlorella was a source of active vitamin B12. After emailing around, I found that they had reported on the trail in the Autumn 2005 issue of their newsletter The Vegan (p. 30). They considered the trail “inconclusive” but the one person who stayed in the trial and supplemented with chlorella did see a normalization of MMA levels.

  29. Jim Says:

    Here’s my completely uneducated, unofficial, and unscientific theory:

    Until we started living in the semi-sterile world we live in, humans since the dawn of time have been able to easily maintain their B12 levels, whether through animal consumption, unsanitary contamination, and/or through organic matter on vegetables, fruits, and berries that sprout up in common waste areas from seeds that passed through the digestive tracts of the people within the family/village units. As one of the studies demonstrated, it would take years for an individual to become B12 deficient, but it only takes a very small amount of fecal matter to bring that individual back up to optimal levels (did I read this right?). This fecal contamination could come through primitive sanitary conditions and/or through unwashed fruits and vegetables from gardens fertilized by organic waste. Because modern humans use toilets, outhouses, etc, we no longer have the benefit of the naturally growing gardens of fruits and vegetables that would grow over waste areas where the family units would expel their waste. Fruits and vegetables grown in human waste would likely be loaded with B12, wouldn’t they? Not in the flesh of the fruit or vegetable, but on the soil coating the fruit or vegetable. The interesting thing to know would be, where did humans traditionally get the majority of their B12, animal foods or through fecal contamination? Given the very high amounts in fecal matter, versus the low amounts in animal flesh, it might not be what one would initially think.

    Or is this theory all bovine fecal matter?

  30. Jack Norris RD Says:


    I don’t think there is any reason to think there is B12 in “organic matter” in general. In feces-contaminated organic matter, yes.

    > but it only takes a very small amount of fecal matter to bring that individual back up to optimal levels (did I read this right?).

    I’m not sure where you read that, but no, it does not sound right. If you read it here:

    I have added a sentence to clarify the 1951 study by Callendar & Spray:

    “The B12 was isolated from the stool samples and given to the subjects intravenously.”

    > Fruits and vegetables grown in human waste would likely be loaded with B12, wouldn’t they?

    Doubtful. They might have some, but not “loaded.”

    > The interesting thing to know would be, where did humans traditionally get the majority of their B12, animal foods or through fecal contamination?

    What reason is there to think it wasn’t through animal foods?

    I don’t really understand the effort to figure out how humans evolved as vegans. Humans had no reason to evolve as vegans. Animal rights was not a moral dilemma for humans as we evolved, and we ate whatever we could get our hands on that could be made edible.

  31. Jim Says:

    I am not suggesting humans evolved as vegans. Being vegan is not natural to humans. We are omnivores. We eat plants when plants are readily available and we eat animals when animals are plentiful. To suggest otherwise, and I have seen many try, is silly.

    I am also not suggesting that humans haven’t traditionally gotten B12 from animal foods. I am just suggesting that maybe it hasn’t been the primary source of B12. It’s interesting how humans produce B12, but only in the lower digestive tract, where it is not absorbed, and how contamination through organic matter (nice way of saying poop) is actually a source of B12.

  32. Jack Norris RD Says:


    Yes, you have a new and interesting twist on the idea – I will give you credit for that. And a new definition of “organic matter” as well. 🙂

  33. Paul Borst Says:


    As always, thanks for all you do. I just wonder about the testing alternative. Let’s suppose I’m a vegan who takes chlorella and says “I don’t like supplements” and there are studies that say chlorella has plenty of active B-12. Moreover the anecdotes in this thread plus the one case of someone you pointed out in UK Vegan Society Trial (2005) shows MMA has been normalized with people eating chlorella (note: that is different than saying chlorella normalized it, I’m splitting hairs here, but I want to be clear.) And then wouldn’t it be prudent for someone who hates supplements but wants to be safe just to take an MMA test. Don’t need a doctor’s order.

    just $120, some money up front but if you know that your body if taking the chlorella and reducing your MMA, you don’t have to keep buying the supplements. Over a lifetime, I think that’d be ok. Just an option.

    One more thing Jack, could you comment on the 2010 on chlorella reducing edema, anemia and improving the status of pregant women in Japan. I realize this has nothing to do with homocysteine but it just seems to me that this study has to be factored in to the total weight of evidence.

    As always a fan. Be well.


  34. Jack Norris RD Says:


    > And then wouldn’t it be prudent for someone who hates supplements but wants to be safe just to take an MMA test.


    > One more thing Jack, could you comment on the 2010 on chlorella reducing edema, anemia and improving the status of pregant women in Japan.

    I suppose it was the iron in the chlorella. I’ll put it in the queue to get a copy of the study and check it out.

    I do think that it would be really odd for chlorella to turn out to be the only known plant that produces its own vitamin B12, though stranger things have happened. I don’t know that it really means much for veganism being natural unless all humans consumed large amounts of chlorella as we evolved.

  35. Jack Norris RD Says:

    > only known plant

    Technically, chlorella isn’t really a plant, but you know what I mean – non-bacteria.

  36. Paul Borst Says:

    Right. And I agree veganism isn’t natural. We didn’t evolve as vegans. I think you put your finger on it above when you said we pretty much had to eat whatever we could find. Even bonobos eat insects as do gorillas. Veganism is a lifestyle established through personal conviction and decision to end or limit animal suffering, not a natural condition we evolved under.

    I personally don’t mind supplements. Some even consider chlorella a supplement. But I do like to know what my options are. And I want to find if there are any plants that contain B-12 and can reduce MMA. Purple laver as a sea vegetable is the only other one that can make that claim. No matter.

    It’s not just b-12. It’s zinc, iodine, vitamin-D and omega 3s also. Fortunately these aren’t as problematic to get from whole foods (Vitamin D being the exception).


  37. Jack Norris RD Says:

    > Purple laver as a sea vegetable is the only other one that can make that claim.

    In the 1999 study by Yamada, MMA levels went up in subjects eating laver (nori). The researchers concluded that because the levels in the group receiving raw nori did not increases significantly, it was a source of vitamin B12, but their levels did go up a bit.

    Are you aware of other research?

  38. Ava Odoémena Says:

    “Right. And I agree veganism isn’t natural. We didn’t evolve as vegans.”

    Well I think this is wrong in the most funny of ways! As if this present, and with it vegans, weren’t part of evolution. It’s shows a significant lack of understanding of evolution to equate “natural” with evolution. The ability to make ethical choices is just as part of human evolution as technology.

  39. Name Says:

    Jack, I’m a huge fan of your work. You + Michael Greger were the reasons I started supplementing my vegan diet with B12 on a regular basis.

    There’s one detail I’m confused about which I’m hoping you could answer. Haptocorrin binds about 80% of the B12 in circulation, while transcobalamin II binds the other 20%. The B12 attached to haptocorrin is known to be inactive. So if you have a serum B12 test done, is it detecting the B12 bound to haptocorrin? If so, why do so many medical professionals test serum B12 in the first place rather than just transcobalamin II?

  40. Jack Norris RD Says:


    > The B12 attached to haptocorrin is known to be inactive.

    Here is my understanding: transcobalamin II (TC2) has low affinity for inactive B12 analogues, while haptocorrin has a high affinity. However, unless someone is eating large amounts of seaweed, most of the B12 on haptocorrin in the blood should be active. The B12 on haptocorrin cannot be transported to the tissues unless it is transferred to TC2, but as someone develops B12 deficiency, it is my understanding that B12 is slowly transferred to TC2 at which point it can be delivered to the tissues.

    I could not verify how this transfer happens, but a fairly decent guess is that a certain portion of haptocorrin finds it’s way to the liver and into the enterohepatic circulation (i.e., it is secreted into the digestive tract). In the digestive tract, haptocorrin is degraded and the B12 is picked up by TC2.

    Thus, low levels of TC2 can indicate a developing deficiency, but the absolute amounts of B12 in the blood will tell you more of the story and how close someone is to becoming completely depleted.

  41. Jenna Says:

    Hi Jack

    I take a Deva DHA/EPA supplement a few times a week which is derived from algae. I also drink a green smoothie daily that has spirulina in it. I opt for the 2x a week dose of 1000 mcg sublingual for my b12. Will drinking these green smoothies with spirulina and taking the algae DHA a few times a week impact my absorption of b12. From what I understand from your post–eating large amounts of seaweed could make b12 inactive. Could the amount of algae based items I am eating impact my b12 absorption? Thanks so much for all that you do in bringing information to the vegan community!

  42. Jack Norris RD Says:


    The DHA won’t be a problem. The spirulina could be but it depends on how much you take, and I don’t know how much is too much. I don’t think there is any sort of wave of spirulina-induced B12 deficiency so normal amounts are probably fine. But I also don’t see any reason to take spirulina – none of the hype about it has any solid evidence, to my knowledge.

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