The Vitamins that Every Vegan and Vegetarian Needs

The Vitamin Everyone on a Plant-Based Diet Needs

A new study from China found that compared to omnivores, those who ate egg-free and meat-free diets had all the typical benefits of eating more plant-based: lower body mass index, lower blood pressure, lower triglyceride, lower total cholesterol, lower bad cholesterol, less free radical damage, etc. Having said that, if those on plant-based diets don’t get enough vitamin B12, levels of an artery-damaging compound called homocysteine can start to rise in the bloodstream and may counteract some of the benefits of healthy eating.

In a study profiled in my video, Vitamin B12 Necessary for Arterial Health, a group of Taiwanese researchers found that the arteries of vegetarians were just as stiff as the omnivores and both had the same level of thickening in their carotid arteries, presumably because of the elevated homocysteine levels. The researchers concluded:

“The negative findings of these studies should not be considered as evidence of neutral cardiovascular effects of vegetarianism, but do indicate an urgent need for modification of vegan diets through vitamin B12 fortification or supplementation. Vitamin B12 deficiency is a very serious problem leading ultimately to anemia, neuropsychiatric disorders, irreversible nerve damage, and high levels of artery-damaging homocysteine in the blood. Prudent vegans should include sources of vitamin B12 in their diets.”

One study of vegetarians whose B12 levels were really hurting found that they had even thicker, more dysfunctional arteries than omnivores. How do we know B12 was to blame? Because once they were given B12 supplements they got better. Their arterial lining started to shrink back, and the proper functioning of their arteries returned.

Without B12 fortified foods or B12 supplements, omnivores who were switched to a vegan diet developed vitamin B12 deficiency. Yes, it may take our blood levels dropping down to around 150 picomoles per liter to develop classic signs of B12 deficiency, like anemia or spinal cord degeneration, but way before that, we may start getting increased risk of cognitive deficits and brain shrinkage, stroke, depression, and nerve and bone damage. The rise in homocysteine may attenuate the beneficial effects of a vegetarian diet on cardiovascular health. The researchers concluded that while the beneficial effects of vegetarian diets on cholesterol and blood sugars “need to be advocated, but at the same time efforts to correct vitamin B12 deficiency in vegetarian diets can never be overestimated.”

I have dozens of videos on B12. For a quick cut-to-the-chase see my Q&A What is the best way to get vitamin B12? and for some context Vegan B12 deficiency: putting it into perspective. Vitamin B12 supplementation with fortified foods or supplements is critical on a plant-based diet.

-Michael Greger, M.D

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

146 responses to “The Vitamin Everyone on a Plant-Based Diet Needs

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  1. I’ve watched ALL of your videos on B12, and read everything posted on this website that pertains to B12, but do not see any mention by you discussing the possibility that B12 supplements do not work for some people due to genetic issues/defects, and therefore a need to do the “MTHFR test” or other related genetic tests to find out why the body is not benefiting from B12, and why these supplements might be causing them bad reactions as well. I do not understand the science of this genetic issue, but I know for me that B12 supplements cause severe adverse reactions in me, all forms, all injections, those without sweeteners, with sweeteners, with dairy, without dairy, different doses, – you name it , B12 supplements make me feel way worse than without.

    And I know of plenty of others who have great difficulty with B12 supplements as well, and have said that it is a “genetic issue” that must be addressed. Dr. Greger, do you have any knowledge of this MTHFR issue, and/or science related to that will help those who have issues with B12 supplements? I want to be 100 vegan, and know of plenty of others who do as well, but they have not been able to find the missing link to why B12 pills are not working, and/or causing them bad reactions.

    1. Individuals bearing some very common MTHFR polymorphisms (eg C677T or A1298C) don’t have impaired B12 metabolism. Instead, they have up to 70% less activity of MTHFR, an enzyme in the folate cycle required to reduce methylene-THF to methyl-THF. In the methionine cycle, the methyl is transfered from methyl-THF to homocysteine, to reform methionine by an enzyme which uses B12 as a cofactor. Here’s showing how the two cycles relate.relate.

      In practical terms, this means individuals with MTHFR mutations may need consume more biologically active folate to compensate. Natural folate is ubiquitous in plant foods, especially green leafy vegetables, legumes, and the germ of grains. However, it isn’t shelf-stable, so synthetic folic acid is used in supplements and to fortify processed foods like flour and breakfast cereals. Humans have a limited and variable capacity to convert folic acid to active folate, and some take supplements of a shelf-stable form of biologically active folate (Levomefolic acid, tradmarked Metafolin and Deplin), which is more bioavailable than folic acid. The amount of levomefolic acid in supplements (400-1000 μg) is comparable to the amount of folate in whole plant based diets, and those eating a lot of leafy green vegetables and greens can do significantly better.

      1. Thanks for this. Am I understanding this correctly that individuals with this MTHFR polymorphism issue are not processing the methionine correctly/efficiently and are therefore ending up having it remain as homocysteine (not getting converted back to methionine), thus, they end up testing very high in serum homocysteine?

        1. Right. With impaired MTHFR activity, the folates build up as methylene-THF, and only the amount that eeks through MTHFR to methyl-THF are available to remethylate homocysteine back into methionine.

          I should add that there’s good reason to suspect that the association of elevated homocysteine with cardiovascular disease is a coincident marker of too much high-methionine animal protein and not enough folate containing greens in the diet. Genetic predispositions to lifelong moderately higher homocysteine (like the C677T or A1298C polymorphisms) have little or no effect on cardiovascular risk. Homocysteine lowering interventions, including folic acid supplementation, have no significant impact on CVD risk. In animal studies, high methionine intake increases homocysteine, but is also sufficient to increase atherosclerosis even in the absence of elevated homocysteine. A study of the common MTHFR C677T polymorphism, which lowers levels of methyl-THF and elevates homocysteine, suggests that the homocysteine may just be a marker of low methyl-THF status, which has a more direct role in atherosclerosis. Folate has a lot of cardiovascular benefits apart from remethylating homocysteine, perhaps mediated by quenching the peroxynitrite-derived radicals which cause ischemia/reperfusion injury. The title of this review almost says it all. I would have used “How does folate cure heart attacks”.

          1. Interesting and just a tad over my head, but I do get the gist. However, I don’t understand why Elsie’s issues with folic acid would cause the shellfish to mitigate her symptoms.

            1. For now I am guessing that the B12 in the shellfish is being absorbed by my body and utilized effectively, and for whatever reason B12 supplement/injections are not. Maybe my (and others’) inability to benefit from B12 supplements has nothing to do with the MTHFR/folate issue?

              Interestingly, my serum folate level is great.

          2. What role does B12 play in this, and why do people feel this (MTHFR issue) is why they have an issue with being able to digest, absorb, utilize, etc. different forms (or any) of B12? The way it was explained to me by my doctor was that “B12 is a necessary component to allow for many different and multi-layered reactions in the body, and some of these reactions are not even the ones we commonly talk about.”

            I’m guessing from what you’ve said already, a humans ability to absorb/digest/fully utilize a B12 supplement has nothing to do with having this MTHFR issue?

          3. Darryl: Thank you for answering this question. I know someone who was asking me this very question the other day. Now I have much better information for her. So, you have already helped more than one person. Thanks!

        2. Elsie, I’m wondering if your level of healthy gut bacteria is not enough to allow for B12 to get into the bloodstream. I recall one person who had to eat animal foods to get his B12 levels up. When I worked with him to reduce his consumption of meat, I recommended probiotics supplementation at double the usual dosage for 2 months. It did the trick, and his B12 levels were very good. He has it checked every 6 months, and if B12 is dropping, he does another round of probiotics. I generally recommend the human micro flora type of probiotic, not the bovine type. To be vegan, take it in powdered form, just mix it into smoothies, cold drinks, water, etc. You need to keep it refrigerated.

          To understand why I think it could be an issue of healthy bacteria levels in the gut, here’s a link to an article that may help:

          And here’s a quote from that article:
          “Probiotics are the new vitamins,” says Shekhar Challa, MD, a gastroenterologist in Topeka, KS, and the author of Probiotics for Dummies. That’s a bold statement, because probiotics are actually live microbes—specifically, beneficial bacteria that promote human health if consumed in large enough quantities. For germophobic Americans, it’s a revolutionary concept. But the 100 trillion microbes that live in your large intestine do dozens of good things for you. They process indigestible fibers and help keep bowel function regular. They produce a number of vitamins, including B6, B12, and K2, and aid in the absorption of minerals such as iron, calcium, and magnesium. Equally important, they help fend off bad bacteria such as Salmonella and E. coli, which can cause diarrhea and, in extreme cases, severe anemia, kidney failure, and death.

          1. Wow. Thank you! Of all the things I’ve considered and read about, this makes the most sense. Could you please recommend a specific “human micro flora type of probiotic” brand and type that you’ve had success with, and trust? Would highly appreciate it.

            Also, some have reported anecdotally that fasting produces positive results in improving the macrobiome in regards to B12 status. Any thoughts? Thanks again for any suggestions on a probiotic brand/product.

            1. You’re welcome, I hope it helps to keep your B12 levels up. I recommend HMF Forte powder by Genestra, keep it refrigerated and take it with food.

              Fasting is a therapy that I have little experience with.

              According to Joel Fuhrman: “Americans eat 51% of their diet from processed foods and foods low in phytochemicals and antioxidants,” he says. “So you see a buildup of waste products in the cells — AGE, advanced glycation end products — that build up in cellular tissues and lead to atherosclerosis, aging, diabetes, nerve damage, and the deterioration of organs.”

              Perhaps it’s the buildup of the AGEs that affects the gut microbiome and by fasting our healthy gut flora is better able to support the production of B12 and other nutrients. Maybe Dr. Greger can point us to a study on this?

              Please let me know if things improve for you on the probiotic supplement.

          2. I tried to post a reply earlier but it didn’t show up as a posting. I’ll try again here.

            First of all, thanks so much for your reply. Do you have a specific brand of “human micro flora type of probiotic” you would recommend? I’d highly appreciate it, and of all the things that have been suggested to me, and that i’ve read online, your suggestion seems the most logical. Thanks.

    2. Something you might consider is which nutrients which are particularly high in whatever shellfish you are consuming. Oysters, for example, are high in zinc which is generally low in vegan diets. You could try adding a food source of zinc like pumpkin seeds and see if that has the same effect as the shellfish. While I haven’t heard of zinc being directly being associated with homocysteine levels it might work indirectly,

    3. thanks for this question, I am always researching about b12 because I also can’t take it in supplement form, as it causes me extreme anxiety (even though I normally do not suffer from anxiety at all). one time I almost had a full blown panic attack when I took it. It feels as though I just drank like 20 cups of coffee or something. It feels absolutelly horrible. But I can never find that much info about this, besides a few forum posts about other people feeling the same symptoms. Just wondering if these are the same kind of issues you have when taking it in supplement form? I dont have issues when I eat foods/drinks fortified with b12, but I think this might be because the amounts are much much smaller (always way less than 100% rda) than the supplement form. The supplement amounts of it are crazy high!!! I am technically a pescatarian so I do eat fish and shellfish, but only sometimes…I mostly eat vegetarian and vegan. But just because of the fact that I can’t supplement b12 and I certainly do not wanna become deficient, I wouldnt even consider going full on vegan. I’ve had my b12 tested last year and my levels were not deficient but not amazing either, I would say kind of borderline. I was even experiencing some symptoms that are associated with b12 deficiency…tingling in the legs, RLS, depression, insomnia, etc. My doctor said my blood work was considered normal, so she didnt think that this was related to b12. But since I have done so much research on this I felt like I was more informed about it than just some random GP who told me it was just stress and that I should try to relax! So I started eating more clams every week and all my symptoms dissapeared. I now try to eat clams once per week and I have been feeling great. I also eat some fortified cereals and nut milks sometimes, but I don’t want to have to be loading up on those every day just to get barely enough b12, when I can get wayyyy more of it from just a small serving of clams and eating them doesn’t cause me any weird symptoms. Anyway, I wish that I could just take it in supplement form without any of these weird symptoms, it would definitelly make things much easier and I could consider goin full vegan. Anyway, thanks for the article and thanks again for the question and discussion Elsie. It’s at least comforting to know there are others out there like me when it comes to b12.

      1. Hi Je!
        Just looking at your question…and was wondering if possibly it’s something added to the B12 supplement that’s causing your symptoms? Some B12 supplements contain added ingredients and colors…did you see this piece Dr. G. did about artificial food colorings and ADHD symptoms? Not that ADHD is the same as the anxiety symptoms the B12 supplement causes you, but it just occured to me that maybe there was a connection?

    4. It’s not a genetic issue, the B12 in supplements is trash, like all supplements. It’s not the same as real B12. Where does a gorilla get is b12? where does the giraffe get it’s b12? Where does an elephant get it’s b12? Why is it that the natural way all animals get b12 is hidden from the public? I’m not yet sure exactly which is our natrual way to get it, but I’m pretty sure it’s natrual river or stream water. Bacteria can only form in water, and that water can’t have high oxygen levels. You simply can’t get b12 from a place that has no water, it comes from water and nothing else. Mushrooms have b12 on them too, as long as they are not washed. – I am about to do an experiment, sense going and getting river water sounds like a pain, I’m going to try a few things: Rib moist dirt on my arm before I sunbake, than lick my arm after(this will kill all bacteria sense bacteria can’t survive outside of water, hopefully the b12 microbe is uneffected). This is also way to test if licking your arm can rise Vitamin D to high levels, Vitamin D washes away from water and can take 5 days to absorb into your skin, licking my be the ultimate way to go. ill also try using the sun to distill water at home than put some dirt in, mix and drink. ill try mud bathing as well, that might be enough to get b12. – In theory putting some dirt in distilled water will work, just use a bucket, place a glass in the middle to catch the water, put water in the bucket around the glass, food wrap/plastic wrap over the top of bucket and a little rock or weight in the middle over the glass.

      1. I agree! I am also very curious about how do other animals, as you have mentioned, get obtain their B12 level. Why do we tend to see meat, form cows, pigs etc, as the only source of this vitamin even though animals can not synthesise it themselves? I have been trying to find articles about the importance and real sources of the B12 vitamin, however I am failing miserably….

  2. I’ve been a total vegan for the past 15 years and for that time have eaten Nutritional Yeast (supplemented with B12) to compensate for the absence of animal products in my diet. Four months ago, on routine physical exam blood tests, I showed a sl. macrocytic anemia. My primary care ordered a B12 assay, and it was significantly low. Everything else is normal, and because of my age (77-yr old female) he is assuming that I have a reduced capacity to absorb B12 through the gut (decreased Intrinsic Factor etc.). I am now on sub-lingual daily B12, and will go back for another B12 in two months to see if it makes a difference. What surprised me was that I did not have any of the typical symptoms of a B12 deficiency, although it’s possible that my levels were not low enough for me to develop clinical symptoms.

    1. 6rtury: I’m glad you caught it in time – ie before you experienced symptoms. I’d say that you are doing pretty good. I hope the daily B12 makes a difference. If you are interested, please report back and let us know. I’ve been taking the B12 sublingual weekly. And I wonder if it makes enough of a difference. (Not that I’m low as far as I know. But I couldn’t get my previous doctor to do the test that Dr. Greger recommends – just the less reliable test, which showed normal. And my current doctor is blood test averse. (sigh). )

      Good luck to you.

          1. Not at all. And for a while I thought it was just me, so I considered keeping it going and just waiting till it worked, but I’ve since discovered folks who have horrible reactions to the injections. Who knows, maybe there are proteins/amino acids in the shellfish that my body depends on to create all these mechanisms/cycles/processes to occur in my body that are related to B12/folate/homocsyteine, ec., and that for some reason plant proteins are not as effectively utilized in me. Once again, it is very frustrating, but I am sure as heck not the only one who has claimed to wither/suffer when 100% vegan. I feel a bit lucky that I’ve been able to avoid beef, poultry, eggs, dairy. And I keep the shellfish minimal, not an everyday food.

            1. For a while I couldn’t decide whether to get injections or just take a sub-lingual. In the end I decided to compromise and get sub-lingual injections.

          2. I’ll add that a big part of my bringing this issue to light here is not just for my own well being, but for that of those who hope to become 100 percent vegan but who have not been able to due to this issue with B12 supplements. I think if this “riddle” can be solved, they’ll be that many more who are now willing/able to be vegan. It is obviously not the majority who are intolerant to B12 supplements, but I do find it interesting that most people I know who have had their B12 level tested have never had their homocysteine and MMA levels tested, and most doctors I’ve met with rarely test homocysteine and MMA to check B12 status.

              1. I’ve read over the nori B12 debate/studies. I’m not comfortable ingesting massive quantities of iodine (from the nori) in order to maintain healthy MMA, homocysteine, and B12 levels, yet experience has shown me that there’s merit to the effectiveness of raw nori, in regards to the B12 issue.

                1. Hi, actually, raw nori has relatively low levels of iodine, in relation to other sea vegetables, and particularly in contrast to kelp, and anyhow; plant based iodine is often lacking in our diet. Check for yourself :-)

                  1. Yeah, I am aware of that. But the amount of nori needed to maintain adequate levels of B12, MMA, and homocysteine, for me, would all of the sudden turn into high iodine intake. When I greatly exceed iodine intake from nori, I notice some benefit, but unless I do this the nori does not seem like a long term solution to the B12 issue.) Point being, I’m convinced that I’d have to take well over 1000 percent of RDA of iodine (to consume enough of the B12 in nori) to help me. Not gonna do that.

                    1. Yes, but that is a western standard. You would not intake more iodine than the average japanese citizen. Unless one consumes vast quantities of seaweed; you highly unlikely to have any problem with excessive bio-iodine intake. Anyhow, the active B12 content of raw korean nori is on par with some of the most excellent sources of animal based B12.

                      Furthermore, Chlorella is another option, but check its contents. And Hydrilla as I mentioned in my first post is the richest source of B12 ever discovered, although it remains unknown as to how much of that B12 is fully active.


                    2. I’d rather not debate the merits of excessive iodine intake. I’ve read over the data, and there are plenty of experts and doctors who have concluded that it is not safe to exceed the iodine level. I am aware of the Japanese intake of iodine. For me, and my health and body, it does not seem prudent to follow that path. And this is through direct experience. Excessive iodine intake has not been a good thing for me. But to each their own, whatever works for you and your body.

                    3. Firstly, I was not debating anything :-). It is a fact that the japanese intake more than 10 time the western recommended level of iodine, without issue, quite the contrary. A few communities by the sea, in Japan, do in fact intake excessive quantities of iodine, but they are including massive amounts of seaweeds and seafoods, far exceeding common Japanese intake levels, and even then, most members of such communities do not have any issues.
                      If you have certain thyroid disorders; significant iodine intake can be an issue, even when it is in taken in its bio form, via plant based foods.

                      Secondly, I provided you with several other options, instead of animal foods. And seafood likewise contain large quantities of iodine.


                    4. Yes, I didn’t think you were debating. I just thought it might head that way, so I mentioned it. Thanks for all your suggestions and info.

                    5. I have not. I see online that people are making claims that this has true B12 in it, but I have yet to see any credible research on this, and for now I will assume that if it contained true active B12 the sea buckthorn would be the biggest hit in the vegan community to date, and this berry has been around for a while. I know of no one in the vegan community that is relying on seabuckthorn berries for B12, and I think the only way I’d be comfortable gauging its B12 merit is to run MMA, homocysteine, B12 tests after a significant time of relying on just that for B12.

                      But not to say it is not legitimate B12. Just going with my gut for now. If you have credible scientific evidence to share with this community (Dr. Greger, most importantly), please post it here, as soon as possible. Otherwise, I think the berries just might be another “superfood” marketing product.

                    6. Yeah you could wait a couple of years for someone to do a randomised controlled trial, or you could just eat some sea-buckthorn berries and see if they do the trick. Or maybe even some black trumpet mushrooms. To some extent I think it’s distasteful to let other people do your guinea pigging for you. The trouble is that shellfish are one of the biggest causes of food poisoning, so if it was me I’d be doing everything I can to find a less riskier source of B12 and not being all “show me the evidence and then maybe I’ll think about it”.

                    7. Yeah, I hear yah on the shellfish concerns, but with B12, “show me the evidence” is of critical concern and importance. If there is one vitamin you don’t want to take a chance being deficient in, this is the one (so it seems).

                    8. All I know is we need to put our heads together and try to find you a less snotty source of B12. Because I think you’re putting yourself in serious danger here. In serious danger of basing your diet on something that looks like it belongs in a ruffled handkerchief if nothing else. My money is on the sea-buckthorn berries. Although probably not the more cultivated varieties. Why not give it a shot, because there really is no risk from giving it a try. Even if it’s inactive you’re not gonna suffer from nerve damage just from just a three/four week trial.

                    9. If you have a reputable source of sea buckthorn berries, please post it here. I’ll consider trying it out. Thanks.

                      Also, have you used seabuckthorn as your exclusive source of B12?

                    10. Have you tried sea buckthorn berries? Did they raise your B12? Did they lower your homocysteine reading on a blood test?

            1. I was disappointed that when I asked my doctor for a homocysteine test, he said, “there is nothing that can be done to lower the levels so there isn’t any need to do the test”. This doctor believes in preventative medicine, vegan diet and healthy lifestyle and drugs only when absolutely necessary.

            2. I am not as well informed on this subject as I would like but I have a general question. For people who want to be 100% vegan but realize the need for b12 supplement, from what source is/are the b12 supplements derived? I’m assuming there are vegan sources of this nutrient.

        1. elsie: Thanks for your post. I don’t know if I’ve had those tests or not. I do know I won’t get them from my current doctor.

          I’ll keep what you wrote in mind. I hope you are able to find an alternative. That is indeed very frustrating.

          1. Thea, If your doctor won’t order the test for you and you really want to know; order the test yourself from an online lab. Your insurance may not pay but you will know

                1. Oh cool. I might just do that.

                  I am guessing that some such companies are better than others in terms of quality of results. And maybe cost??? Does anyone have specific recommendations?


    2. Have you had your MMA serum level tested? How about your Homocysteine serum level? I’d suggest you test these as soon as possible. Please report back to us any results. Thanks!

    3. 6rtury,
      I stopped relying on nutritional yeast for B-12 some years ago esp from bulk bins. Red star makes nutritional yeast with and without B-12 supplementation. Twice I have discovered that bins labeled as nutritional yeast w B-12 were falsely labeled. I found this out by asking staff at MOMS and TPSS to show me the bag in the storeroom they were filling the bin with. Each time the box was labeled Red Star yeast without B-12. It is an easy mistake for any store to make and I wish that Red Star would only make one form of yeast, one that has B-12. I believe that B-12 tablets are the most accurate source, do not rely on nutritional yeast.

      1. David: This is a great tip. I only eat nut yeast for pleasure, but I would not have guessed that this could be problem in the bulk bins either. I would have previously referred people to nutritional yeast as an option without qualification. So, thanks again.

  3. Methyl- or cyano-?? I look for the methylcobalamin B12 as I’ve heard the cyanocobalamin B12 is significantly less effective. Cyano appears typically cheaper, if it isn’t doing what my body is needing, then it certainly isn’t worth it regardless of cheaper price. I don’t think Dr. G has addressed these two varieties that are commonly available.

  4. If I may add my “two cents” to the discussion, the bioavailability factor of the B12 vitamin taken is one of, if not, the KEY factor involved, which would mean organic sources, i.e., chemical-free foods and supplements rather than synthetics and pharmaceuticals. Also, for any one of the B vitamins to be utilized efficiently by the human body, the entire spectrum of B vitamins needs to be present/supplemented. At least that’s what I learned when I studied nutrition.

  5. Can you have TOO MUCH b12?
    On my last blood test, my b12 levels were actually above the “sufficient” level, despite being vegan

    1. Great question Simone. The standard CBC test for B12 is pretty much useless. B12 levels will always appear extremely elevated on that test if you are taking supplements with B12 in them. A more functional analysis would be MMA (methylmalonic acid) but even that is not always an accurate indication of B12 needs. I encourage my clients to take B12 for at least two months and look to symptoms to determine if their needs are being met. As a water soluble nutrient, the safety margins on B12 are very high.

  6. I wonder if any research has been done on meat fortification. The animals get supplemented (google for lifestock fortification) so my question would be: what would the b12, vitamin D levels etc. be for meat which wasn’t fortified/supplemented.

    1. nearly all meat is contaminated with feces which contains an abundance of b12, meat eaters feces consumption is what gives them their b12, its quite disgusting

        1. Han that’s the question that I wanna know the answer to as well. I wish I’d seen your post earlier because I just spent half an hour writing about the exact same thing.

  7. Dr Greger

    I don’t understand why you never mention the fact that most farm animals are given some form of cobalt and/or B12 supplement in order to prevent b12 deficiency. Aside from any other interesting questions this raises, it represents a massive indirect B12 supplement for the people who consume those animals, and to my knowledge this has never been adjusted for in any study comparing B12 status of vegans vs non-vegans.

    Not that this means vegans shouldn’t supplement with B12 of course. If anything, the fact that so many pasture-raised animals need some form of B12/cobalt supplement provides a strong case that humans should take b12 supplements as well. But what this also demonstrates is that:

    a) Having to take a supplement in this day and age doesn’t necessarily mean that this isn’t our natural diet, and

    b) Non-vegans are just as dependent on supplements as we are, if not much more so. The only reason they don’t notice it is because the animals they’re eating have already taken the supplement on their behalf. Notwithstanding the many non-vegans who do take b12 supplements directly, either via multivitamins or fortified foods or via their doctor as a result of medical necessity.

    1. In a debate with a carnist I often hear the argument that meat contains b12 and therefore we need to eat meat. And then I explain that animals are just like us and that they need b12 as well and they get injected with it, along with a whole lot of other stuff. And I explain that raising an animal in horrible conditions and stuffing it with essential vitamins and then slaughtering it is not a good excuse to eat meat if we can supplement ourselves.

      1. Right. And what’s especially interesting to me is that it’s not only factory-farmed / grain-fed animals who get supplemented. The use of cobalt supplementation is widespread in organic pasture-based systems and it’s main purpose is to prevent b12 deficiency. Farmers are spraying the pasture with cobalt sulphate solution or providing cobalt salt licks or even administering it via oral drenching. And this is before we even get to all the other mineral supplements they give to the animals (copper, zinc, selenium, iodine etc). This is a massive indirect supplement for the people eating those animals. All the while they’re pointing their finger at us saying our diet isn’t natural because we’re taking supplements.

      2. I for one am extremely appreciative animal plight is NOT part of, it tends to keep discussions cerebral instead of emotionally fueled. There is nothing to be gained from it and tends to end in who has better morals squabbles that add absolutely nothing of value.

        1. Even though I am very concerned about the lives of animals I could present my request in another way:

          Meat is being sold with the argument that it is the only natural source of specific vitamins. Which is patently untrue since the animals are supplemented and don’t get their vitamins from natural sources. Also meat has a lot of very dangerous health risks.


          1. There is just a spectacular range of variables and all of them I would supposedly have to support if I were to agree with you here, and I just cannot do that.
            Grossly tainted meat from the most abused animal imaginable sold as free range, could still safe a life under the right conditions you know :) ^^

              1. That’s fine, I’m secure in the fact that there is nothing man does that natural selection and evolution doesn’t do a hundred fold worse every day. Even from that point of view it makes it a marginal, even I dare say luxury issue, at best. I’m leaving this discussion now the chief offender in just the type of discussion I just renounced, the irony! Arrrrg!

                1. Han, don’t let this guy bait you like this. He’s just trying to distract people from your very hot original question about the B12/cobalt supplements given to farm animals, IMO. .

            1. However the current available statistics show quite a different story. The wealthiest nations are those exploiting the animals by any means the most not the poorest.

              In UK, for instance, the cost of living is ridiculously low (albeit people keep complaining all the time while the waste their money in useless consumerism) and the level of exploitation is astonishingly high.

              Anyhow, quite off topic here.

              Take care,

  8. I have a question for Dr. Greger that is not necessarily related to the topic of vitamin B12 in the vegan diet. I thought of this question just a few hours ago. Over the weekend, I learned that 75% of healthcare spending in the United States goes towards treating chronic diseases. What percentage of healthcare spending goes towards the prevention of such chronic diseases? It would be better if the medical prevention could prevent these chronic diseases from taking root in patients, but they insist on treating and treating patients, which drives up costs. How does the amount of money that the United States spends on the treatment of chronic diseases compare to other healthcare systems around the world? Are there countries whose healthcare systems manage this chronic disease problem better than ours does? Likewise, are there countries whose healthcare systems invest more healthcare dollars into prevention? If you have the answers to these questions, then I would like to learn from you. Preventive medicine has captured my attention. I am 24 years old and would like to matriculate into medical school in the next year.

    1. Can a moderator please remove this post. It has absolutely sex all to do with B12 and was probably posted just to distract people from the issue at hand.

        1. Well, if you think Jim’s question is a great question, then I’d hate to see what you think is a not so great question. Either way I think it’s a crying shame that neither Dr Greger or anyone from the NF team has responded to what is arguably a more pertinent question about the cobalt supplements given to pasture-raised farm animals.

          1. Hi Theodore, Dr. Greger and the rest of us at are happy that the site can be a platform for answering user questions related to healthcare and nutrition, whether or not they are directly related to the video or blog post under which they are posted. We would appreciate your tolerance of this policy. Thanks for your concern! As for the cobalt question, I’m certainly intrigued by this question as well, and hope Dr. Greger will consider making a video on it. If I hear anything, I’ll get back to you. Thanks! :)

    2. Jim, I don’t have any answers for you in regards to how much money we spend on preventative care or how various countries handle it. However, this website/NutrtionFacts has a great deal of information on how a healthy Whole Food Plant Based diet can prevent a wide range of diseases/conditions. So, I think you are in the right place to learn about how to do this. I believe in the United States, such an approach is called “lifestyle medicine”, which includes other factors in addition to diet, such as exercise.

      I think the world is desperate for more lifestyle medicine doctors. It is currently an uphill battle to get educated as such, but if you can manage it for your career, that would be really awesome. I hope you are able to do that. Good luck!

      1. Jim, prevention is the only medicine according to most doctors. Most medicines prescribed today do not work immediately, well, have poor side effects, require lifestyle modification, and need to be taken forever, meaning that they are probably not treatments. Nuts, beans, green tea, dark chocolate, berries, fresh fruit, and vegetables can prevent many illnesses.

        I have made a table of preventative health advice. Almost any food here can have almost any of the other effects. There are fibonachi foods in each category (1,1,2,3,5,8,13,21). These foods have cascading effects for your health.

        A light beer a day and a low dose aspirin virtually eliminate heart disease (probiotics)
        A grape fruit a day and a vegetarian diet could add more than ten years to your life (orange juice, cherries)
        Ten cups of green tea a day and cutting back on smoking would almost guarantee you live to 85 (Lemonade a day, green pepper)
        Six cups of coffee a day and a serving of beans would dramatically reduce your risk of colon cancer, a
        surprising killer (black raspberries, sunflower seeds. strawberries, billberries)
        Moderate exercise and a diet low in saturated fats can improve your mood dramatically (meditating, yellow squash, pistachios)
        Eating tomatoes and soy twice a week can restrict your risk of getting most cancers (brocalli, watermelon, beets, garlic, flax seeds, seaweed)
        A diet rich in blueberries and whole grain can restrict your ability to get a stroke or dementia (grapes or grape juice)
        Eating an Once of nuts a day and eating a cruciferous vegetable with olive oil and vinegar and tumeric
        once a week can help your heart in a diabetes future and manage a heart disease later in life. (miso soup)
        Eating two servings of dark chocolate a week and getting five minutes of exercsie a day can
        eliminate your need for heart surgery and reduce your risk of heart disease death by half. (lentils)
        Two servings of herb tea a day and sweet potatoes can make you seem five years younger (clove, tumeric, ginger, cranberry juice)
        Drinking 8 glasses of water a day, especially before meals and a banana a day before meals can damage your ability to get metabolic X syndrome and make you lose weight (pumpkins, apples, hibiscus tea, brazil nuts, macademia nuts,

        Thank you, Matthew

        1. can some one tell me if coq10 is good for energy levels and can
          anyone have it also which are the best natural and organic brands out
          there one can fully trust which is non GMO and truly organic for health
          like b12 suppliment and coq 10, how many practioners are here from dr
          michaels side are there , if some one could mail me at
 would really appreciate it

  9. What are recommendations for children on plant-based diets in various life stages? How much B12 should be supplemented, how often and in what forms (through mother’s breastmilk, sprays, crushed pills mixed with food, etc.)? What supplements besides B12 require special attention (and possibly supplementation) in children?

        1. Theodore: PCRM is also a good resource. But from what I have personally seen and spoken to others about, so is VRG. Thanks for adding yet another resource.

            1. Toxins: Great page/article. Thanks for the link. PCRM did a great job.

              But dang. “Really DGAC? Can’t you show some greater integrity?” Argh.

  10. Important message but flawed title, “The vitamin everyone on a plant-based diet needs.” Of course, the vitamin we all need is all of them. There is a tendency for people to use the term “vitamin” to mean “vitamin supplement”, as in “Did you take your vitamins today?” But not typically on

  11. I am printing out this information and giving it to my parents who have recently switched to a WFPB diet after reading Whole and The China Study. Two excellent books, but they do not speak of this urgent topic. I have mentioned it to them before, but they seem to think B12 is not a major issue. My parents are avid readers but don’t really go online all that much and don’t watch your videos. I am hoping your book (in 2015?) will help them to complete the picture of what a healthful diet should entail. I know you are swamped, but do we have any news on a possible publication date? Thank you. PS – A nice feature for your blog posts would be a ‘print this page’ button, so that I don’t have to print out all of the comment section. Just a suggestion. Forever grateful, Barbara.

  12. Since our livers store B12, what is wrong with eating a cup of clams (the richest source of B12, according to Nutritiondata) once a month…and foregoing all other animal products–assuming one is not an absolutist? I have a natural aversion to popping pills and would rather get my nutrition in food whenever possible. Seems like one could then be 99% vegan and get the best of both worlds.

      1. Per Nutritiondata, 100 grams of cooked clams contains about 100 mcg of B12–which it says provides 1,648% of the RDA–about 16 1/2 days worth. Don’t know where you’re getting the 2.5-5 mg/week figure from. That would be about 500 mcg/day, or nearly 100 times the new RDA for B12 (the old RDA was lower–only about 2.5 mcg/day).

        1. Please watch the video to have an understanding of how much b12 you would need. The RDA % has little value for b12 due to absorption, use, etc. The numbers I provided are based on this knowledge

          1. OK, I watched the video (Cheapest Way to Get B12), and understand the absorption problem. We can only absorb about 1.5 mcg + 1% of the remainder. So if one ate 300 grams of clams, which contain 300 mcg of B12, he/she would only absorb 1.5 + 3 = 4.5 mcg, which is just a daily dose under the new guidelines. Since you don’t recommend that we eat 300 grams of clams/day because of the cholesterol involved (200 mg–about as much as in a small egg), we are left with either taking supplements or fortified foods. However, the math would indicate that all omnivores are deficient in B12 unless they eat foods high in B12 at least twice a day. Someone eating 100 grams of sirloin steak every meal would only get 4.5 You could also get by with eating 50 grams of salmon three times/day. So by this formula, you are really indicating that the only people who are getting enough B12 through their diets are those who eat 300 grams/day of clams, or a vastly higher amount of the richest sources of B12, such as oysters and organ meats–chiefly liver, or those who ensure they get 1.5 mcg every meal–based on three meals/day. Since this is rather unlikely, I take the liberty of doubting your formula, or suspecting that it only applies to those who take artificial supplements and fortified B12 foods. It seems logical that one would absorb more B12 from food on a percentage basis than from pills–more than 1.5 mcg plus
            1%. Still, by your own formula, one could eat as little as 2 grams of clams three times a day to get the RDA. That would be a minuscule dose of cholesterol. You could also get by with taking 50 grams twice a day. Thanks for alerting me to this problem–or reminding me of Dr. Greger’s video. I had no idea we absorbed so little B12 from a single meal.

            1. Jason, I am not Dr. Greger , so the “your” in this is misdirected. Lets clarify. All you would need to do to get b12 daily as an ominivore is to consume anything that had 1.5 mcg of b12, 3 times a day, or added up to 4.5 at the end of the day. This is not that hard considering that cereals and refined grains are often fortified and many animal foods contain b12 in adequate amounts.


              The formula is based on quite a but of studies so its applicability is high. The absorption rate is based on physiological factors so to assume this “It seems logical that one would absorb more B12 from food on a percentage basis than from pills–more than 1.5 mcg plus” is inaccurate.

              Also, I would question consuming any seafood, even a little once in a while, since seafood at this point in history is the most contaminated food product one can eat in general. It takes decades for our bodies to rid itself of pollutants that come from seafood.


              Supplements are cheap, safe and easy. I personally do not understand your resistance to taking a 2,500- 5,000 mcg sub lingual tablet once a week if it spares you any potential harms from consuming animal products.

              1. I appreciate your taking the time to write well researched and crafted responses. I did a little reading of my own and agree that my assumption that B12 is more readily available from food than pills is unwarranted. If we need 4.5 mcg/day (I say, ‘if’ because the British, for example, are still claiming that we only need one third this amount), the logical thing to do would be to get 1.5 mcg at every meal (assuming three meals/day), and if they were clams or oysters, we’re talking just 2-4 each meal–which would involve a negligible amt. of cholesterol. I looked at the one video which featured ‘clams’ which Dr. Greger has made, and they came out looking pretty good in comparison with beef, chicken, and cheese in regards to pollution. I agree that there is bound to be more pollution in shellfish than in some other animal products, but we are talking about such limited quantities–essentially 5 grams or less each meal, or less than 15 grams/day. I think clams and oysters would also violate the esthetic criteria of veganism less (e.g., don’t eat anything which has a face or a mother) than eating beef, pork, chicken, or even fish, while dairy foods and eggs have too much saturated fat and/or cholesterol for the amts. needed. If I decide to take a supplement, I’d probably opt for taking one a day–which I suppose would be 250 mcg. But I’d rather take even smaller doses three times per day (don’t know if it comes in smaller doses). Don’t like the idea of taking any more of a nutrient in pill form than I need.

                1. The good thing about vitamin b12 supplements is that it is water soluble, so there is no risk of toxicity if you do decide to do so. The idea of supplementation may not necessarily be appealing, but it serves the same physiological function as food sourced b12 and has no harmful side effects. For me, I see no risk in doing so. If you haven’t already seen it, the vitamin D video series may also interest you.


                  This video is also the first of a series like the B!2 series.

                  1. Again, I appreciate the responses. I think for me taking a pill–something made in a lab– is a greater step than eating a small amt. of animal products, particularly ones I cook from scratch. Just seems more natural. I agree, the downside is limited since there’s no tolerable upper limit, But reading the page on B12 from the Linus Pauling Institute, it seems that the 1% absorption (from Passive Diffusion) only applies if the other absorption pathways are shut down–because the stomach doesn’t make enough Intrinsic Factor, or the pancreas or small intestine aren’t working properly. I agree that the likelihood of all these mechanisms working flawlessly diminishes as we get over 50 years old, and there may be other factors like not having enough calcium or Vit.C, or perhaps inherited Pernicious Anemia. All of these are potential limiting factors which can certainly lessen the absorption of B12. But how likely is it that the absorption totally shuts down and goes to zero? I think chances are we’d still have some absorption apart from Passive Diffusion, and thus we’d likely get much more than 1%– though I haven’t been able to determine quite how much (the percentage). Another (vegan) website poo-poohed the notion that B12 deficiency is widespread in the vegan community, else it would have been written up, if not sensationalized in the medical press. So at least classic B12 deficiciency is rare. Are all of these vegans–the ones not deficient– taking B12 supplements? I doubt it. I’ve been vegan off and on for many years without taking vitamins or even eating fortified breakfast cereal (it’s pretty much been otameal my entire adult life). The LPI said that studies have shown that while giving B12 to those with high homocystein levels often brings them down, this does not translate to lower CVD or total mortality deaths. (It has shown significantly lower deaths from stroke, however). So the key is to not get hyperhomocysteinemia in the first place, I guess.

                    I think I’ve already seen the video on Vit. D. Since I live in the tropics and get outside most days for a couple hours in the late morning, I probably am getting enough Vit. D from sun. My arms, face, and lower legs are tanned, even if the rest of my body hasn’t been exposed.

                    1. We absorb 1.5 mcg plus 1% diffusion, im not sure what other absorption there is or what your speaking of. Also, I would comment that is not a vegan website but a science based website. Other “vegan” websites that do not advocate b12 simply are ill informed. Vitamin b12 deficiency can take a decade or 2 to manifest due to our bodies efficient recycling mechanisms. Once depleted, it can be difficult to bring back to normal levels and is dangerous. Please see here.




                      I understand what you mean when you say “I think for me taking a pill–something made in a lab– is a greater step than eating a small amt. of animal products”, but for me, the line of logic does not make sense when the supplement is completely safe and the animal product is not.

                      As a last comment, if you have seen the entirety of the Vit. D series, you would find out that getting sun on the arms, legs and head does not result in adequate vit. d absorption. Most people are Vit. D deficient, even those that get lots of sun exposure.

                    2. OK, I’ll assume that that’s the formula: 1.5 + 1%. In that case, I’d rather take 1.5 mcg three times a day than a megadose once a week, or even 250 mcg once a day. Shouldn’t be too hard to get 1.5 mcg in my morning soymilk and take a pill containing 2 mcg for both lunch and supper.

                      Re: Vit. D, I went shopping for vitamins today and couldn’t find pills with more than 400 IU (only the multivitamin pill had 400 IU, and the ones with only Vit D and Calcium all had 200 IU–or even less). I know Dr. Greger has researched this issue, but find it very hard to accept that we need to be taking FIVE TIMES the RDA. That seems excessive, especially in light of the fact that we get some Vit D from sun exposure. In fact, the reason I wasn’t concerned about Vit. D supplementation was because I was relying on what Dr. Greger wrote:

                      Below approximately 30° latitude (south of Los Angeles/Dallas/Atlanta/Cairo)

                      15-30 minutes of midday sun (15 for those with lighter skin; 30 for those with darker skin)

                      or 2,000 IU supplemental vitamin D daily


                      I actually reside below 20° latitude, so I think I should be getting plenty of D naturally. Also, I eat LOADS of mushrooms every day.

                      Still, to be on the safe side, I decided to buy the Calcium-D formulation (can’t get Vit. D here by itself) and take 200 IU/day. That just leaves Omega-3 as a potential issue, and I take 2 heaping tbsp. of flax seed/day, and sometimes eat walnuts. I assume that getting ALA is sufficient, and don’t need the animal source Omega-3’s.

                    3. I notice that Dr. McDougall says that vitamin D pills should be a last resort, the first choice should be safe sun exposure, and he even says that the second choice, even before popping a vitamin D pill, should be safe sun-bed/sun-lamp exposure. I find this very interesting. And at some point I’ll bring it up with Dr. G, but hearing it from our good buddy McDougall that a vitamin D supplement should be one’s last choice in order to get adequate vitamin D intake really got me thinking. Thoughts?

                    4. I also am aware of Dr. McDougalls recommendations. I don’t know whether or not he has seen the evidence Dr. G has shared, as it is quite compelling.

                    5. Yes, Dr. G has put out some compelling evidence, but I do find it revealing that my immune system seems to be suppressed when I take vitamin D by pill, but when I get my vitamin D from the sun things are fine. I can’t help but wonder if the sunshine’s vitamin D is more “complete”, “real”, “natural”, etc., and if the “pill” version of vitamin D has something in it that is, while fine and beneficial in some regards (the evidence seems to show this), in some untold way it might be unnatural for the human body. Just my thoughts here, but I know of others who have had vitamin D pills make them “feel” great and get their health back in certain regards, but at the expense of suppression of their immune system.

                    6. Sun light exposure is beneficial in other ways besides Vitamin D… such as improving arterial function via the liberation of stored nitrates, etc. into our arteries. You just have to keep in mind that the track record for isolated nutrients especially fat soluble ones such as Vitamin A and E is not very good. That said there are certain circumstances where Vit D is appropriate. I’m sure Dr. McDougall would agree with that.

      2. I have not found this to be true (having to eat a massive quantity of clams). I have been able in the past to raise my B12 level considerable amount by eating some shellfish. Normal portions several times per week. I’d rather not have to resort to shellfish (would rather be vegan) but I can not seem to find any supplement forms of B12 that do not wreak havoc within my body. (have tried all the brands, formulations, non-additives, etc. of B12. No luck.)

  13. I still did not see anyone address my question about the source of vitamin B12 supplements. I just want to know what are the sources used to make the B12 supplements. Obviously to be vegan it would have to have a vegan capsule or caplet form. And the source of the vitamin B 12? I see the idea of oysters as a source of being tossed around but those are still living organisms and I am wondering if there are other sources? The only source I have seen is in nutritional yeast. I don’t know if some people have a problem digesting that or absorbing the vitamin B 12 from that. Reading the labels on vitamin B12 supplements they don’t really disclose the source

    1. Many different sources. Cyanocobolamin appears to be best type of B12. Red Star nutritional yeast does have B12. Careful about relying on fortified foods for all of your B12 needs, as you mentioned companies don’t do the best job labeling. Check out Dr. Greger’s Optimal Nutrition Recommendations for B12, if interested in more information.

      Thanks for your comments, let me know if this helps?

      1. How did you determine that cyanocobalamin is the best source of B12? I can not find any science saying one way or another. Thank you for clarity on this.

  14. I’m sorry, I know this contributes absolutely zero to this conversation and probably will get virtual tomatoes thrown at me (or worse!) but having raised 2 boys in a major city and now being grandmother to more boys, I guess the 12 year old boy in me is ever alert. I was very present and concerned in this serious discussion that absolutely concerns me because I am a WFPB vegan, and do not take the topic lightly. However, this was short-circuited the minute that 12 year old boy in my brain noticed the abbreviation : MTHFR. I KNOW it’s a leap, and I know it’s ridiculous and I know it’s totally inappropriate, so why did I feel the need to comment? Maybe psychiatric drugs aren’t such a bad idea after all? LOL!

  15. I know B12 does not come from animals per se, but from organisms in the soil. I’ve also heard of some controversy surrounding commercial probiotics made from soil-borne organisms, but it was a while back and can’t remember exactly what the issue was. In fact, I actually recall reading a way to culture soil to create your own probiotics, with a disclaimer that it could be dangerous…so I dropped the idea, but… Now I want to know why, because I have since really gotten into fermentation and natural probiotics and want to at least understand the mechanisms involved and learn if they possibly have anything to do with B12 supply. I believe the theory goes before our rigid hygiene, we obtained B12 directly from dirty produce? Not that I relish the idea of eating dirt, but I wonder just how much would have to be consumed to be a “therapeutic” amount, just for the sake of curiosity? I am all for trying to stay as close to nature as possible, but safety is a key issue since better health is the desired outcome! If anyone knows of any studies in this area and can direct me to any info, I would certainly be grateful! TIA!

  16. Hello, what is a clean form of vitamin B12 supplement?

    Most B12 supplements are full of preservatives and artificial additives. Can anyone recommend a very simple clean form of B12 supplement.

  17. Can your body only absorb so much B12 at a time? I know Dr. Greger recommends at least 2,500 mcg (µg) a week. Can your body only absorb so much B12 at a time? So would it be best to take 1,000 mcg at a time like 3x per week.

    1. Hi Derrek. I am uncertain of exact absorption values. It is safe to say your body can only absorb so much (you certainly cannot absorb all 2500 ug (micrograms) at once). There is no known Upper Limit, so taking more will not affect you negatively. I think either way the amounts you listed are fine. Check out Dr. Greger’s Optimal Nutrition Recommendations for B12. He list both of those intakes you described as options.

  18. The essence of your strategy is to eat what Mr Darwin’s process caused us to evolve to eat. So far so good…
    The $64,000 question: if that is a pure whole-food, plant-based diet, what did our ancestors eat to get their intake of Vit B12, your recommended diet does not supply?
    Not trying to be a Clever Dick, but they must have got it from somewhere if theirs was the ‘perfect’ diet versus the environment they adapted to.

    1. Hey Dan,

      Thanks for reporting your question. This comes up a lot, “is a vegan diet ‘natural’ and if so why do we need a b12 supplement?” I don’t’ have an exact answer and I would love more help from our members! A few things come to my mind: 1) What is even considered ‘natural’ these days? I feel we are very disconnected as humans. We don’t know where are food comes from, we seldom grow are own food or even experience being outdoors. Look at the problem with Vitamin D? Experts cannot agree on a preferred value. Also, take into consideration we as a country supplement and fortify our foods (i.e. iron and folic acid in grains, iodine in salt, etc.) There is some thought that humans were able to obtain B12 more readily from the soil while working in the soil, planting crops, and being outside in nature. I am skeptical about that theory and would never tell someone to obtain B12 from dirt. Also, what about water? There is some thought that our water supply used to have B12 and beneficial bacteria, however, we quickly learned of the harmful bacteria/parasites in water supply (think cholera) and now we use treatments to purify our water supply. From Dr. Greger “Our herbivore primate cousins get all they need ingesting bugs, dirt, and feces, and we may once have gotten all we needed by drinking out of mountain streams or well water. But now we chlorinate our water supply to kill off any bugs. So we don’t get a lot of B12 in our water anymore, but we don’t get a lot of cholera either—that’s a good thing!”

      There are 41 videos on this website that discuss B12. I am certain there is more about this important question. Let’s keep the conversation rolling!

      Lastly, it may be important to note it is not just vegans who need to supplement B12. Everyone over 50 years old is recommended to supplement B12, according to the Institute of Medicine – National Academy of Sciences.

      Thanks Dan!

      1. Hi, I’m not saying IS it natural, rather WAS it natural for those from whom we evolved. My instinct is that Michael has probably come up with the answer and that source for modern day vegans has probably been eliminated by social evolution and modern sanitation. I’ll stick with the supplements…

          1. Hi Joseph

            You may be interested to know that, since the 1930’s, numerous herbivorous species started coming down with B12 deficiency, even when eating their natural diet. Grass-fed sheep are probably the best example of that. Furthermore, numerous herbivorous species (eg fruitbats) start to suffer from B12 deficiency when taken into captivity and fed cultivated versions of the foods they would normally eat in the wild. All evidence points to mineral deficiencies in the soil. Hence cobalt supplements correct B12 deficiency in ruminant animals, and nickel supplements correct B12 deficiency in pigs (monogastric).

            No study comparing B12 levels of vegans vs. meat-eaters has ever taken into account mineral levels in the soil from which the vegans’ food originated. Nor did any study adjust for the fact that the meat-eaters were getting a massive indirect supplement in the form of the cobalt (and/or pre-formed B12) supplements that had been fed to the animals they were eating. Nor did any study adjust for the consumption of B12-fortified foods (eg breakfast cereals) by the meat-eaters. Furthermore, very few of the studies adjusted for multi-vitamin use amongst the meat-eaters.

            I find it extremely odd that even after having posted this information several times on this site and also having written to Dr Greger privately about it, he still does not mention it in any of his videos, articles or public interviews and apparently does not even share it with his colleagues. All I can think is that there is some kind of flaw in this information that he’s just too polite to point out to me.

            Kind regards.

            1. Thanks, Theodore! This is interesting information. I am not sure how the conversation with Dr. Greger went in the past, but please note he does listen to those who visit the site and really loves when he can read research to back up claims. If you some across any studies on soil and B12 let us know!

              1. Thanks Joseph. But just to confirm, are you saying that Dr Greger has been unable to find any research that backs up my “claims” ? If that’s the case I would be extremely surprised. Especially as he has a whole team of researchers at his disposal and much of what I’ve said can be corroborated by a 5 minute search on google. Nevertheless, I’ll be happy to provide studies where applicable. Just so I don’t waste any time though, perhaps you could let me know which “claims” he doesn’t think are supported by evidence. Apologies if I’ve misunderstood you.

                1. Dr. Greger “is” the researcher on this site. We have many volunteers and myself to help look-up studies and answer questions, but he does not have a team of researchers at his disposal. I am sure he’d love that though! Forgive the confusion, I just meant it’s easier to share studies you feel are valid and we’ll check with him to see if our information needs updating. I see you posted some studies thanks so much, give me some time to review and we’ll get back to you.

                  1. Joseph and Thea, many thanks for your feedback. I really appreciate it.

                    Joseph, I realise now that we were talking at cross purposes earlier. I fully acknowledge that any theories about the cause(s) of B12 deficiency in vegans are nothing more than conjecture at this point in time. I do believe that soil mineral levels play a crucial role in this conundrum of conundrums and did allude to that earlier, but it was only as an afterthought to my main points, which can be summarised as follows:

                    ● Numerous herbivorous animals are at risk of B12 deficiency in this day and age, even when eating their natural diet.

                    ● Said animals need to be given some form of supplement to prevent or correct that deficiency.

                    ● The cobalt (and/or pre-formed B12) supplements given to those animals constitute a massive indirect supplement for the people who eat those animals. As do all the sodium, potassium, calcium, phosphorus, magnesium, sulphur, iron, iodine, copper, manganese, zinc, molybdenum and selenium supplements also given to those animals.

                    ● The supplementation of those animals provides irrefutable evidence that the need to take supplements in this day and age doesn’t necessarily mean that the diet we’re eating isn’t our natural diet.

                    ● As well as eating supplemented animals, over half the American population consume (B12-containing) multivitamins, fortified breakfast cereals and pre-formed B12 supplements directly.

                    ● According to at least one study, even with all the supplemented animals, multivitamins, fortified breakfast cereal and pre-formed B12 supplements consumed by meat/dairy/egg-eaters, around 40% of them still have an inadequate B12 status.

                    ● Any article that talks about the (current apparent) need for vegans to take B12 supplements without mentioning any of the above facts is going to create (or at least maintain) a huge imbalance in the public’s perception about the naturalness of a vegan diet vs the naturalness of an omnivorous diet.

                    As I say, the above holds true regardless of whether supplemental minerals are found to resolve B12 deficiency in humans. But seeing as we’re on that subject, I might as well mention that I couldn’t tell from Dr Greger’s comment (communicated by you) whether there have been studies that tested the mineral supplements and found them to be ineffective or whether there simply haven’t been any studies
                    examining this question at all. Perhaps you could confirm one way or the other. If it’s the former, I would be very interested to know which minerals they tested and whether they made any adjustments for known B12 antagonists (such as nitrous oxide or antibiotics etc). Ideally they would test a wide variety of minerals because it would be presumptious to assume that the minerals responsible for B12 deficiency in ruminant animals (or even monogastric animals) would be the same minerals responsible for B12 deficiency in humans, if indeed mineral deficiencies play a part at all. Even amongst ruminant animals, different minerals seem to have differing ranges of importance. You may have noticed from the first article I linked to that the symptoms of copper deficiency in cows are eerily similar to those of B12 deficiency in humans.

                    Either way it wouldn’t necessarily change my view that soil mineral levels (whether it be cobalt, nickel, copper, iodine or some other mineral) are at the heart of the human B12 mystery. Because even if mineral supplements had been shown to be ineffective, it wouldn’t rule out the possibility that those same minerals might have a beneficial effect on human B12 status when abundant in the soil and taken up naturally by plants growing in that soil and then consumed by humans as part of the resulting whole plant-based foods.

                  2. Joseph, perhaps my point can be illustrated further by turning the OP’s question on it’s head and asking:
                    “Where is the evidence that humans living in a sanitised environment can maintain adequate B12 status by consuming un-supplemented animals (or their milk or eggs) ?”
                    Ideally such evidence would involve testing said animal products to see if they can lower MMA scores, but at this point I guess any evidence would be interesting to look at.

              2. Here are a few references to get things started:


                Again it would be useful to know which of my points Dr Greger feels are unsupported, so that I can concentrate on providing references for those specific areas. If you take nothing else away from this, let it be that people eating omnivorous diets are, for the most part, eating cobalt-supplemented animals (or in the case of factory-farmed animals, pre-formed b12-supplemented animals), so for them to question the naturalness of a total plant-based diet because of its current apparent dependence on b12 supplements, is somewhat hypocritical.

                1. Theodore: Thank you for the end of this last post, re: “If you take nothing else away from this…” It seems obvious after reading what you wrote, but I had been wondering previously what your point was. Now I get what you are saying/why you are making this point. Very interesting. Thanks.

                2. You may be onto something! From what I see these are bat and pig studies. Maybe you are right that human studies need to be conducted when you mentioned “No study comparing B12 levels of vegans vs. meat-eaters has ever taken into account mineral levels in the soil from which the vegans’ food originated. ” Perhaps that is why he is not commenting and when/if these studies are conducted on humans I am sure he’ll report. Thankfully you provided some links and information for site users here and that alone is very helpful.

  19. I am a bit confused about the reference to ‘one study’, which was actually also from China. You say that the their results showed that “vegetarians whose B12 levels were really hurting found that they had even thicker, more dysfunctional arteries than omnivores”. However the study does not mention the vitamin B12 at all, moreover it states that “Vegetarians also had […] thinner carotid IMT than the omnivores did”. That would mean that the vegetarians on which the experiment was carried on did not show thicker arteries, it was the opposite. Please excuse me if I am misunderstanding something, and I would be happy to clarify this part as well.

  20. One question I’ve always had is, if a WFPB diet is the healthiest way to eat then why is B12 not found in healthy amounts in plant food? This is a vitamin that humans need and if it’s missing than how can this be the best diet? I get this question all the time from non plant based eaters and I have no answer for them. It is a valid question. Any thoughts?
    Thank you!

    1. I just now read some of the questions and responses concerning the question I asked. I can see that there is really not a definitive answer. Some thoughts and theories but nothing concrete. I will continue to look for answers and respond ‘I don’t know’ to people who ask why B12 is missing in a WFPB diet.

    2. Hi Elizabeth,

      I am a volunteer for Dr. Greger. Thank you for your question. This is quite a popular question, and certainly a legitimate one. Let me try my best to explain.

      Vitamin B12 is made by bacteria. In animals like pigs, chickens, and cows, it concentrates in the animals’ tissues from their diet. Their diet, when not eating the processed junk that is fortified with vitamin B12, is comprised of grass, which is covered in bacteria. This bacteria produces vitamin B12, and through eating grass, they get ample amounts of vitamin B12. Humans however, thoroughly wash their produce before eating, removing the bacteria as well as the vitamin B12 that may have been produced by that bacteria on the food.

      In essence, hundreds and even thousands of years ago, we likely didn’t wash our produce like we do now. Maybe we’d brush off the excess dirt, but it left enough bacteria to provide for our vitamin B12 needs. Therefore, it is the extreme cleanliness of the modern human diet that leaves an unfulfilled vitamin B12 requirement.

      I hope this helps answer your question.

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