Increased B12 Needs for Adults 65 Years and Older

In the past, I have not had a separate vitamin B12 recommendation for adults 65 years and older. In January, I reviewed a study from the UK suggesting that 500 µg per day might be necessary (see Cyanocobalamin in People 65+). Since then, I took some more time to research the subject and have concluded that I should be recommending 500 – 1,000 µg per day for adults 65 and older.

I updated my B12 recommendation charts and have reproduced below a section I’ve added to, Adults Over 65 Years.

Note that I no longer have a twice daily or twice weekly recommendation for adults 65 years and older. I don’t believe there is enough information to determine either recommendation. Also note that these recommendations would hold for omnivores as well as vegans since all these studies were done on omnivores.

Adults Over 65 Years

Summary: Based on the studies below, it appears that 500 – 1,000 µg per day of cyanocobalamin is the ideal amount for people over 65 years of age to take in a daily dose.

There have been at least four relevant studies for how much vitamin B12 people over 65 years need, based on a once daily supplement. To my knowledge all of these supplements were cyanocobalamin.

A 2005 clinical trial from the Netherlands found that among people aged 70-94, who had vitamin B12 deficiency but were otherwise healthy, 16 weeks of 500 µg/day of cyanocobalamin was required to get MMA levels in the healthy range. Other doses tested were 2.5, 100, 250, and 1,000 µg (16).

A 2002 observational study from Canada of 242 people aged 70-94 without vitamin B12 deficiency found that those taking a daily supplement had significantly lower MMA levels (173 vs. 188 µmol/l; p = .042). However, there were many even in the daily supplement group who had elevated MMA levels. The range of supplements was from 2.6-37.5 µg/day with intakes being spread out about evenly over the range (17).

In a 2013 clinical trail from the UK in 100 people aged 65-86 with poor B12 status, 500 µg/day of cyanocobalamin was required to normalize MMA levels in 75-85% of the participants over 8 weeks. 500 µg was significantly better than 10 or 100 µg (18).

In a 2002 study from Seattle on 23 people 65 years and older with B12 deficiency but otherwise healthy, 1,000 µg of B12 was required to get the average MMA level into the normal range, as compared to 10 and 100 µg. This study was continuous in that first they put everyone on 10 µg for 6 weeks (moved average MMA from 581 to 400 nmol/l), then 100 µg for 6 weeks (moved average MMA from 400 to 380 nmol/l), and then 1,000 µg for 6 weeks (moved average MMA from 380 to 200 nmol/l). The final 6 weeks resulted in a big drop after the 2nd six weeks resulted in only a small drop (19).


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16. Eussen SJ, de Groot LC, Clarke R, Schneede J, Ueland PM, Hoefnagels WH, van Staveren WA. Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: a dose-finding trial. Arch Intern Med. 2005 May 23;165(10):1167-72. | link

17. Garcia A, Paris-Pombo A, Evans L, Day A, Freedman M. Is low-dose oral cobalamin enough to normalize cobalamin function in older people? J Am Geriatr Soc. 2002 Aug;50(8):1401-4. | link

18. Hill MH, Flatley JE, Barker ME, Garner CM, Manning NJ, Olpin SE, Moat SJ, Russell J, Powers HJ. A vitamin B-12 supplement of 500 μg/d for eight weeks does not normalize urinary methylmalonic acid or other biomarkers of vitamin B-12 status in elderly people with moderately poor vitamin B-12 status. J Nutr. 2013 Feb;143(2):142-7. | link

19. Rajan S, Wallace JI, Brodkin KI, Beresford SA, Allen RH, Stabler SP. Response of elevated methylmalonic acid to three dose levels of oral cobalamin in older adults. J Am Geriatr Soc. 2002 Nov;50(11):1789-95. | link

30 Responses to “Increased B12 Needs for Adults 65 Years and Older”

  1. Dan Says:

    Interesting information! Thanks, Jack!
    My father takes 100 micrograms of B12 daily and his B12 level is consistently well over 400. He has not had an MMA but I believe his homocysteine was normal (7 umol/L) on 250 micrograms of B12 per day.

    The question is whether normalization of MMA is necessary to achieve proper B12-dependent homeostasis. Some would argue that homocysteine is the more relevant marker, because of its strong correlation with a variety of very bad outcomes. If your homocysteine is normal, and your B12 is >400, there is little value in getting MMA. On the other hand, if your homocysteine is high, it could be due to B12 deficiency, folic acid deficiency (very rare), certain drugs (Dilantin, methotrexate, TMP-SMX – Septra), B6 deficiency, renal failure, smoking or genetic causes.

    In a person with proven B12 deficiency, I’d agree with the higher range and I usually prescribe 1000-1200 micrograms per day. In someone who is already B12-replete, irrespective of age, I think lower dosing could be acceptable. Did any of the studies you cite test for homocysteine levels?

  2. Jack Norris RD Says:


    All the studies looked at homocysteine. I can send you the PDFs if you want to analyze them. Quickly glancing over them, there was no obvious amount of vitamin B12 to take.

    Some B12-related dementia has been independent of homocysteine, so I wanted to focus on MMA rather than homocysteine.

  3. Dan Says:

    Yes please send me the PDFs so I can have a look. This is an important question, and if B12 is of any benefit, it’s likely at least partially driven by homocysteine reduction (as that trial in PNAS strongly hinted).

  4. Dan Says:

    Thanks for sending those along Jack. The homocysteines seem to move in line with the MMAs. I was wondering about the rationale for limiting this dose recommendation (500 micrograms+) to only those people age 65 and above. Aren’t all vegans prone to B12 deficiency, or are you more concerned about older vegans because of the high rates of B12 deficiency with aging and loss of gastric intrinsic factor, acid, etc.

  5. Jack Norris RD Says:


    > or are you more concerned about older vegans because of the high rates of B12 deficiency with aging and loss of gastric intrinsic factor, acid, etc.

    That’s what I’m worried about.

  6. Dan Says:

    Jack, what is your opinion on using nutritional yeast, wheat germ and wheat bran as a source of B vitamins for vegan diets? (obviously not B12, but the other B vitamins specifically)

  7. Jack Norris RD Says:


    I have no particular opinions on it.

  8. Andreas Says:

    Less sexual intercourse, less B12 production. ;)

  9. Dan Says:

    Jack, in the four B12 supplementation studies you analyzed for older patients, do you recall off-hand if they used sublingual or oral (swallowed) dosing? If not, I will check the papers. The paper you have cited in the past comparing oral with sublingual and showing absolutely identical result was done in middle-aged individuals (age around 45-50), so would not apply to the elderly (potentially). If you don’t know or remember, I will crack the papers.

  10. Jack Norris RD Says:


    I don’t recall them mentioning sublingual in any of the papers. If you want me to send you the PDFs, let me know.

  11. Dan Says:

    In the interim, I checked, and none of them used the sublingual route of administration. There is an interesting paper in The Lancet in 1999 which documented excellent absorption of B12 when given sublingually (the oldest patient was 89).

    In elderly people, with decreased intrinsic factor production and frequent achlorhydria, I do wonder if sublingual might be preferable to oral in these folks. Do you have an opinion on that?

  12. Jack Norris RD Says:


    Did the Lancet paper compare it to chewing and swallowing? I haven’t seen any evidence of their being a mechanism to absorb B12 under the tongue.

  13. Dan Says:

    No, they had people hold it under their tongue in contact with their mucosa in a moistened mouth for 30 minutes. No control group, unfortunately. I can send you the PDF if you wish.

    I did not know you were supposed to chew B12 – I thought you only recommended that for the first couple weeks with the high doses in B12-naive vegans. Are we supposed to continue chewing on the lower maintenance dose of 25-100 mcg per day? (in my case I suspect B100 complex would taste disgusting – certainly smells awful and turns my urine bright yellow, thanks to the riboflavin)

    PS: I notice you take some of your supplements twice a day as half-doses … is this more physiological than once daily dosing? I believe you also mentioned it was not good policy to get the entire RDA in a single dose. Makes sense to me, as we humans do not eat once per day, so we are not getting our vitamins and minerals once daily, so why shouldn’t supplements be thought of in the same way? (ie with 2 meals per day)

  14. Jack Norris RD Says:


    I’m not too interested if they didn’t have a control group.

    You don’t need to chew B12 unless you have reason to think that you don’t dissolve the tablet. But to test sublingual versus oral, people should chew just to make sure it’s not a problem with their digestive system not breaking down the tablet versus some sort of mechanism for absorbing B12 under the tongue.

    With almost any nutrient, the more you eat at one sitting, the more the percent absorbs decreases. For B12, I especially want to get it twice a day and since I’m already taking my B12 twice a day, I might as well do the same for calcium and zinc. There’s nothing else I take twice a day, though. If the only beta-carotene I was getting was through carrot juice, I’d try to break it up over the day (and drink with a meal for fat absorption), but I usually have another source of beta-carotene each day.

  15. Dan Says:


    I’ve heard this belief that B12 needs to be taken twice per day from another physician, but when I went to the literature several years ago, there were absolutely no reports on circadian variation in homocysteine or B12 levels – I must admit I did not check for MMA in the keyword search. Thus when you say “For B12, I especially want to get it twice a day” — I assume that’s because “With almost any nutrient, the more you eat at one sitting, the more the percent absorbs decreases.” — and B12 absorption is so readily saturable at low doses.

    I think it’s quite reasonable to take all supplemental vitamins and minerals on a BID or TID basis, to mimic the normal physiology of eating (especially since we are supposed be taking them with meals). OTOH I know you’ve mentioned that iodine could be taken every 2-3 days (if dosed around 150-250 micrograms per day). I don’t know much about the kinetics of iodine absorption. There could be studies on this – they may be hard to find.

  16. Jack Norris RD Says:


    > and B12 absorption is so readily saturable at low doses.

    That’s exactly what I’m saying.

    Vegans should get small amounts of iodine in a variety of their foods, so the supplement is just to top it off. But if the iodine supplement came in smaller doses or easily breakable tablets, then taking less of it more often would seem ideal. However, I do not have any idea what percentage of iodine is absorbed at various doses.

    It would be great if you could research it and write an article! :)

  17. Dan Says:

    Jack, I will have a look at iodine supplementation in the literature. I think most research has been done on iodination of table salt, unfortunately. An alternate would be to add dulse flakes to salad – a single tsp contains 330 micrograms of iodine, well below the upper safety limit.

    Actually my iodine tablets are not hard to cut with a pill cutter and I have been taking them every day. I have seen dose range 75 – 150 micrograms but the most common dose seems to be 650 micrograms.

    Iodine content of plant foods seems highly dependent on local soil iodine levels (unless I am mistaken).

  18. Jack Norris RD Says:

    > Iodine content of plant foods seems highly dependent on local soil iodine levels (unless I am mistaken).

    That is true and in some areas, people might get very little from produce.

  19. Lynn Says:

    What do you think to this? Did you know that nitrous oxide depletes B12? I had a dose at Xmas because I broke my radius. It was compounded so I had it manipulated with the help of nitrous oxide. After this episode I was very depressed and down and showing signs of a deficiency. I hadn’t heard the B12/nitrous oxide theory. I am a vegan and 65. The consultant said she didn’t think one dose of N20 would have any effect. What do you think? Lynn

  20. Jack Norris RD Says:


    I am aware of nitrous oxide depleting vitamin B12. I very briefly mention it on this page:

    It is a concern for anyone with low vitamin B12 levels. Any idea what your levels were before the nitrous oxide? Do you regularly supplement? Here are my recommendations to re-establish your B12 stores:

    See Step 1.

  21. Karen Says:

    Hello Jack – I’m not a vegan or vegetarian, but I’m reading your column with interest (the one about b12 analogues is very informative). The points I’m putting forward for consideration relate to the reason for over 65′s being more susceptible to a b12 deficiency – as age increases stomach acid decreases = less absorption (not only of b12 but other minerals and vitamins) However this condition (achlorhydria or hypochlohydia) is not not limted to the more elderly. In fact, historically this was one of the most formative causes of b12 deficiency (or pernicious anaemia) and in most studies the patients were under 50 years of age.
    Also, have you done any research into the fact that ‘all’ haematological indicators return to normal once b12 treatment commences? I ask this question because getting diagnosed with b12 deficiency is pretty much a nightmare. In the past, when the only blood tests available were RBCs, reticulocytes etc, it was also known that not only were these very easily remedied but that they were only one ‘possible’ symptom ie they were not a diagnosis. Now we have the situation that although recent guidelines tell doctors the situation is the same (once treatment commences all haematological indicators return to normal) those inaccurate bloods are relied on for a diagnosis. Serum b12 is very easily remedied – the MMA situation is not so clear. Which is why I ask the question if you personally have looked at this situation?

  22. Jack Norris RD Says:


    I’m not following what you’re asking exactly, but my guess is that I have not looked into this in the detail for which you are asking. I am not an expert on pernicious anemia or the blood parameters and responses surrounding it’s treatment.

  23. Karen Says:

    That was quick!

    Trying to focus directly on vegetarians (I’m leaving vegans out of the equation) but the situation (relating to bloods) is that many veggies take a supplement (whether this be in small or large amounts) however, that supplement can rectify a serum b12 level – I don’t want you to quote me, but I think a recent study stated that as little as 3mcgs taken every day for 10 days, can push serum b12 levels into normal. So, you have a veggie (sorry if I’m offending!) that has physical symptoms of b12 deficiency eg, sore tongue, vision issues, hot soles of the feet, but they are taking a supplement that is not enough to rectify at cellular level and stop nerve/cell degeneration, but the supplement has masked the diagnosis in the serum b12.
    So now you have a patient with a potentially serious problem. They are getting nerve degeneration but they can’t prove it. Once the serum b12 is into normal doctors state b12 deficiency can’t be the cause of the remaining symptoms.
    I understand that the MMA also reverts to normal with the supplementation but I am unaware of how quickly or effectively this can happen. And obviously you don’t either – but this is one heck of a complex subject.
    However, I hope you can see from the above that vegetarians that supplement even small amounts can mask the haematolgical diagnosis. When also think about and take into consideration the b12 veggies take in through the diet via milk, eggs, cheese, yogurt etc, they should be getting the requisite amount of b12 according to the RDAs. Yet they still have problems. Would this suggest that most veggie diets are not the cause of b12 deficiency but due to a malabsorption problem of some kind? (like the rest of us)
    I think this is a very important issue, because for a vegetarian who supplements (even small amounts) getting a diagnosis of b12 deficiency is extraordinarily difficult.

  24. Jack Norris RD Says:


    Okay, I think I understand. I don’t think 3 micrograms per day for 10 days can normalize B12 levels unless the levels were not very low to begin with. I’d be interested to see that research. 2,000 micrograms per day for a few weeks can, though:

    I think it’s fairly safe to say that if you are taking enough B12 to normalize your vitamin B12 levels, then you should not be experiencing further damage due to B12 deficiency. I have not seen anything to the contrary in the medical literature. This would also be true of normalizing MMA levels, which is the best way to determine a functional B12 deficiency. High folate intakes can mask the anemia that might otherwise be apparent from a B12 deficiency.

  25. Karen Says:

    I had a quick peek.
    This 10 thing may be significant. I haven’t got the link to the other study but when Murphy and Minot were testing their treatment they found that the raw liver that was fed rectified bloods after 10 days.

    Maybe it isn’t the amount that is significant but the duration?

    Okay, I’m gonna challenge you on the other bit (it’s important that I do and you’ll see why)

    The serum b12 test is between 20 -80% inaccurate. One reason is that it measures all b12 in the blood stream – not only transcobalamin II – which is the only kind that is utilized by the nerves and cells. The tII then still has to be transported to the nerves and cells effectively.
    Not only that, the serum b12 test is an acute phase reactant. This mean that it gives a falsely elevated reading if the patient is stressed.
    Also the normal range given is set at a point where healthy people would have levels monitored. As an example – I have b12 deficiency due to malabsorption. If I take b12 orally only 1% is absorbed via passive diffusion. If I am injected I have a malabsorption problem (as above) which means I need a lot more than say you do to enable it to get to my nerves and cells.
    You don’t have a malabsorption problem, therefore when you eat that b12 is both absorbed effecively and stored effectively and so you level is expected to be somewhere in between e.g. 200-700. I, on the other hand, need to see my b12 levels way over the top end – off the scale.

    The serum b12 test for people who have a b12 absorption problem is effectively next to useless, apart from, possibly the initial diagnosis. But as you point out folate can mask it and I would add that iron deficiency can also mask it.

    Am I making sense?

  26. Karen Says:

    Sorry about the typing errors – I’m tired and so my eyes and fingers don’t work effectively!
    Sorry, sorry, sorry.

  27. Jack Norris RD Says:


    I’m the king of typos, so I can’t get too bent out of shape about yours. :)

    I can’t speak to your situation if you have a B12 metabolism defect. But for most people, the relevance that most B12 in the serum is not on TCII is minimal. At some point, when or if the body needs it, the B12 will be passed off to TCII and will get to the cells. An analogy would be between serum ferritin and transferrin. Only the iron on the transferrin molecule will get to the tissues, but serum ferritin is still a very useful diagnostic test to determine iron stores and if necessary, the iron on ferritin will be passed of to transferring and transported to the cells.

  28. Karen Says:

    Okay, early morning, let’s see if the fingers are working!

    For different reasons the TCII can not get transported but they are not minimal. In the same way that there can be a shortage of TI to carry the TII.
    The latest research shows that there are at least 14 proteins involved and it can go wrong any step of the way.
    If you add on to that stomach acid issues and the fact that in malabsorption cases the bile system ie the enterheptic circulation doesn’t work then many people are likely undiagnosed. Or diagnosed but undertreated and thus have normal serum b12 levels but are still suffering cellular damage.
    Ferritin is also an acuate phase reactant.
    So you have 2 potential malabsorption situations where both serum tests are immediately potentially lacking in sensitivity.

    What we are doing, that is different to medicine in the past, is relying – on one or the other – on diagnosing a potentially lethal illness on the strength of blood tests that in themselves have been proven not to be accurate. We are also discounting physical symptoms if these bloods are normal.

    How ridiculous this is can be drawn by a simple analogy.
    Vets are taught about b12 because in livestock it manifests as a wasting disease usually in the young. They also know that if b12 deficient animals get through the food chain and start making people ill, then someone can be held responsible.
    So, a farmer has some lambs that are losing ground. They are are losing some fleece. The vet knows that the serum b12 is an acute phase reactant but despite that chases them a few times around a field before testing.
    The test comes back in the normal range. The vet refuses to treat and puts the symptoms down to something else and the animals continue to decline.
    I would respectfully suggest that in that scenario, a farmer could well throttle a vet!
    But it’s what we do to people (not throttle, refuse to treat)
    A vet would not get away with not providing the correct medication when the physical symptoms indicate otherwise. They just wouldn’t.
    Yet in human medicine patients are in the position of proving medical symptoms in the face of a blood test (or blood tests) that is known to be inaccurate. And even if that test were only 1% inaccurate (it’s a lot more though) and we are dealing with a potentially lethal illness then the outcome can be potentially fatal for that 1% of patients. Fine if you’re not the 1%.

    When it comes to the problems with the normal ranges etc, it has to be understood that the test was originally designed to identify when a person was b12 deficient prior to treatment. Hence you get the standard normal ranges. After treatment, if there is a suspected malabsorption problem, then of course you are not looking to get levels within the normal range – because you don’t have normal absorption. It’s no use me having a b12 level of 300 the same as you, because only a small proportion of my b12 is getting through.

    My point when it comes to vegetarians (not vegans again) is that on a standard veggie diet (I’m including dairy products and eggs in this) a veggie who does NOT have a malabsorption problem should be getting enough b12 according to the RDAs. It should be easy looking at the figures. So, if they are symptomatic (physically) then is it not the diet that is the problem but absorption?
    I’ve seen so many veggies that have symptoms, but supplement and so b12 levels are normal, and so they don’t get treatment.
    It’s hard enough for people who aren’t veggies to get the correct treatment, nightmare for them I’d presume. Which is why I’m here posting, because the risks of not getting this illness treated properly, for whatever reason, can be very, very serious.

  29. Karen Says:

    … and I found this link.
    The study was done in light of folate supplementation but it shows how low dose (in some cases very) can increase the serum b12 level.
    If we do, eventually, agree that bloods (particularly the serum b12) are not accurate markers in respect of what is going on at cellular level, then you could see how a veggie taking a low dose supplement may also mask a cellular b12 deficiency.
    Doctors, in the UK and France at least, will establish if problems are being caused by a b12 deficiency, firstly by taking anaemia into consideration (many patients don’t have anaemia) and then, if you’re lucky, taking a serum b12.
    For the patient that is supplementing both with folate and b12 – there are no haematological markers.

    Oh, and here’s the link

  30. Jack Norris RD Says:



    Interesting study. An average increase of ~50 pmol/l isn’t that much, but your point is taken. 80 µg/day is also not very much for elderly people (as you can see above, I recommend 500 to 1,000).

    > I’ve seen so many veggies that have symptoms, but supplement and so b12 levels are normal, and so they don’t get treatment.

    I haven’t seen this. But I completely agree that if a vegetarian has symptoms of B12 deficiency, having normal levels should not rule out B12 deficiency.

    Can you explain where you see these vegetarians? Are you a health practitioner? And what are their symptoms?

    In the comment you made that you suggested I don’t post, you said:

    > Also, I think it was on your site that you made the comment that we need enough farm animals to fertilize the land to grow the veggies. I’ve been saying that for years.

    No, I didn’t make that comment. I think that if animals were no longer farmed, we could use compost or something else in the place of their manure. I have never looked into it in detail, but I’m sure the human race would be inventive enough to think of something without needing to kill animals.

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