Will a Multivitamin Cover B12 Needs?

Is a typical daily multivitamin with 100% RDA of B12, taken once a day, sufficient to reliably cover my B12 needs?

Quick answer:

No. The RDA for vitamin B12 is 2.4 µg. I recommend getting at least 25 µg per day if only getting B12 in one dose per day.

Note that nutrition labels on supplements usually show the percentage of the Daily Value, not the RDA. The Daily Value for B12 is 6 µg, which is still not enough.

Longer answer:

The body can absorb B12 two ways:

1. Using transport proteins that ferry B12 from the digestive tract into the blood.

2. Through passive diffusion without any transport proteins.

The transport proteins get saturated at about 1.5 µg while only 1% to 1.5% of B12 is absorbed through passive diffusion. Because of this, I recommend 25 to 100 µg if only getting B12 in one dose per day.

More information:

Vitamin B12 Recommendations

Vitamin B12: Are you Getting It? – How Recommendations Were Formulated

Table of Daily Recommendations – Shows amounts needed for two daily doses, one daily dose, and two weekly doses.

28 Responses to “Will a Multivitamin Cover B12 Needs?”

  1. A Daily Multivitamin Won’t Cover Your B-12 Needs Says:

    […] chance: take a cheap sublingual B-12 every few days, hopefully in addition to a daily multivitamin. Link. Spread the […]

  2. Vitamin B12: Help needed! | Vegan für Anfänger und Fortgeschrittene Says:

    […] This article at Jack Norris RD was a great reminder that you should really check the labels. One pill of VEG 1 only contains 10 µg. A lot of people recommend taking AT LEAST 25 µg (and up to 100 µg) a day because of the low absorption rates (when you take only one serving of B12 a day the absorption rate is lower than when you take multiple servings). […]

  3. m Says:

    I take a 1000 µg supplement twice a week. From what I’ve read there are no known risks with high B12 intake. If so, then we should, given the risks of going low, ramp up B12 for vegans wherever we can. Those not taking a dedicated B12 supplement would at least be somewhat better off with that and we who supplement already aren’t worse off.

    One way to do that is through fortification of food products like soymilk and soy meats. I doubt the amount of B12 in soy milk is a cost issue. They likely just stick to RDA. Maybe we should campaign for increasing the dose across the board for fortified products? For smaller vegan food brands I think even a minor campaign has good chances.

  4. Stefan Says:

    Dear Jack,
    I swallow a daily multivitamin tablet which contains 250mcg B12 as Methylcobalamin. Because I am unsure about the absorbtion rates of Methylcobalamin I also take 1000 mcg Cyanocobalamin sublingual three times a week.
    Are there really no risks with high B12 intake or a kind of upper limit?

  5. Therese Says:

    Hi Jack,

    I have some questions regarding vitamin B12 supplements.

    My husband and I consume some vitamin B12 from fortified foods (about 2.7 mcg/day from fortified cereal and soy milk), but we also started taking a daily multivitamin containing 10 mcg vitamin B12. I later realised that 10mcg per day in supplement form is probably not enough, so we also started taking a weekly chewable vitamin B12 supplement of 1000mcg (it sticks to one’s teeth though, should this be cause for concern?).

    Do you think that the combination of fortified foods, daily multi-vitamin and weekly chewable supplement adds up to enough vitamin B12?

    If we were to stop taking the 10mcg daily supplement, do you think that 2.7 mcg B12 daily from fortified foods in addition to a weekly chewable B12 supplement would add up to a sufficient amount, or would it be best to up the 1000mcg supplement to twice weekly?

    I started taking the multivitamin because it’s a source of vitamin B12, vitamin D, selenium, iodine and a few other B vitamins. However, I have now ordered a separate vitamin D supplement as the multivitamin only supplies 10mcg vitamin D. I’m considering using separate supplements instead of a multi-vitamin, unless I find one with adequate amounts of the relevant vitamins and minerals.

    PS – Great work on Vegan for Life, awesome book. =)

  6. Jack Norris RD Says:

    Therese,

    > If we were to stop taking the 10mcg daily supplement, do you think that 2.7 mcg B12 daily from fortified foods in addition to a weekly chewable B12 supplement would add up to a sufficient amount, or would it be best to up the 1000mcg supplement to twice weekly?

    Yes, that should be enough.

    > (it sticks to one’s teeth though, should this be cause for concern?).

    No.

    > Great work on Vegan for Life,

    Thanks!

  7. Chiari Says:

    I take a Deva Vegan Multivitamin and mineral tab. I break the capsule in half and take them two halves about 12 hours apart. There are 100 mcg B12. Is that enough?

  8. Jack Norris RD Says:

    Chiari,

    Yes, that is enough.

  9. Joshua Says:

    Hey Jack,

    I was wondering, I take a Deva vegan multivitamin and mineral pill. It has 1666% of your daily B12 intake. Is this enough and will it absorbed?

    I will also get more B12 when I have a daily glass of soy milk and sometimes, mock meats.

    Should I be taking more B12 even with my daily vitamin?

    Thanks, Josh

  10. Jack Norris RD Says:

    Joshua,

    That should be plenty of vitamin B12. Unless you have reason to think your are not digesting the tablet, I would assume it is absorbed. One way to test – I assume there is plenty of vitamin B2 in the multi. Vitamin B2 will turn your urine a bright yellow for a few hours after taking it, so if your urine is yellow, you know you’re digesting the tablet.

  11. Rita Says:

    Hi, Jack – Thanks for all the great info: we take VEG 1 supplement (1 daily)from the british vegan society – specially formulated for vegans with 1000 mcg of B12 – plus fortified soy milk and occasional marmite: – this should be OK, no?

  12. Jack Norris RD Says:

    Rita,

    25 micrograms per day is enough, so yes, you are well covered.

  13. Stefan Says:

    Hi Jack,

    you forget to answer my question:
    Are there really no risks with high B12 intake (especially cyanocobalamin) or a kind of upper limit?

    Many thanks for your help and your book.

  14. Sarah Says:

    Do you have any information about B12 supplementation for children? My 4-year-olds take a daily chewable multivitamin with 6 micrograms of B12 as cyanocobalamin, and they drink a cup of fortified soy, almond, or rice milk one or two times a day. I’m concerned after reading this article that they might not be getting enough B12. I haven’t seen any separate B12 supplements for children–is it ok to give them one that is formulated for adults?

  15. Jack Norris RD Says:

    Sarah,

    If you take a look at this chart, it lists the requirements for all ages. The amounts you say your kids are getting should be plenty.

    http://veganhealth.org/articles/dailyrecs

  16. Jack Norris RD Says:

    Stefan,

    There are no known risks at the amounts I recommend, although I occasionally hear from people who have allergic-type reactions to large does of B12. That said, it’s always a good rule to not take more than what is recommended unless there is a good reason to do so.

  17. Rita Says:

    I forgot to ask something which might interest others here – I’ve read that Metformin interferes with the absorption of B12, but amounts were not mentioned – could this be a problem for vegans taking this medication?

  18. Jack Norris RD Says:

    Rita,

    Yes, it could, but it has nothing to do with their being vegan. Vegans taking metformin should consult their physician on how much vitamin B12 to take. I would guess that 1,000 micrograms per day would be a good start.

    http://diabetes.webmd.com/news/20090608/metformin-linked-to-b12-deficiency

  19. veganimal Says:

    It seems a bit counter intuitive that you don’t get enough B12 when you consume 100% of the RDA. It seems like faulty labeling.

    From Wikipedia:
    “Recommended Dietary Allowances (RDA), the daily dietary intake level of a nutrient considered sufficient by the Food and Nutrition Board to meet the requirements of nearly all (97–98%) healthy individuals in each life-stage and gender group.”

  20. Jack Norris RD Says:

    Veganimal,

    The RDAs are created with the idea that nutrients are eaten throughout the course of the day rather than in one dose. I would imagine that at some point in the future they will separate the B12 RDA into categories based on how many doses per day or week someone is taking them. Another thing to keep in mind is that the B12 RDAs are not created to minimize homocysteine levels but rather only to prevent acute deficiency.

  21. friendlytoanimals Says:

    Hi there,
    I’ve been vegan for oh, about 17 years? I mostly just try to eat good whole foods and don’t do a lot of supplementing, but about 10 years ago I tried supplementing b12 and within a few days I broke out in acne, which an internet search led me to believe can be a result of too much B12. From this I decided I was getting enough from my diet and stopped supplementing.
    Reading through this thread I see you (Jack) say that “some people have allergic type reactions”. Makes me re-think a little. Could the acne be not so much indicative of getting enough B12 before supplementation but rather just an allergic response? And if so, how can one insure good B12 levels without reaction? My house does stuff like make home made almond milk, so we don’t ingest huge amounts of fortified foods these days.
    thanks for any input!

  22. Jack Norris RD Says:

    friendlytoanimals,

    > Could the acne be not so much indicative of getting enough B12 before supplementation but rather just an allergic response?

    Very interesting. I hadn’t been aware large doses of vitamin B12 causing acne. I need to look into this more but from what I see here, it sounds plausible that your acne might have come from high doses of vitamin B12. In that, case you just need to experiment with taking lower doses. My guess would be that this reaction is mostly independent of current vitamin B12 stores.

  23. Tanya Says:

    Hi jack.
    I have been vegan for about 6 years and vegetarian for probably 20 and apart from eating fortified foods and soy milks I haven’t ever taken a regular B12 tab. Since reading your excellent articles I’ve recognized possible signs of B12 deficiency – im fatigued a lot, foggy mental processing, poor memory, mild signs of depression (that I’ve never had before!!). I’m keen to get on top of this! What sort of dosage would you recommend I start taking to boost my levels quickly, and for how long before I go back to a “normal dose”? Thanks SO much!!

  24. Jack Norris RD Says:

    Hi Tanya,

    Here are my recommendations:

    http://veganhealth.org/b12/rec

    I don’t want you to be fooled by a placebo effect, so I will point out that those symptoms could be found with a lot of different deficiencies, not just B12. But B12 is a good place to start. It would be good to know if your symptoms improve – keep me posted if you care to.

  25. Chris Says:

    Hi Jack, I take a Healtheries men’s multivitamin once a day. Each tablet contains 40mcg of Cyanocobalamin (B12). However, I usually swallow the tablets rather than chew or dissolve them as I really don’t like the taste. Do you think this is adequate for getting an essential dosage of B12? Thanks!

  26. Jack Norris RD Says:

    Chris,

    The only reason why someone would need to chew the tablets is if they are not able to digest them properly such that they do not dissolve. Most people will be able to digest the tablets, but people with digestive problems, such as weak stomach acid, might not in which case swallowing 40 micrograms whole will not work. Odds are that any given person, especially people 50 and younger, can digest the tablets; but, of course, I do not know whether you are able to or not.

  27. madhu Says:

    Hi Jack i have b12 deficiency and had 20 b12 injections as a course prescribed by neurologist but after that my eyesight has increased , i also had acne and skin rashes , few online sources say that b12 leads to faster loss of vision , please suggest me some remedy, as i am a vegetarian i opted for injections but as i said its affecting my vision , Thanks !

  28. Jack Norris RD Says:

    madhu,

    I don’t understand what you are asking me. How to take B12 without getting rashes?

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