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Vitamin B12 Deficiency & Supplementation


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I too read the article with interest. Thanks Ron.

In modest support of the idea Saul posits that higher serum B12 may be a marker for higher animal product (esp. meat) consumption is the fact that one of the only other variables that went up substantially between B12 quartiles in the study population was serum ferritin. Here is the table from the paper:


A recent meta-analysis [1] found that meat eaters had significantly higher serum ferritin levels than vegetarians.

Seems like more reason to eat mostly plants in place of meat, and perhaps for vegans keep B12 supplementation to not much above the RDA.



[1] Crit Rev Food Sci Nutr. 2018 May 24;58(8):1359-1374. doi:

10.1080/10408398.2016.1259210. Epub 2017 Jul 5.

The effect of vegetarian diets on iron status in adults: A systematic review and 

Haider LM(1), Schwingshackl L(2), Hoffmann G(3), Ekmekcioglu C(1).

Author information: 
(1)a Department of Environmental Health , Center for Public Health, Medical
University of Vienna , Vienna , Austria.
(2)b Department of Epidemiology , German Institute of Human Nutrition , Nuthetal 
, Germany.
(3)c Department of Nutritional Sciences , University of Vienna , Vienna ,

BACKGROUND: Vegetarian diets exclude meat, seafood, and products containing these
foods. Although the vegetarian lifestyle could lead to a better health status in 
adults, it may also bear risks for certain nutritional deficiencies.
Cross-sectional studies and narrative reviews have shown that the iron status of 
vegetarians is compromised by the absence of highly bioavailable haem-iron in
meatless diets and the inhibiting effect of certain components present in plant
foods on non-haem iron bioavailability.
METHODS: The databases Pubmed, Scopus, Embase, and Cochrane CentralRegister of
Controlled Trials were searched for studies comparing serum ferritin, as the
major laboratory parameter for iron status of adult vegetarians with
non-vegetarian control groups. A qualitative review was conducted as well as an
inverse-variance random-effects meta-analysis to pool available data. In addition
the effect of vegetarian diets according to gender was investigated with a
subgroup analysis. The results were validated using a sensitivity analysis.
RESULTS: A total of 27 cross-sectional studies and three interventional studies
were selected for the systematic review. The meta-analysis which combined data of
24 cross-sectional studies showed that adult vegetarians have significantly lower
serum ferritin levels than their non-vegetarian controls (-29.71 µg/L, 95% CI
[-39.69, -19.73], p < 0.01).
Inclusion of semi-vegetarian diets did not change
the results considerably (-23.27 µg/L, 95% CI [-29.77, -16.76], p < 0.01). The
effects were more pronounced in men (-61.88 µg/L, 95% CI [-85.59, -38.17], p <
0.01) than in both premenopausal women (-17.70 μg/L, 95% CI [-29.80, -5.60], p < 
0.01) and all women (-13.50 μg/L, 95% CI [-22.96, -4.04], p < 0.01),
CONCLUSIONS: In conclusion our results showed that vegetarians are more likely to
have lower iron stores compared with non-vegetarians. However, since high iron
stores are also a risk factor for certain non-communicable diseases, such as type
2 diabetes, it is recommended that not only vegetarians but also non-vegetarians 
should regularly control their iron status and improve their diet regarding the
content and bioavailability of iron by consuming more plants and less meat.

DOI: 10.1080/10408398.2016.1259210 
PMID: 27880062  [Indexed for MEDLINE]

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  • 2 weeks later...

Dean and Saul, good find, I fully agree meat may be one issue here. But it’s still an open question. The mortality figures look to me as if something more than just eating meat is at play here, but a factor I don’t doubt. Supplementation is a dicey game as we have seen so many times.


Dean you say above that perhaps vegans should not supplement much beyond the Rda.  I believe MR has switched to a similar strategy in light of all the bad news on b12.  I do recall that you supplement 1/6 of a 100 mcg b12 supplement. That’s about 600% of the rda.

Are you reconsidering that?

Mike Colella

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As as strict vegan, evidence suggests it is important to supplement with B12, and it isn't easy to do targeted B12 supplementation and get less than I get by nibbling a bit off a 100 mcg B12 tablet each day. 

More importantly, my supplementation strategy puts my serum B12 level in the middle of the range of subjects in this study (about 400 pg/ml). In their adjusted model, there was no statistically significant increase in all-cause mortality for subjects with my level of serum B12. 

Plus, as discussed above, elevated serum B12 may be a marker for high meat consumption, and the accompanying deleterious effects of that (e.g. high TMAO), which doesn't apply to me.

So beyond maybe trying to nibble off a bit smaller piece of my B12 tablet each morning, at this point I'm not reconsidering my B12 supplement strategy.


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Hi Dean!

I agree.  My primary physician, who is a young gerontologist, recommends that older adults -- including me (grammatically incorrect -- should say "I" 🙂)  -- should heavily supplement B12, even if they eat meat.  He believes -- and I do as well -- that testing serum levels is the way to know the success of your B12 supplementation.  My serum levels with my current supplementation are good.

And, as I indicated, I'm skeptical if the results in the article are measuring the dangers of excessive B12, or rather the dangers of meat.

   --  Saul  

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Here is a strategy that I might switch to in order to get closer to the RDA of B12. These caffeinated mints have 21 mcg of B12, which is "only" 880% of the RDA. They are quite a bit bigger than the 100mcg B12 tablets I nibble on now. I may try nibbling a small chuck of one of these mints each day, getting me closer to only 100% of the RDA. 

The mints are made in an FDA-approved facility in Canada, which is reassuring. But still, relying on a mint candy manufacture to formulate, produce and label their product accurately is somewhat of a risk. I think I may break out a couple of these mints and a 100mcg tablet (from Solgar) into small pieces, mix them together, and eat one piece each day, for extra insurance.


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I talked to the guys at Viter who sell the B12-fortified caffeinated mints. Whether it was a result of me telling them about the study we're discussing or of their own accord, they are planning to reduce the B12 level in future batches of their mints to 100% of the RDA per mint. The new formulation should be available in a couple months.

Alternatively, you could try brushing with a small amount of B12-fortified toothpaste (like this one) to get a near-RDA dose of B12. Here is an update from Jack Norris (founder of very informative, science-based website VeganHealth.org) discussing the efficacy of B12-fortified toothpaste. Looks pretty effective.


B12 Toothpaste in Vegans

A 2017 randomized, double-blind, placebo-controlled trial was the first to test the efficacy of vitamin B12-fortified toothpaste in raising blood markers of vitamin B12 status (1). The trial was conducted in Germany and included 66 vegans. 22 participants in the placebo group and 31 in the intervention group were taking B12 supplements; they were asked to continue their supplementation behavior throughout the study).

Participants were instructed to use the study-issued toothpaste twice a day, brushing for two minutes each time. The treatment toothpaste contained 100 mcg B12/g toothpaste. Researchers estimated participants received 130-290 mcg B12 per day via the toothpaste, but were not able to calculate or measure how much B12 the participants absorbed.

At the end of 12 weeks, compared to their baseline values, participants in the intervention group experienced significantly increased B12 (from 197±137 to 279±134 pmol/L; p=0.001) and holotranscobalamin (from 35±35 to 64±34 pmol/L; p<0.001), significantly decreased methylmalonic acid (MMA) (from 0.303±0.361 to 0.212±0.123 µmol/L; p=0.001), and not-quite-significantly decreased total homocysteine (from 10.6±6.2 to 9.7±6.4 µmol/L; p=0.058). These changes are associated with improved B12 status.

Changes were greater in those reporting not taking B12 supplements. Participants in the placebo group did not experience significant changes in their B12 markers between baseline and the end of the intervention.

Based on this study, it appears that B12-fortified toothpaste may serve as a viable source of vitamin B12 for vegans.

B12 Toothpaste in Older Adults

A 2019 randomized, double-blind, placebo-controlled trial assessed the efficacy of vitamin B12-fortified toothpaste in a sample of 92 older adults (2). After 3 months, those receiving the treatment toothpaste (100 mcg B12/g toothpaste) experienced significantly greater B12 levels (368 vs. 295 pmol/L; p = 0.005) compared with the placebo group. Researchers concluded that B12-fortified toothpaste may be used to help prevent vitamin B12 depletion in older people.


1. Siebert AK, Obeid R, Weder S, Awwad HM, Sputtek A, Geisel J, Keller M. Vitamin B-12-fortified toothpaste improves vitamin status in vegans: a 12-wk randomized placebo-controlled study. Am J Clin Nutr. 2017 Mar;105(3):618-625. doi: 10.3945/ajcn.116.141978. Epub 2017 Jan 4.

2. Zant A, Awwad HM, Geisel J, Keller M, Obeid R. Vitamin B12-fortified toothpaste improves vitamin status in elderly people: a randomized, double-blind, placebo-controlled study. Aging Clin Exp Res. 2019 Dec;31(12):1817-1825. doi: 10.1007/s40520-019-01125-6. Epub 2019 Jan 24.

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  • 3 years later...

Adding 2 cents based on a fresh own observation.

I am midaged, running plants only diet, with 2 meals a day and a small snack between them.

I have some experience with b12 deficiency anemia and some subtle feelings of it when I finally learned the things.

The last time I got it was a mistake I did when switched the supplement and used to have 0.5mg daily instead of 1mg previous months. When slight breathe shortage, nail waives, slight but characteristic weakening in knees going upstairs manifested I discovered the issue, doubled the dose and the sympthoms disapeared.

I did urine MMA test and it was normal.

Recently I discovered even more subtle breathe-related small timeframe incident that is hardly distinguishable (and a visible wave on one nail) but when I did urine MMA as a part of larger test I was surprised to see it slightly elevated 1.95 (should be lower than 1.89).

(An interesting thing is that my CBC+reticulocites test looks the most fit into the normal values than ever before, characteristic slight elevation of MCV paired with hemoglobin on lower normal is even more normal than in all previous tests, so such subtle state is not distinguishable with CBC test in that case.)

Both times I used methylcobalamine from different inexpensive vendors.

The difference between these two casesis is in dosage and regimen, the better one was 2x0.5 before the meals and the current one is 0.95 before the meal in the morning.


I remember here and in other places there were recomendations to distribute the supplement into several doses, use of lozinges, ascorbic acid and other tricks to increase the chances to get it absorbed and warehoused in the liver and I think these advices make sense. I personally will switch to 2x0.5 again as an easiest way to get ok but I think the topic is an important thing for plants-only dieters, especially with age, so MMA test is a must for them.





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