B12 Status of Whole Foods Vegans Consuming Nori and Mushrooms

Summary A German study suggests that whole foods vegans who do not supplement with vitamin B12 have subpar vitamin B12 status and that nori and dried mushrooms do not improve B12 status.

In a 2014 study from Germany (1), a group of 10 whole foods vegans, who did not take supplements, were found to have methylmalonic acid (MMA) levels of almost 400 nmol/l. MMA is the most specific way to measure vitamin B12 status, with healthy levels being 270 nmol/l or less.

A second group of vegans who supplemented – it’s not clear with how much but it seems to have been at least 2 doses of 1,000 µg/week of B12 on average – had MMA levels of just above 200 nmol/l.

The whole foods-only vegans were given a minimum of 12 g/week of nori and 15 g/week of sun dried mushrooms, which the researchers calculated to contain an average of 3.1 µg/day of vitamin B12; the RDA is 2.4 µg. Their MMA levels were measured every 2 months for 8 months and they did not dip much below 350 nmol/l.

The vegans who took supplements were given more B12 than normal (though it’s not clear how much), and their MMA levels steadily decreased to about 150 nmol/l at 6 months, but then back up to 200 nmol/l at 8 months.

This research indicates that at the amounts given, nori and sun dried mushrooms do not improve vitamin B12 status.

I have updated the VeganHealth.org article B12 in Plant Foods with this information.

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1. Schwarz J, Dschietzig T, Schwarz J, Dura A, Nelle E, Watanabe F, Wintgens KF, Reich M, Armbruster FP. The influence of a whole food vegan diet with Nori algae and wild mushrooms on selected blood parameters. Clin Lab. 2014;60(12):2039-50. | link

5 Responses to “B12 Status of Whole Foods Vegans Consuming Nori and Mushrooms”

  1. Brandon Becker Says:

    It’s good to finally see a study done with humans rather than rats. Even though the non-supplementing vegans turned out to be low in B12 and D, it’s helpful to see that they were good on everything else.

    The study says they ate a minimum of 12g a week of nori. I eat about 35g a week. Does the study have anyone eating that much? I don’t eat seaweed for B12; I eat it for iodine and because it tastes good. For B12, I rely on B12-fortified soy milk and take a B12 supplement. My doctor said last year that I could stop the B12 supplement given that my blood levels are in the 900-range but I’ve only cut back so far since I wanted to finish off the bottle.

  2. Jack Norris RD Says:


    > Does the study have anyone eating that much?

    They didn’t report how much any given individual was eating.

  3. jonathan wilson Says:

    I am currently living in Kazakhstan and the only B12 supplement available is 500mg cyanocobalamin B12 (saline) ampules, I have been drinking the solution, is it safe to do so and is it as effective as if I were taking a 500 microgram tablet?


  4. Jack Norris RD Says:


    I assume you mean it’s intended for B12 injections? I don’t know if it’s safe to take something like that orally. Can you order B12 supplements from out the country to be shipped to you?

  5. jonathan wilson Says:

    Thanks Jack,

    Yes, it’s meant for injections, I’ve been taking it like this for 2 months, with no noticeable side effects, but big improvements in memory. I’m using it as a stop-gap until I get some B12 tablets in the UK next month.

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