Additional sources of vitamin B12 for vegans (and raw vegans too!) – Part I


I already talked about where you can get vitamin B12 if you have a “raw” and “vegetative” view on the world. However, there are other sources of vitamin B12 for vegans that really worth to chat about, so I would like to build on what I already said.

If you recall, I suggested  that as a raw vegan the sure way to get B12 is either by consuming soil-contaminated plants or by taking a methylcobalamin supplement (the most bioavailable form of B12). And if you are willing to do some exceptions, you can also get vitamin B12 from raw egg yolks (one per week is enough). In general, potential B12 foods are constantly being debated and argued over. Among them are fermented foods, sea vegetables and mushrooms which I am going to discuss. Another one which you are probably not familiar with is plants existing in symbiosis with B12 bacteria. Today I will go through fermented foods and sea vegetables and leave mushrooms and plants living in symbiosis with B12 bacteria for the next post.

Before I dive into discussion a bit of refreshing on vitamin B12. First of all, the only organisms that can make vitamin B12 are bacteria and archaea. Thus, vitamin B12 found in all land and sea animal foods as well as plant foods at some point had to pop up from the bodies of these two simple bugs. The B12-producing bacteria lives in soil, water and guts of some groups of animals. While B12-producing archaea, a single-celled critter, which evolved separately from bacteria, lives in extreme places like salt lakes and deep ocean waters. Health sciences mostly focus on bacteria as it is responsible for majority of known B12 production. Although these 2015 findings suggest that marine archaea can considerably contribute to B12 found in marine organisms which humans like to put on their plate as well. Also, recall that similar to some other animals, your gut is also a source of B12-producing bacteria. However, how much B12 is produced in your gut depends on the health of your microflora. It is said that vegans have it in a much better state than non-vegans folks. It is very likely, however, assessing the health state of gut microflora is difficult and because B12 deficiency can cause irreversible damage to the nervous system, relying on intestinal B12 is risky. Even if you are a long-time vegan. Counting on intestinal B12 is further complicated in that B12 produced by some species of gut bacteria can be consumed by other species ultimately leaving less for you to absorb.

All right, ready to discover vitamin B12 somewhere else? Keep in mind that it is recommended to take 2.4 μg (micrograms) of vitamin B12 every day.



Fermented foods

Additional sources of vitamin B12 for vegans (and raw vegans too!) - tempeh

Tempeh (note that soybeans are whole)

A quick brush over the fermented foods.

Contrary to some consensus that you can get B12 from fermented foods, in reality, fermentation bacteria like Lactobacillus species used to ferment foods produce only marginal levels of B12. For example, fermented Korean vegetables kimchi contain less than 0.1 μg of vitamin B12 per 100 g (grams). On the other hand, tempeh, which is known  to contain B12 (up to 8.0 μg per 100 g) does so only because during production it gets contaminated with strains of B12-producing bacteria. If you are not familiar with tempeh – it is similar to tofu but made from whole soybeans which are cooked and then fermented with a special species of mold. The caveat is sometimes soybeans may pick up B12 bacteria during preparation, sometimes not, thus tempeh is not a satisfactory B12 source. Moreover, cooked beans don’t fit the philosophy of raw vegans…

There is one quite unexpectant fermented food with vitamin B12 in it – tea. Some types of fermented tea can have more than 1.0 μg per 100 g of dry weight. However, you won’t be drinking this much tea every day!

In short, although fermented foods can add to your daily B12 load, they should not be your primary sources.



Sea vegetables (edible algae)

Additional sources of vitamin B12 for vegans (and raw vegans too!) - raw nori

Raw nori sheets

About half of edible and non-edible algae species require vitamin B12 for growth. As you know, they cannot make it on their own – they have to obtain it from symbiotic B12 bacteria that lives on their surface. That makes sea vegetables potential sources of naturally-occurring vegan B12. Around the world, people eat a lot of sea vegetables, especially those living near coasts. The most widely consumed variety is laver, or nori as it is commonly known. Coincidentally or not, to date, this is the only known sea vegetable that contains bioavailable vitamin B12 in substantial amounts. All other  tested algal species either lack or have small amounts. Still others have B12 analogs of which only some can be converted to bioavailable B12, active analogs they are called. While other analogs cannot be converted to bioavailable B12 – inactive analogs. The bad news is some inactive B12 analogs can interfere with and decrease the overall bioavailable B12 activity in your body.

Okay, there are two types of nori – purple nori and green nori. Purple nori B12 content ranges from 12 to about 140 μg per 100 g. Overall, it contains twice as more vitamin B12 as green nori. For example, a Korean purple nori has 134 μg per 100 g of dry weight. Not bad at all. But that’s in raw dried form. When roasted its content drops considerably – almost by two times. Considering that the average B12 content of purple nori is around 80 μg per 100 g, approximately 4 g of it should give you 2.4 μg of vitamin B12. I think you won’t have any trouble eating this much as nori pressed into sheets tastes great. Somewhat like very delicate dried fish. Personally, I like it just plain. As opposed to other sea vegetables like dulse it does not make your belly feel bloated… which is surely annoying.

On the other note, the level of B12 in microalgae chlorella is relatively high as well however its content extremely varies from manufacturer to manufacturer. The reason is unknown. That’s a game of chance which you don’t want to play. Still though chlorella can be included on top of primary B12 foods.

Other popular sea vegetables like spirulina and nostoc, also known as blue green algae, have high levels of B12 as well, however, the majority of it are inactive B12 analogs which, again, don’t get converted to bioavailable B12. Remember that some inactive B12 analogs have an ability to knock out already-existing bioavailable B12 in your body. This brings up the question if regularly pumping up on blue green algae supplements is a good idea…

So that you know: the above info on nori I took from a 2014 review study compiled by Japanese researchers. They meticulously examined 71 previously-conducted studies dealing with plant sources of B12.


Coming next is mushrooms and plants that are friends with B12-synthesizing bacteria. Soon! Promise.





Main references: 1 2 (image)


  1. Hello There,

    Can you please post an article about fucoidan!?

    • Hello,

      Sorry for being slow in replying.
      Sure I can do it – the next one will be a recipe just because it is almost ready. However, the next one after that I will try to do about fucoidan 🙂

  2. Oh thanx 🙂

    I will wait with passion!

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