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Vitamin B12: Only a vegan problem?

Vitamin B12 deficiency is definitely one of the most discussed nutrition issues – especially when it comes to the vegan diet. There are countless supplements and many misleading information, so it is difficult for the layperson to keep track of it.

As a vegan, you are repeatedly confronted with the general assumption of a vitamin B12 deficiency. And in fact, you should take a preparation with a vegan diet. But does this really only apply to vegans? How do “non-vegans” get enough of it? Should one also supplement vitamin B12 as a “non-vegan”?

What is vitamin B12?

Vitamin B12, in technical language cobalamin, is a water-soluble vitamin that can’t be produced by the human body itself. So we have to ingest it through food to avoid deficiency. The liver can store vitamin B12 for several months or even years, but the best thing to do is to make sure that you get a sufficient and constant supply.

Why does the body need vitamin B12?

The human body needs cobalamin (Vit B12) for some metabolic processes. For example, it is required for the breakdown of specific fatty acids from food and for cardiac function. Other essential functions are blood cell formation and nerve function.

Functional deficiency of vitamin B6, B9 and B12

Vitamin B6, B9 and B12 work synergistically, which means that all three vitamins work together and are mutually dependent on their absorption and metabolism. If you take in enough vitamin B9, but not enough vitamin B12, our body cannot use vitamin B9 correctly because it needs vitamin B12. This is called a functional defect. Accordingly, all three vitamins must be available in sufficient quantities to prevent functional deficiency.

Symptoms and consequences of a vitamin B12 deficiency

  • Exhaustion
  • Loss of vitality
  • Fatigue
  • Shaking hands
  • Paleness
  • Black out
  • Low blood pressure
  • Dizziness
  • Lack of concentration
  • Blurred vision
  • Anemia
  • Weakness of memory
  • Depressive mood
  • Breathlessness
  • Loss of coordination
  • Increased tendency to fall
  • Cramps
  • Tingling skin
  • Hyperpigmentation

What contains vitamin B12?

Animal foods

Cobalamin (Vit B12) is found in almost all animal foods, i.e. in meat, fish, dairy products and eggs. Liver and mussels contain a particularly high amount.


The vitamin is only found in animal food in a significant amount and can be used by our body. However, it is becoming increasingly common to hear that algae (e.g. spirulina) and mushrooms should also be suitable suppliers. That is true, but this is not a “real” vitamin B12, but instead so-called vitamin analogs or pseudo-vitamins.

These are molecules that are very similar in their chemical structure to vitamin B12 but cannot be used by humans. There is even the possibility that these pseudo-vitamins, due to their confusible similarity, occupy important B12 transport molecules in the body and thus block the absorption of the “real” vitamin.

Chlorella seems to be the only known plant source of vitamin B12 at the moment. Nonetheless, as far as we know, there are not enough reliable study results that prove that the vitamin it contains can actually be absorbed and used by the body.

Chlorella seems to be the only plant-based source of Vitamin B12
Chlorella seems to be the only known plant source of vitamin B12 at the moment.

Where do the animals get their vitamin b12 from?

Microorganisms such as bacteria and archaea produce vitamin B12. And it is precisely these microorganisms that have ruminants, such as cattle and sheep, in their rumen. On the other hand, in poultry and pigs, vitamin B12 is added to the feed and thus added.

Microorganisms such as bacteria and archaea produce vitamin B12
Microorganisms such as bacteria and archaea produce vitamin B12

In the past, the soils on which the animals grazed and the feed grew were different than today. In the meantime, tons of pesticides and chemicals are being sprayed and kill not only pests but also “good” bacteria that produce vitamin B12. Moreover, nowadays, vegetable foods are washed much more thoroughly before they are eaten. Soil no longer adheres to a carrot when it ends up in our shopping cart and, therefore, no potential vitamin B12. This prevents that both, the farm animals and us humans, can still get enough vitamin B12 naturally from plants.

Three options

There are three options: Either you eat meat from ruminants, which can produce the vitamin themselves, but are often kept and slaughtered with great suffering. Or you eat meat and animal products from animals whose feed has been fortified with vitamin B12 and other additives and medicines. Or you can take it as a supplement in the form of capsules, drops or similar.

With the latter option, you can firstly control the intake directly and secondly, you can check the quality of the dietary supplement yourself.

Who is at risk for a vitamin B12 deficiency?


As a vegan, you avoid animal products for various reasons. Some do it for ecological reasons, others for ethical or maybe also for health reasons. No matter what the motivation may be, you should always keep an eye on your own health. Almost without exception, a permanent vegan diet without vitamin B12 supplements will sooner or later lead to a deficiency. Therefore, the regular intake of a supplement is essential for every vegan.


As a vegetarian, it depends on the individual diet. How often do you eat eggs? And how often dairy products? To be on the safe side, even as a vegetarian, an occasional test by your family doctor does no harm. If necessary, you can then help with a dietary supplement. Adequate vitamin B12 intake should be ensured, especially during pregnancy and breastfeeding.

People with stomach disorders

The so-called intrinsic factor in the gastric mucosa is necessary for the absorption of vitamin B12. In gastric diseases (e.g. gastrectomy, chronic gastrointestinal inflammation), the formation of this auxiliary can be disturbed. People aged 65 and over are particularly affected. Taking acid blockers (antacids) or gastric protection (proton pump inhibitors) for a long time can also lead to a deficiency.

People with bowel disease

People who suffer from inflammatory bowel diseases such as ulcerative colitis, Crohn’s disease, exocrine pancreatic insufficiency as well as people who have had part of their intestines removed, have an increased risk of a deficiency. Both stomach and intestinal diseases can lead to an undersupply regardless of the vitamin B12 intake.

Reference values ​​for vitamin B12

0 bis~ 0,5
4 bis~ 1,4
1 bis~ 1,5
4 bis~ 2,0
7 bis~ 2,5
10 bis~ 3,5
Adolescents & adults
from 13 years~ 4,0
Pregnant women~ 4,5
Breastfeeding women~ 5,5
Vitamin B12 Schätzwerte der Deutschen Gesellschaft für Ernährung 2019

The German Society for Nutrition (DGE) gives an estimate of 4.0 micrograms per day for adolescents from 13 years and adults. A value of 4.5 micrograms applies to pregnant women and 5.5 micrograms to breastfeeding women. The value is slightly lower for infants and children. (For reading: new reference value DGE)

Supplementation of vitamin B12

Dietary supplements come in countless different forms, compositions and doses, which makes it difficult to keep track of things. That is why we want to help you find the right preparation and first explain the differences.

Four different forms

Vitamin B12 supplements can consist of four different forms. These have different properties, can be used differently by our body and are therefore also suitable in different ways.


Cyanocobalamin is a synthetic (artificial) form of vitamin B12. It is very easy and inexpensive to manufacture and has a long shelf life. However, it cannot be used directly by our body, but must first be converted into the bioactive forms methylcobalamin and adenosylcobalamin. The conversion is not a problem under normal circumstances, but a part of the ingested cyanocobalamin is excreted unused. This slightly reduces the bioavailability, i.e. the proportion of the vitamin actually used.


Methylcobalamin is a natural and bioactive form of vitamin B12. This means that our body can absorb and utilize the substrate directly. Thus, the intake of preparations with methylcobalamin is comparatively better than with cyanocobalamin.


The most common form of cobalamin in our body is adenosylcobalamin. Like methylcobalamin, it is a natural and bioactive form of cobalamin and can be absorbed directly.


Hydroxocobalamin is found in many foods, but it is not a bioactive form. In the body, it must first be converted into the two bioactive forms methylcobalamin and adenosylcobalamin before it can be used. Nevertheless, hydroxocobalamin has one advantage: It binds particularly well to the body’s own transport molecules and therefore stays in the bloodstream longer than the other forms. Due to this so-called depot effect, it is well suited for long-lasting and steady supplies.

The right mix

bioactivebioactivenot bioactivenot bioactive
daily intakedaily intakedepot effectdaily intake
very suitablevery suitablesuitableless suitable
Die vier unterschiedliche Formen von Vitamin B12 Nahrungsergänzungsmitteln

The best supply is obtained by combining the three natural forms: methylcobalamin, adenosylcobalamin and hydroxocobalamin. Some supplements only combine the first two forms, which is also recommended for regular intake.

Capsules, tablets or drops

A common form of supplement is tablets, although these are often not vegan because they contain lactose, gelatin or wool/beeswax. Capsules may also contain gelatin, but usually have fewer additives than tablets.

Vitamin capsules are also frequently seen. One advantage of capsules is that due to the loose shape of the powder. This allows the preparation to bind to the intrinsic factor in the stomach immediately and does not have to be dissolved first, as is the case with tablets. Both ways aim to absorb the vitamin in the intestine.

In addition to the conventional preparations, there are now also drops, sprays and lozenges. The vitamin should get into the bloodstream directly through the oral mucosa.

It is assumed that both routes of absorption – via the intestine and via the oral mucosa – work similarly well. An advantage of the so-called sublingual ingestion (via the oral mucosa) has not yet been found. However, it should be noted that drops, sprays, etc. often contain unnecessary additives.

A quite new form is an enriched toothpaste, which is said to deliver 3 micrograms when brushed twice.


Doses of common vitamin B12 supplements range from 10 micrograms to 5000 micrograms. How can it be that there are such enormous differences? According to the DGE, an adult only needs 4 micrograms a day?

The high doses are due to our ability to absorb the vitamin. Our body cannot absorb 100% of the preparations, so a dose of more than 4 micrograms makes sense. There are two different ways of absorption: active and passive absorption.

Active absorption

The active absorption depends on the so-called intrinsic factor in the gastric mucosa. A maximum of 1.5 to 2 micrograms can be absorbed in the intestine per intake. Therefore, it doesn’t matter whether you consume 10µg or 5000µg, you can actively absorb a maximum of 2 micrograms of it.

Passive absorption

In addition to active absorption, there is also passive absorption by diffusion. These allow larger amounts of vitamin B12 to be absorbed. The body can absorb about 1% of the absorbed dose via diffusion in the intestine.

Total absorption

The actual absorption therefore corresponds to the following:

Absorption = 1,5 microgram + dose/100

Since the food supplements are usually only taken once a day, this results in a recommended dosage of 300 – 400 micrograms per day. With this dosage, an adequate supply is ensured. There are hardly any preparations with this dosage but mostly with 500µg, so one with 500 micrograms should be the best choice for a healthy adult.

Our product recommendations

Good sources of vitamin B6 and B9

As we have already described, the functions of the three B vitamins 6, 9 and 12 depend on each other. Accordingly, an adequate supply of all three vitamins should be ensured. Fortunately, the needs of both vitamin B6 and vitamin B9 can easily be met with some basic foods.

Vitamin B6 (Pyridoxine):

  • Brown rice, whole grains
  • Soybeans, chickpeas, lentils, white beans
  • Potatoes, carrots, broccoli, Brussels sprouts, peppers
  • Avocado, bananas
  • Walnuts, sunflower seeds, peanuts

Vitamin B9 (Folate):

  • Oats
  • Lima beans, chickpeas, soybeans, white beans, lentils, peas
  • Kale, Brussels sprouts, cauliflower, spinach, lamb’s lettuce, broccoli, endive salad, leek

Some vitamin supplements, the so-called vitamin B complexes, contain all B vitamins anyway so that a functional deficiency is automatically prevented.


  • Vitamin B12 belongs to the group of cobalamins
  • It performs some important functions in our body (cell division, blood formation, metabolic processes)
  • Adequate and regular intake is very important
  • Natural sources are animal food from ruminants (cattle and sheep). However, ethical and ecological aspects must be observed.
  • The animal feed of pigs and chickens is mostly enriched with vitamin B12, so pork and eggs are actually not natural sources of vitamin B12
  • Vitamin B12 is sensitive to heat and can be ineffective when cooking
  • Non-vegans should take a test from time to time, for example, every 3 years, with the family doctor and take a dietary supplement if there is an insufficiency/deficiency.
  • Vegans have to supplement vitamin B12, since an adequate supply via plant foods is not possible.

If you are interested in other topics of a healthy, plant-based diet, then have a look at our other blog posts! 😉

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