Vitamin B12 daily requirement: the most important questions and answers

Vitamin B12 Tagesbedarf: Die wichtigsten Fragen und Antworten

The human body relies on a variety of nutrients to keep itself healthy. It is particularly important to ensure that you get enough vitamins every day so that you can be fit and energetic every day. Vitamin B12 plays a particularly important role here, among many other vitamins.

In this article we will show you what the important vitamin B12 is and what functions it fulfills in the human body. We will explain to you what happens if you have a vitamin deficiency and you will also find out how you can easily cover your daily vitamin B12 requirement.

the essentials in brief

  • Vitamin B12 fulfills many important tasks in our body. Sufficient memory is particularly important for the smooth activity of your mental and physical processes.
  • It is particularly important that you are aware of your daily vitamin B12 requirements and that you adapt your intake to your individual sensitivities and circumstances.
  • Vitamin B12 can be ingested directly through diet or by taking supplements. The dosage of the vitamin should be adjusted to the personal daily requirement.

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What is vitamin B12?

Vitamin B12 is a water-soluble vitamin and belongs to the group of B vitamins. Basically, vitamin B12 is not a single building block, but a group of vitamins that are also called cobalamins. (2)

The vitamin has a significant impact on a wide range of bodily processes, particularly physical performance.

The vital vitamin is produced by so-called microorganisms that occur in the digestive tract or on the surface of unwashed food. Microorganisms are small creatures such as bacteria that can only be seen under a microscope. (9)

What is the role of vitamin B12 in our body?

Vitamin B12 plays a very important role in our body and organism. It protects myelin, the substance that insulates our nerve cells. One of the most important tasks is therefore the maintenance of normal mental and neurological functions.

The following bullet points summarize the important tasks of the vitamin for our organism:

Vitamin B12

  • is involved in cell division and differentiation
  • helps build nerve cells in the spinal cord
  • is involved in reactions in protein and nucleic acid metabolism
  • contributes to the normal functioning of the nervous system: The vitamin is a real brain food - it helps to strengthen your nerves and promote concentration
  • plays an important role in the formation of red blood cells
  • affects muscle function
  • contributes to a normal homocysteine ​​metabolism
  • keeps the energy metabolism in balance (12)

How does the absorption of vitamin B12 work in the organism?

For absorption in our body, vitamin B12 or cobalamin must be actively channeled into the body through the mucous membrane cells in the intestine. In order for absorption to be successful, a special protein is also required, the so-called intrinsic factor. This factor is produced by the gastric mucosa and enters the intestines with the food. (3)

A vitamin B12 store that has been replenished once is sufficient for adults for several years.

The vital vitamin is stored in the liver. However, since our organism also excretes vitamin B12 every day, we are still dependent on a daily intake to ensure sufficient storage.

How does a vitamin B12 deficiency develop?

A vitamin B12 deficiency can occur if the vitamin has not been absorbed by the organism for several years. This can be due, for example, to insufficient intake through food. In addition, certain medications or diseases can also trigger a vitamin B12 deficiency, such as chronic kidney or liver diseases.

It is important to differentiate between the external intake and the actual intake of the body. It is possible that although sufficient vitamin B12 is supplied through diet or supplementation, the body cannot absorb the vitamin. This can be related to a disorder of the intestines, which do not absorb the important vitamin. The reason for this can be, for example, a chronic inflammatory bowel disease. (3)

Reasons for the development of a vitamin B12 deficiency:

  • nutritional deficiency
  • Inadequate intake of vitamin B12
  • Disruption of vitamin B12 absorption
  • Disruption of vitamin B12 utilization
  • Loss and increased consumption of vitamin B12
  • intestinal diseases
  • Medicines(4)

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How does a vitamin B12 deficiency show up?

A lack of vitamin B12 is not uncommon in today's society. A persistent undersupply must be compensated for, otherwise there is a risk of a change in the blood count.(2) In the worst case, this can lead to diseases such as pernicious anemia or even to psychoses. (1)

The vitamin is not excreted in the digestive process, but is always retrieved. However, the symptoms of a deficiency should not be underestimated. In addition to the changes in blood count mentioned above, a deficiency can also cause other physical and mental limitations.(7)

The following is a list of the possible mental and physical problems that a vitamin B12 deficiency can cause:

  • hair loss
  • poor memory
  • fatigue
  • difficulty concentrating
  • depression
  • asthma
  • cramps
  • tingling and numbness
  • Disorders of deep sensitivity up to paralysis
  • Disorders of cell division in skin and mucous membranes
  • muscle weakness
  • Headache migraine
  • Degeneration of the optic nerve
  • Food intolerances, allergies
  • In infants: developmental disabilities(7)

What is a vitamin B12 overdose?

According to studies, an overdose of vitamin B12 is hardly possible. What the body does not need is absorbed through the intestinal wall. However, if an overdose of the vitamin occurs, the body can excrete it through the kidneys.

Man reaches for sushi

Adequate vitamin B12 supply is very important for your organism. You can secure your daily supply in the form of an animal diet or by taking supplements. It is important to know your daily dose and to adjust the intake accordingly. (Image source: Kate Hliznizova /Unsplash)

What role does the daily dose of vitamin B12 play?

What does "recommended daily requirement" mean?

The recommended daily requirement describes the amount of vitamin B12 that the human body should consume and absorb over the course of a day.

According to the recommendations of the German Society for Nutrition, the Daily Recommended Allowance, the EU, the USA and the WHO, the average daily requirement should cover the needs of 97.5 percent of all healthy people. (5,8,10,11)

An average daily requirement is the recommended amount needed to prevent deficiency symptoms. It is basically about the needs of healthy people. Stress, illness, poor diet, smoking, alcohol consumption, medication and gastrointestinal problems are not taken into account.(5,8)

The daily requirement of vitamin B12 is a value that cannot be determined scientifically and must therefore be determined from various factors.

This explains why slightly different values ​​for the daily requirement of vitamin B12 are given internationally.

What is the recommended requirement for vitamin B12?

The recommended daily allowance for vitamin B12 has been evaluated by the organizations mentioned above. The following table shows the dose of vitamin B12 in different phases of life and the recommendations of different countries.

Adults (over 14 years) 3.0 2.5 2.4 2.4
Pregnant women 3.5 - 2.6 2.6
breastfeeding women 4.0 - 2.8 2.8
Children 1-4 1.0 - 0.9 0.9
children 4-7 1.5 - 1.2 1.2
children 7-10 1.8 - 1.8 1.8
Children 10-13 2.0 - 1.8 1.8

Source: German Society for Nutrition.

The table shows that children generally have a low vitamin B12 requirement. The amount of vitamin B12 required increases with age, until it reaches a daily recommended unit of 3 µg in adulthood. A slightly higher daily dose of up to 4 µg is recommended for pregnant and breastfeeding women.(5,8,10,11)

Depending on the phase of life you or the child is in, the intake of vitamin B12 should be adjusted.

How is the vitamin B12 daily requirement determined?

The daily requirement of vitamin B12 is made up of different factors. The average need is calculated considering these factors. These factors are about

  • the amount of vitamin B12 excreted daily
  • the size of the body stores
  • the analysis of nutritional studies

Overall, the average human body stores about 2500 µg of vitamin B12. The body excretes 1-2 µg of it every day. This value of vitamin B12 is lost through excretion. The body needs to be supplied with around 0.5-1 µg of vitamin B12 per day. However, since the organism is constantly losing vitamin B12 and in order to include critical phases, the recommended daily requirement was increased to an average of 1-3 µg.(5,8)

What is my daily requirement of vitamin B-12?

The amount of 1-3 µg of vitamin B12 recommended by the DGE, UNO and EU should generally be sufficient to cover the daily requirement. It is therefore advisable to stick to the values ​​listed to ensure the full functionality of your organism.

More recent studies increasingly emphasize the importance of the vitamin and therefore recommend a slightly increased daily requirement of vitamin B12. According to them, the minimum intake is 7 µg. Such an increased need may exist under the following circumstances:

  • Stress (physical, mental or emotional)
  • heavy physical exertion (including sports)
  • Use of tobacco, alcohol, coffee
  • Consumption of junk food and soft drinks
  • taking medication
  • Disorders of the gastric and intestinal mucosa
  • after long malnutrition (5,8,10,11)

Since today's society is exposed to many of these circumstances and stresses, an increase in the daily dose of vitamin B12 is quite justified.

What options are there to cover my vitamin B12 daily requirement?

In order to avoid the negative consequences of a vitamin B12 deficiency, it is important to ensure that you have an adequate daily intake. Bacteria in the large intestine are able to produce the vitamin themselves, but not in sufficient quantities.

The vitamin cannot be absorbed in the intestine and is therefore not available to the human body. For this reason we are dependent on an external supply of vitamin B12. This can be in the form of food or a dietary supplement.

How can I cover my daily requirement with food?

Vitamin B12 can be found in animal foods such as liver, muscle meat, fish and eggs. It is usually administered to animals via feed enriched with vitamin B12, and humans can subsequently absorb it by consuming animal products. (3)

Animal foods with a particularly high proportion of vitamin B12 at a glance:

  • Beef liver/veal liver: 65 µg
  • Oysters: 14.5 mcg
  • Rabbit: 10 mcg
  • Herring: 8.5 mcg
  • Trout: 4.5 mcg
  • Beef: 5 mcg
  • Pork: 2 mcg
  • Camembert: 3 µg
  • Emmental: 3.1 µg
  • Chicken egg: 1.8 mcg

Traditional medicine assumes that vitamin B12 cannot be found in plant foods. However, this is not entirely true. Studies show that small amounts of vitamin B12 are present in barley grass juice, for example, or in certain microalgae such as chlorella. Very small amounts of vitamin B12 may also be found in fermented foods such as sauerkraut, lactic acidified vegetables, or fermented soy products.(9)

Plant-based foods with a particularly high proportion of vitamin B12 at a glance:

  • nori algae
  • Chlorella
  • barley grass juice
  • sauerkraut
  • sushi
  • Fortified soy milk
  • Soy Products: Tempeh (9)

Although new studies show a small proportion of vitamin B12 in plant-based foods, these are not sufficient to ensure a holistic supply and thus to meet the daily requirement.

You can ensure adequate vitamin B12 intake through animal and partially through plant foods. In the case of a vegan or vegetarian diet, however, it is advisable to cover the required daily requirement with supplements. (Image source: Louis Hansel /Unsplash)

How can I cover my daily requirement with a vegetarian and vegan diet?

Since vitamin B12 is mainly found in animal foods, it is particularly difficult and unlikely for vegetarians and vegans to meet their daily requirements through food. Vegans in particular are therefore dependent on taking vitamin B12 preparations in the form of a supplement. (6)

Vitamin B12 intake in supplement form is recommended by various health associations and organizations, including the International Vegan Society.(5)

When taking supplements, care should be taken to ensure that they are not fortified and are 100% vegan.

What dosage is recommended for taking vitamin B12 supplements?

With a vegan or vegetarian diet, however, an intake of vitamin B12 through a supplement is essential. Irrespective of this, nowadays many other people are also dependent on an additional supply of vitamin B12. When supplementing, it should be noted that the frequency of intake is adapted to the dosage.

The following table shows the recommended dose of vitamin B12 depending on the frequency of intake:

  • 1 mcg: 2-3 times daily
  • 10 mcg: 1-2 times daily
  • 100 mcg: 1 time per day
  • 250 mcg: 5-7 times per week
  • 500 mcg: 3-4 times a week
  • 1000 mcg: 2 times per week (10)


In summary, it can be said that an adequate intake of vitamin B12 is particularly important for your body. A deficiency has many negative consequences, which is why you should definitely make sure you have an adequate supply.

We would like to advise you to have your vitamin B12 level checked if necessary and to ensure your vitamin supply through food or fortified preparations.


  1. A vitamin B12 deficiency can trigger megaloblastic anemia and demyelinating disease.
  2. Vitamin B12 deficiency is a global and widespread problem in today's society.
  3. Vitamin B12 can be absorbed through animal foods. However, there is a difference in the amount present and the actual absorption capacity of the body.
  4. The intake of vitamin B12 must be secured through food. The production of vitamin B12 in the body is not sufficient. A deficiency has many consequences, such as coronary heart disease.
  5. The table of the German Society for Nutrition shows the recommended daily reference of vitamin B12 in different phases of life.
  6. With a vegan and vegetarian diet, a sufficient supply of vitamin B12 can be ensured through supplements. With such a diet, a deficiency often occurs.
  7. A vitamin B12 deficiency has many negative effects on people, both mentally and physically.
  8. The table shows the recommended daily dose of vitamin B12.
  9. Vitamin B12 can also be found in all plant-based foods.
  10. The following studies and results show the WHO recommended daily doses of vitamin B12.
  11. The studies and articles show the US guidelines for taking vitamin B12.
  12. The negative consequences of vitamin B12 as well as the many tasks for the human body are listed in the article.
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