Vitamin B12 has a major influence on our general well-being. The vitamin is involved in vital processes such as blood formation and cell division. Only animal foods such as meat, fish and eggs contain enough vitamin B12 to cover our daily needs. That's why it's especially worthwhile for people who eat a vegetarian or vegan diet to take a closer look here.
In this article, we explain what vitamin B12 actually is, where it can be found, and how you can easily meet your daily needs.
Vitamin B12 - what is it?
Vitamin B12 describes a group of chemical compounds: cobalamins. All vitamins in this group, such as vitamin B2 or vitamin B6, have a similar chemical structure and differ only in subtleties (the so-called side groups).
Vitamin B12 is a nutrient that we must regularly consume through food. Therefore, B12 is one of the essential substances. This means that the body cannot produce enough of it on its own. Other essential substances for the body include minerals and various amino acids.
Vitamin B12 is also a water-soluble vitamin. Unlike vitamin D, for example, it does not require fat to be usable by the body. Vitamin B12, like vitamin C, can be absorbed by the body with the help of water. This is why it is grouped with the water-soluble vitamins.
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Forms of Vitamin B12
If you read methylcobalamin, adenosylcobalamin or hydroxycobalamin in an ingredient list, you will notice that this is Vitamin B12. The suffix "cobalamin" gives it away.
More precisely, these are the bioactive forms of vitamin B12. Bioactive means that the body can utilize them well.
Cyanocobalamin, on the other hand, is less bioactive. The body can utilize it less effectively than the other forms. However, it is cheaper to produce and is therefore found in some dietary supplements and medications.
In summary:
- Bioactive and thus well utilized: Methyl-, adenosyl- and hydroxycobalamins
- Less usable: Cyanocobalamins
How does the body store Vitamin B12?
Vitamin B12 is stored in the body in the liver. This reservoir is relatively large, holding 2 - 5 mg. Our daily requirement, however, is 4 µg. The reserves could supply us with Vit B12 for months, even if our needs are increased due to pregnancy or stress, for example.
In comparison: the body can only store vitamin C for hours to a maximum of weeks. Overall, no other vitamin can be stored in the human body for as long as vitamin B12.
Why does the body need Vitamin B12?
Vitamin B12 contributes to the normal functioning of your
- nervous system,
- immune system and
- energy metabolism
A look at the diversity of these individual areas shows that B12 makes an important contribution to our well-being.
More precisely, cobalamins are necessary for the following bodily functions:
- Formation of red blood cells
- Fatty acid breakdown
- Folic acid metabolism (which is also related to the increased need during pregnancy)
- Homocysteine metabolism (keyword detoxification)
- Synthesis of DNA building blocks and cell division
Vitamin B12 is a real all-rounder and crucial for very different processes.
What is the daily requirement of Vitamin B12?
The daily requirement of vitamin B12 for a healthy person is approximately 4 µg. For pregnant and breastfeeding women, the estimated requirement increases to about 4.5 - 5.5 µg per day. For people with, for example, gastrointestinal diseases, the requirement can be higher. Therefore, we speak of the requirement of a healthy person.
Compared to other nutrients, this is a requirement that is easily met by people who eat a mixed diet. A mixed diet means a diet that includes both animal and plant-based foods.
What foods contain Vitamin B12?
The following foods, for example, contain the daily requirement:
- 60 g pork
- 100 g beef
- 5 g liver
- 25 g herring
- 100 g salmon
- 150 g cheese
- 3 eggs
- 500 ml milk
In animal foods, the concentration of vitamin B12 is comparatively high.
Fermented foods such as beer and sauerkraut, on the other hand, contain only traces of B12. These small amounts do not cover the daily human requirement.
What and how much can I eat to cover my needs?
To cover your daily needs, small portions of the mentioned foods are sufficient. For example, 2 - 3 slices of Emmental or Camembert for breakfast already cover your daily needs. If you consume high-quality meat and fish (preferably organic) 2 - 3 times a week, as well as dairy products daily, you generally don't have to worry about your vitamin B12 supply.
How can a Vitamin B12 deficiency occur?
A vitamin B12 deficiency can have various causes:
- An insufficient vitamin B12 intake through diet.
This primarily affects people who follow a vegan diet. Partially also with a vegetarian diet, if milk and cheese products are eaten only rarely.
- An insufficient physical absorption (i.e. in the intestine) of vitamin B12.
This particularly affects older people, for whom absorption losses in the body of approximately 50% may be responsible.
Medications or diseases of the gastrointestinal tract can also limit or prevent the absorption of vitamin B12. Even if enough vitamin B12 is consumed with food, the body may not be able to utilize it sufficiently and eventually excretes it.
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How does a deficiency manifest itself?
A vitamin B12 deficiency can manifest itself in various physical and psychological ways:
- Concentration difficulties and fatigue
- Anemia, initially manifesting as fatigue, palpitations, and pale skin (Pernicious Anemia)
- Hair loss
- Depressive moods and mood swings
- Weakened immune system
Due to the large depot in the human liver, an insufficient supply of vitamin B12 may only become noticeable after months. This is because the body can draw on its natural reserves.
The body does this when the intake is insufficient or the demand is increased. This can occur, for example, during stress, intense exercise, or also during pregnancy or breastfeeding.
Vitamin B12 and vegetarian diet
Although pork, beef, and fish contain the highest amounts of vitamin B12, a diet without meat and fish can still adequately cover our B12 needs.
As a rule, you don't need to worry about your B12 levels if you have the listed amounts of cheese and dairy products on your plate daily or several times a week.
For example, if you eat a wholemeal bread with 2-3 slices of Emmental and an egg for breakfast, you have already met your B12 requirement for that day.
Vitamin B12 and the vegan diet
As you have now learned, vitamin B12 is only found in animal foods such as meat or eggs in amounts that can cover our daily needs.
If you eat a purely plant-based diet, there is a risk of undersupply. In the long term, this can lead to a deficiency. Especially when the liver's stores are depleted.
It is recommended for people on a vegan diet to have a blood test to determine individual needs. Accordingly, you can counteract an undersupply and a long-term deficiency by taking dietary supplements.
Conclusion
We hope that this article has provided you with added value and that you have learned a lot. Here is a summary of all the important information at a glance for you:
- Vitamin B12 is an essential vitamin.
- We must consume B12 through food.
- Vitamin B12 contributes to the normal functioning of our immune system, our performance, and our nervous system.
- The daily requirement is 4 µg/day.
- Vitamin B12 is only found in the required amounts in animal foods. Those who eat a mixed diet (plant-based and animal-based) usually do not have to worry about their B12 supply.
- Even vegetarians can cover their needs by consuming dairy products and eggs daily.
- For vegans and older people, an uncomplicated check of their vitamin B12 status at the doctor is recommended.
Sources
- Biesalski, H. K.; Grimm, P. & Nowitzki-Grimm, S. (2011). Taschenatlas Ernährung (6. Auflage). Thieme
- Ebermann, R.; Elmadfa I. (2011). Lehrbuch Lebensmittelchemie und Ernährung (2. Auflage). Springer-Verlag
- Horn, Fl. (2009). Biochemie des Menschen. Das Lehrbuch für das Medizinstudium (4. Auflage). Thieme
All our articles are written by nutritionists and checked for content quality by specialist experts.
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