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Vitamin B12 - Sources, recommended intake, symptoms of deficiency, and reference values

Vitamin B12 – Sources, recommended intake, symptoms of deficiency, and reference values

Vitamin B12, or cobalamin, enables the formation of hereditary factors, boosts metabolism, and ensures the health of the central nervous system.

Vitamin B12

  • Vitamin B12 is needed especially for the functioning of the nervous system.
  • Vitamin B12 enables the formation of hereditary factors.
  • Vitamin B12 is only obtained from food of animal origin, which is why those following a largely plant-based diet should pay attention to sufficient intake of B12.
  • Vitamin B12 deficiency is mainly found in elderly people and vegans.
  • Liver foods are particularly rich in vitamin B12.

What is vitamin B12? 

Vitamin B12 is an important vitamin obtained from animal products. Vitamin B12 protects normal brain function and cell renewal, which means that it also fights ageing in the brain and body.

Vitamin B12 is one of the most important vitamins for humans. It affects the formation of red blood cells, the nervous system and the functioning of the brain. In addition, it is needed for the formation of hereditary factors, or DNA. 

Since vitamin B12 is only found in foods of animal origin, vegetarians and vegans are at a higher risk of B12 deficiency. Heavy alcohol consumption, smoking and nutrient absorption problems can also lead to vitamin deficiency. 

Older people are also more likely to have various kinds of deficiencies, such as vitamin B12 deficiency. Vitamin B12 deficiency can be a serious problem, as it affects, for example, memory functions, cognition, and learning ability. 

What are the functions of vitamin B12 in the body?

Vitamin B12 has many functions in the body. It enables the formation of hereditary factors, boosts metabolism, and ensures the health of the central nervous system.

How does B12 vitamin affect hair, nails, and skin?

B12 helps cells regenerate, which keeps hair, nails, and skin in good condition. Conversely, a deficiency in B12 is a common cause of hair loss. Thin hair or weak nails can be a sign that the B12 vitamin levels in the blood should be checked.

How does B12 vitamin affect memory and learning?

The central nervous system and the brain are able to function properly thanks to vitamin B12. Vitamin B12 deficiency can slow down brain function and may lead to the development of various memory and learning disorders. These issues may become apparent years after the deficiency, so it’s important to consider vitamin intake for brain function at all stages of life.

How does B12 vitamin affect vitality and mood?

Vitality and mood are the primary targets of B12 vitamin’s effects. Severe fatigue may be caused by a deficiency in B12 vitamin.

Vitamin B12 also affects mood, the experience of stress, and nervous system degeneration. A deficiency in B12 vitamin can impair mood.

A sufficient intake of B12 vitamin prevents the development of anemia. Anemia is characterized by too few red blood cells and low hemoglobin levels. It can be a potential cause of experiencing severe fatigue. Iron-deficiency anemia can be treated with iron supplements, but they are not effective if the anemia is due to a deficiency in vitamin B12.

How does vitamin B12 affect digestion?

Taking care of a healthy stomach is advisable because an acid-free stomach can predispose to a deficiency of B12 vitamin. On the other hand, sufficient B12 intake helps to keep digestion healthy.

What are the reference values for vitamin B12? 

The reference levels may vary depending on the laboratory and the test analysis method.

Vitamin B12 deficiency 

Since B12 can be stored in the body to such an extent that it lasts for three to five years, it is not necessary to consume it daily. B12 deficiency can be caused by a poor diet over several years. 

On average, people with a mixed diet obtain much more vitamin B12 than the recommended intake. The body’s reserves are also quite high. For this reason, deficiency does not usually occur if you have a varied diet. 

Deficiency is often associated with a poor diet or a very limited vegetarian diet, especially a poorly planned vegan diet.

What are the symptoms of vitamin B12 deficiency? 

Vitamin B12 deficiency can cause the following symptoms: 

The symptoms felt by the person at a certain moment do not provide a full picture of the harmfulness of B12 deficiency because the state of deficiency is progressive and gradually develops over several years. 

The best way to avoid vitamin B12 deficiency is to ensure adequate intake from food. If vitamin B12 deficiency is suspected, its concentration can be measured by a blood test. 

If the deficiency is severe, a vitamin injection is also an option as it ensures that the vitamin enters the system. Initially, injections are given frequently. Later, an injection every 1–3 months is enough for maintenance. In case of malabsorption, the injection treatment may be lifelong. 

Increased need for vitamin B12 

People with a nutritionally poor diet, malnutrition, excessive alcohol consumption, absorption disorders and a vegan diet are at risk of vitamin B12 deficiency. 

In the following situations, special attention should be paid to a varied diet and adequate intake of vitamin B12: 

High vitamin B12 value 

High levels of vitamin B12 have no practical significance if your health is normal. High vitamin B12 levels can rarely be caused by a disease, such as liver or kidney disease. 

How can I increase my vitamin B12 intake? 

Since vitamin B12 is only found in foods of animal origin, dietary B12 can only be obtained by eating animal products. Vitamin B12 can also be taken as a supplement. Meat, fish, poultry, eggs, and dairy products, such as cheese, contain vitamin B12. 

Vegans can get vitamin B12 from supplements and vitaminised products. 

If you know that you are getting too little vitamin B12 from your diet and you cannot change your diet – for example, if you are on a vegan diet – it is always advisable to take a dietary supplement. 

Which foods are good sources of vitamin B12? 

Vitamin B12 is obtained from animal products. Examples of great sources of vitamin B12 include: 

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All tests

You can add individual tests to the pre-made laboratory packages or design your own set of tests.



This page contains the most frequently asked questions and answers.

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