Vitamin B12 (cobalamin) is a water-soluble vitamin that - just like other vitamins - can not be produced by the body itself, but has to be absorbed by foods such as herring or liver. Vitamin B12 is particularly important for our nervous system, but also has a protective effect on our cardiovascular system. A lack of vitamin B12 is rare in Europe, only vegans who do not eat animal food, are at an increased risk.
This is how vitamin B12 works
Although our body needs only small amounts of vitamin B12, the vitamin is nevertheless involved in many important processes in the organism. For example, it influences cell growth and cell division and is required for the formation of erythrocytes.
In addition, vitamin B12 is also critical to our nervous system as it contributes to the formation of the myelin sheath surrounding the nerve fibers. Also important is vitamin B12 for our brain. Scientists suspect that people with vitamin B12 deficiency have a significantly higher risk of developing dementia later on. Likewise, in these individuals, the likelihood that it will lead to a loss of brain mass, rise.
Finally, vitamin B12 is also said to have a protective effect on the cardiovascular system: it converts the amino acid homocysteine, which can have harmful effects on the heart and circulation, into the harmless amino acid methionine. Through this conversion, vitamin B12 prevents diseases such as arteriosclerosis.
Vitamin B12: Daily need
The daily dose of vitamin B12 is only three micrograms, which is significantly lower than other vitamins. In pregnant women, the need is slightly higher, it is around four micrograms.
The daily requirement for vitamin B12 can be covered, for example, by eating one of the following foods:
- 5 grams of liver
- 25 grams of herring
- 90 grams of salmon
- 100 grams of beef
- 100 grams of salmon
- 150 grams of cheese
- 3 eggs
- 500 milliliters of whole milk
Vitamin B12 deficiency in vegetarians and vegans
Looking at the list of foods that have high levels of vitamin B12, it is clear that vitamin B12 is found only in animal foods in significant quantities.
That's why vegetarians, and especially vegans, have to be careful that there is no vitamin B12 deficiency. If there is a risk of deficiency, you can prevent it by taking vitamin B12 tablets.
In addition to animal foods, very low levels of vitamin B12 are also found in plant foods that are bacterially fermented. For example, sauerkraut belongs to these foods.
Lack of vitamin B12
Since vitamin B12 has a very long half-life, vitamin B12 deficiency develops very slowly. If the supply of vitamin B12 is completely stopped, the body can consume about two to three years from the reserves in the liver, only then makes the deficiency noticeable. In addition to the liver, vitamin B12 is also stored in the brain, heart and skeletal muscles.
The reason for a vitamin B12 deficiency may be, on the one hand, that too little vitamin B12 is supplied to the body via the diet. It is much more common, however, that the ability to absorb in the gastrointestinal tract is disturbed. Vitamins can normally be absorbed directly into the body via the intestine, but vitamin B12 requires a transport protein called the intrinsic factor.
Often, the production of this intrinsic factor is disrupted by the gastric cells in older people, as they are particularly often a gastric mucosal atrophy. In addition, the production of the factor but also by chronic gastritis, drugs such as omeprazole, which inhibit the production of gastric acid, and severe inflammation of the intestine, such as Crohn's disease is adversely affected.
Symptoms of vitamin B12 deficiency
If too little vitamin B12 is ingested, or if the amount present can not be utilized, this can lead to anemia, which in professional circles is also referred to as pernicious anemia. The anemia is accompanied by symptoms such as paleness, difficulty concentrating and tiredness.
In addition, it can also lead to sensory disturbances on the feet and hands in a vitamin B12 deficiency. These abnormalities are due to central nervous system disorders caused by vitamin B12 deficiency. The same applies to occurring memory disorders that can develop to dementia.
Other symptoms that can be caused by a vitamin B12 deficiency are:
- Loss of appetite and weight loss
- Gastrointestinal problems like diarrhea or constipation
- burning tongue
- Increased susceptibility to infection
- Dysfunctions in the spinal cord (funicular myelosis)
Overdose of vitamin B12
An overdose of vitamin B12 is normally not possible because vitamin B12 is water-soluble and excess vitamin B12 is simply excreted via the kidneys.
If vitamin B12 is used for therapeutic purposes and administered via an injection, an overdose is possible, but this usually remains without consequences. Only in rare cases, as a result of overdose may lead to local allergic reactions and acne-like complaints.
Nevertheless, the Federal Institute for Risk Assessment (BfR) recommends that when taking vitamin B12 in the form of dietary supplements, a daily intake of 25 micrograms should not be exceeded.