Vitamin B12 (cobalamin) is one of eight water-soluble B vitamins. Vitamin B12 ensures the proper functioning of the hematopoietic and nervous systems. In addition, it plays an important role in numerous metabolic processes occurring in rapidly dividing cells such as skin, blood cells, nerve tissue, and the digestive system. Vitamin B12 is stored in the liver, and its reserves are sufficient for about 5-10 years, which is why the first symptoms of deficiency of this vitamin begin to appear only after several years of inadequate supply. Its unique feature is the presence of a central cobalt atom, which distinguishes it from other vitamins. The human body is unable to synthesize it - it must be supplied with food or in the form of supplements. Vitamin B12 is involved in many biological processes, such as DNA and RNA synthesis; metabolism of proteins, fats, and carbohydrates; and red blood cell formation. It is also a key factor in lowering homocysteine levels, a sulfur-containing amino acid produced during protein breakdown, whose excess is associated with the risk of cardiovascular disease.
The main source of vitamin B12 is meat and meat products. The highest amounts of vitamin B12 are found in liver and kidneys. Therefore, people on vegetarian and vegan diets are usually at risk of deficiency. In the case of a restrictive vegan diet, the only sources of cobalamin are mushrooms, algae, yeast, and fermented products. However, vitamin B12 deficiency is increasingly common not only among people on vegetarian and vegan diets, but also among meat eaters who consume highly processed foods with negligible vitamin content. The foods richest in vitamin B12 include the aforementioned meat and offal (especially liver and kidneys), fish and seafood, eggs, milk, fermented dairy products, as well as yellow cheese and blue cheese. It is worth remembering that many foods today are enriched with vitamin B12, especially plant-based milks and breakfast cereals, but it should be noted that the vitamin added to the product is absorbed by our body in small amounts, so it is much better to ensure a proper diet that includes foods rich in this vitamin.
- Proper production of red blood cells
B12 participates in erythropoiesis—the process of red blood cell formation in the bone marrow. Deficiency leads to megaloblastic anemia, whose symptoms include fatigue, weakness, and reduced exercise capacity.
- Metabolism and energy
B12 participates in the conversion of nutrients into energy, which is important for athletes—it affects recovery and the quality of training.
- Functioning of the nervous system
Cobalamin supports the production of myelin, a protective sheath that covers nerves and ensures efficient signal transmission. Deficiencies can manifest themselves in sensory disturbances, impaired concentration, or numbness in the limbs.
- DNA synthesis and cell division
Vitamin B12 is essential for proper DNA synthesis. It acts as a cofactor in folic acid metabolism, enabling the creation of new cells.
- Supports concentration and cognitive function
Cobalamin affects memory, concentration, information processing speed, and mood stability. Its deficiency can cause low mood, memory impairment, concentration problems, and in extreme cases even symptoms of depression.
The requirement for vitamin B12 depends on age, gender, health, and lifestyle. The average vitamin B12 content in the body of a healthy adult should be 2-3 mg. According to current Polish standards from 2020, the recommended intake of cobalamin for adults is 2.4 μg/day. For pregnant women, it is slightly higher at 2.6 μg/day, and for breastfeeding women at 2.8 μg/day. What level of cobalamin should athletes have?
Research indicates that athletes should have higher optimal vitamin B12 levels than people who do not exercise. An analysis of over 1,100 blood samples from athletes found that: the average concentration of vitamin B12 in active athletes was approximately 739 pg/mL, and an improvement in blood parameters (e.g., hemoglobin) was observed at levels above 400 pg/mL. Therefore, people who are regularly physically active should ensure that their vitamin B12 levels are in the upper range of the normal range in blood tests.
Vitamin B12 - cobalamin is a key vitamin, essential for the proper functioning of our body. It is responsible for the proper production of red blood cells, the functioning of the nervous system, DNA and RNA synthesis, and the metabolism of fats, proteins, and carbohydrates. It also supports concentration and cognitive functions, as well as many other factors that affect our health and mood. Remember to include foods rich in vitamin B12 in your diet, such as meat, fish, eggs, and milk, and if you are deficient, take appropriate supplements tailored to your needs.
- https://www.akademiamedycyny.pl/wp-content/uploads/2016/05/201301_Geriatria_004.pdf
- https://www.mp.pl/pacjent/dieta/zasady/63297,witamina-b12
- https://pubmed.ncbi.nlm.nih.gov/32283824/
Prepared by: Wiktoria Kubicka
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