The name vitamin B12 or cobalamin includes several related compounds that act as cofactors in the metabolism of amino acids, fatty acids, phospholipids, hormones and many other substances in the body. The specialty of vitamin B12 is that it contains the mineral cobalt. Foods of animal origin are the most important dietary source of vitamin B12, and too low a dietary intake can cause abnormal blood cell shapes and nerve damage.
Why is it important?
Vitamin B12 has a role in reducing fatigue and exhaustion, but it is also necessary for the normal functioning of the immune and nervous systems, for normal psychological functioning, participates in nutrient metabolism, DNA synthesis and homocysteine metabolism. Vitamin B12 also participates in the process of red blood cell formation, and at the same time plays a very important role in the conversion of reserve and transport forms of folic acid into its effective form.
Vitamin B12 needs
The recommended daily intake (VAT) of vitamin B12 for an adult is 2.5 (g per day. Such an intake is easy to achieve with a mixed varied and balanced diet, but much more difficult with a strict vegetarian diet (veganism), as this vitamin is found mainly in foods of animal origin. Just as an example – you get this amount of vitamin B12 into your body if you eat a burger containing mixed meat (130g) during the day.
Increased needs for this vitamin occur during pregnancy and breastfeeding, as some of it is transferred to the fetus or milk.
Some people, especially older adults and patients with bowel and / or stomach problems, may have difficulty absorbing vitamin B12. For the absorption of the vitamin, the t.i. intrinsic factor, and in its absence, the absorption of vitamin B12 may be impaired. Such people need higher vitamin B12 intakes.
Inputs too low – shortage
Milder forms of vitamin B12 deficiency manifest as fatigue, weakness, constipation, loss of appetite, depression, and impaired memory, while more severe deficiencies manifest themselves as megaloblastic anemia and nervous system disorders. Long-term deficiency and growth deficiency (children, pregnancy) are especially dangerous – the consequences of deficiency in such cases can be irreparable and permanent.
Most people who eat a mixed diet get enough vitamin B12. According to research, adolescents in Europe consume on average several times the recommended daily allowance of vitamin B12. At the same time, the body also has the ability to store certain amounts of B12, and these stores are rarely depleted, so there is no shortage of occasional and limited lower vitamin intakes.
Much more common, however, is a nutritional deficiency of vitamin B12 in people with long-term strict vegetarian diets that contain neither meat nor dairy products and eggs (vegan diet). With such strict vegetarianism, it is necessary to control the intake or. status of vitamin B12, or add this vitamin in the form of dietary supplements or. vitamin fortified foods. Vitamin B12 deficiency is also more common in older adults.
Inputs too high
Where is it located and how effectively is it absorbed?
In terms of chemical composition, vitamin B12 is very complex. Unlike other B vitamins, cobalamin (B12) is synthesized almost exclusively by bacteria in nature. Therefore, it is present only in foods that are bacterially fermented and in foods that come from animals that have received vitamin B12 either from the microbiota in the digestive tract (bacterial origin) or from their diet. Bacteria need sufficient amounts of the trace element cobalt and other appropriate conditions for the biosynthesis of vitamin B12. Interestingly, vitamin B12 is not synthesized by other microorganisms – molds and yeasts. There is also no convincing evidence that vitamin B12 is biosynthesized directly in animal tissues.
By far the most abundant source of vitamin B12 is the liver, but it is also found in the muscle meat of ruminants, fish, eggs, milk and cheese. Foods of plant origin contain practically no vitamin B12 – the minimum amounts come from the biosynthesis of the vitamin by bacteria in the soil, which is accidentally absorbed into plants. Larger amounts of vitamin B12 can be found in foods that are subject to fermentation (including plant), and in those that are enriched with this vitamin during production, e.g. in a variety of fortified cereals for breakfast.
ATTENTION: The human body cannot use some forms of cobalamin!
Due to the increased risk of vitamin B12 deficiency in a strict vegetarian diet, vegans are advised to add this vitamin in the form of dietary supplements. It should be noted that edible blue-green vaccines (cyanobacteria), which mostly contain pseudovitamin B12, which is not active in humans, are sometimes used in vegan supplements. Users should therefore be aware that vitamin B12 is added to dietary supplements in one of the active forms, e.g. such as cyanocobalamin, hydroxycobalamin, methylcobalamin or 5-deoxyadenosylcobalamin.