Vitamin B12 (or cobalamin) is a vitamin that is essential for our health. It serves as a co-factor for enzymes, which means that it must be present for these enzymes to be active. The body uses it for the following functions, among others:
- Formation of red blood cells in the bone marrow.
- Synthesis of DNA.
- Metabolism of fatty acids and amino acids.
- Neurological function (synthesis of myelin sheaths)
Because this essential vitamin is required for all of these processes, symptoms of vitamin B12 deficiency can include, for example, red blood cell disorders. Furthermore, a deficiency can lead to neurological impairments. But these are just a few examples of the multitude of deficiency symptoms.
Foods with vitamin B12 are primarily animal products such as meat, fish, eggs and dairy products, whereas plant foods do not usually contain them. The vitamin is formed by microorganisms which occur in the soil or in water. These B12-producing microbes are then transferred to grazing animals such as cows or taken up in plankton and thus accumulate in fish. However, there are also some foods that are enriched with this vitamin. You can get an overview of these foods in Part 3 of our B12 series.
Vitamin B12 Absorption
The vitamin B12 naturally contained in food is bound to proteins. After it has been ingested with food, it is released from the food by the acidic environment in the stomach and transferred to binding proteins. In the meantime, food supplements and fortified foods contain the vitamin in free form, which does not have to be released by stomach acids. The B12-binding protein complexes are then recognized and absorbed by a section of the small intestine. The B12 bound to the transcobalamin transport protein then enters the bloodstream. It takes about 3-4 hours from the absorption to the releasing in the bloodstream. The absorption mechanism of this vitamin can, therefore, be described as very complex and, in the case of disorders, can contribute to a long-term deficiency.
The body can absorb about half of a dose of 1 µg of this vitamin at a time. The total amount of B12 absorbed increases with higher doses, but the percentage of the amount absorbed decreases with increasing dose. The ability to reabsorb is approximately every 4-6 hours. Too much vitamin B12 is stored in the liver, which can last for a few years. A deficiency, therefore, occurs when this memory is used up and no new vitamin B12 is taken up. In contrast, a vitamin B12 overdose cannot be achieved through food. However, excessive intake of high-dose supplements or, for example, parenteral administration can lead to certain side effects. These side effects mainly include allergic skin reactions or acne-like skin changes, which some people.
Vitamin B12 Levels Measurement
Vitamin B12 is most often checked for a deficiency since symptoms can occur especially with a vegan or vegetarian diet. Low serum levels indicate a deficiency, while high levels are an indicator of adequate care. Values in the middle and low range, a diet adjustment or the intake of nutritional supplements is recommended.
Holo-transcobalamin (Holo-TC) is another marker to check the vitamin B12 supply. Studies show that both measurement methods have similar specificity and sensitivity.
There are many reasons why vitamin B12 level drops. The next article in this series describes the symptoms and causes of vitamin B12 deficiency.
Do you think you could have a deficiency or do you have a vegetarian or vegan diet? Head to your local MD and ask about getting checked.
Read Part Two Here>>