Vitamin B12 is an essential water-soluble vitamin that is naturally present only in foods of animal origin and must be ingested through food or by using products containing vitamin B12.
This vitamin is a cofactor of two important enzymes essential for anabolic and catabolic processes in the body and plays a key role in the synthesis of DNA, lipids, and proteins, in cell division, the formation of formation of red blood cells, and in the myelination of nerve cells.
Vitamin B12 is also essential for maintaining normal levels of homocysteine in the blood, and thus the structure and function of the nervous system, particularly for maintaining cognitive functions (such as concentration, learning, memory, reasoning), reducing the risk of their decline with aging and the occurrence of Alzheimer’s disease, Parkinson’s disease, and dementia. Normal levels of homocysteine are also associated with a lower risk of cardiovascular and neurovascular diseases, impaired kidney function, and a possible reduced risk of cancer.
In recent years, particular attention has been given to studying its role as an immunomodulator of cellular immunity, primarily by increasing the number of CD8+ or NK cells, which are important for destroying cancer cells.
In general, vitamin B12 is essential for growth and maintenance of the body’s health throughout all stages of life.
Low levels of vitamin B12 during pregnancy are associated with an increased risk of neural tube defects. Certain population groups with specific lifestyles, such as vegans and vegetarians, are at risk of vitamin B12 deficiency due to the absence of vitamin B12 in their diet. 10-30% of the elderly, as well as people with certain diseases, have reduced absorption of vitamin B12. For these population groups, vitamin B12 supplementation is recommended for better overall health.
Recent studies suggest potential beneficial effects of vitamin B12 supplementation in SARS-CoV-2 infection. Vitamin B12 levels are associated with the severity of symptoms of SARS-CoV-2 infection, through the following studied mechanisms: reduction of oxidative stress, improvement of circulation (by reducing homocysteine levels, which impairs microcirculation in the cardiovascular system, nervous system, and kidneys), and anti-inflammatory effects.