Basic knowledge Vitamin B12: An essential nutrient for health

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a central role in cellular metabolism. It is essential for DNA synthesis, red blood cell production, and the maintenance of the nervous system. Vitamin B12 deficiency can cause serious health problems, so understanding its function and sources is of great importance.

Chemical structure and function

Vitamin B12 is the largest and most complex of all vitamins. It contains a cobalt ion bound in a corrin ring. The four main forms of vitamin B12 found in the human body are:

• Methylcobalamin
• Adenosylcobalamin
• Hydroxocobalamin
• Cyanocobalamin

Methylcobalamin and adenosylcobalamin are the active coenzyme forms involved in important biochemical reactions.

Methylcobalamin is a coenzyme of methionine synthase involved in the conversion of homocysteine ​​to methionine, an essential amino acid required for DNA methylation and protein synthesis. An increased level of homocysteine ​​in the blood, caused by a deficiency of vitamin B12, is a risk factor for cardiovascular disease.

Adenosylcobalamin acts as a coenzyme of methylmalonyl-CoA mutase, which catalyzes the conversion of methylmalonyl-CoA to succinyl-CoA, an important step in energy metabolism and the synthesis of fatty acids and amino acids.

Vitamin B12 deficiency and its effects

A vitamin B12 deficiency can be caused by various factors, including insufficient dietary intake, impaired absorption or increased need. Risk groups include vegetarians and vegans, the elderly and people with certain gastrointestinal disorders such as Crohn's disease or pernicious anemia.

Clinical manifestations of vitamin B12 deficiency include:

1. Hematological symptoms: Megaloblastic anemia, characterized by the production of abnormally large and immature red blood cells. Symptoms may include fatigue, pallor and shortness of breath.
   
   
2. Neurological symptoms: Neuropathy, which may manifest as numbness, tingling in the extremities, balance disorders and cognitive impairment. In severe cases, subacute combined degeneration of the spinal cord may occur.
   
   
3. Psychiatric symptoms: depression, memory impairment and, in severe cases, dementia.

Diagnosis and therapy
Vitamin B12 deficiency is diagnosed by measuring serum vitamin B12 levels, homocysteine ​​and methylmalonic acid levels. Elevated homocysteine ​​and methylmalonic acid levels are sensitive markers for vitamin B12 deficiency.

Treatment is by oral or intramuscular supplementation of vitamin B12. In cases of absorption disorders, such as pernicious anemia, intramuscular injections are preferred. The dosage and duration of therapy depend on the severity of the deficiency and the underlying cause.

Food sources and prevention
Vitamin B12 occurs naturally in animal products, including meat, fish, eggs and dairy products. Since plant-based foods contain little vitamin B12, vegetarians and vegans should rely on fortified foods or supplements.

The recommended daily dose for adults is about 2.4 micrograms. Pregnant and breastfeeding women have an increased need and should adjust their intake accordingly.

Summary

Vitamin B12 is a vital nutrient that performs numerous physiological functions. Deficiency can have serious hematological, neurological and psychiatric consequences. A balanced diet or appropriate supplementation can prevent vitamin B12 deficiency, contributing to better overall health and quality of life. Awareness of the importance of vitamin B12 and the risk factors for deficiency is crucial to take preventive measures and promote health.