Vitamin B12 Cyanocobalamin

Vitamin B12 (Cyanocobalamin)

Vitamin B12 serves as a cofactor for enzymes involved in the normal function of the nervous system, the formation of red blood cells and for the metabolism of folate. It is also involved in energy production. Together with folate and vitamin B6, vitamin B12 is required for maintenance of normal blood homocysteine levels. Raised homocysteine is a risk factor for cardiovascular disease.

Deficiency

Dietary deficiency is rare in younger people and only occurs among strict vegans. It is more common in older people as a result of impaired absorption, usually due to chronic inflammation of the stomach lining (atrophic gastritis) or lack of intrinsic factor (the substance required for vitamin B12absorption). Deficiency results in the development of pernicious anaemia, in which red blood cells are enlarged (megaloblastic), and peripheral neurological damage develops.

Toxicity

There are few reports of any adverse effects of high intakes of vitamin B12.

Food sources

Vitamin B12 is found in almost all foods of animal origin. Green plants provide none but it can be synthesized by some algae and bacteria, although the bioavailability of such forms has been disputed. Meat, fish, milk, cheese, eggs, yeast extract and fortified breakfast cereals are all dietary sources.

Recent Posts

  • Respiratory Diseases

TYPES OF SPECIFIC PNEUMONIAS

Staphylococcal Pneumonia It may be a primary respiratory infection or secondary to staphylococcal focus anywhere in the body. It is…

2 months ago
  • Respiratory Diseases

ACUTE LOBAR PNEUMONIA

It is the commonest of all specific pneumonias. AETIOLOGY Predisposing causes Age: All ages but 50% of cases are below…

2 months ago
  • Respiratory Diseases

BRONCHIAL ASTHMA

BRONCHIAL ASTHMA DEFINITION OF BRONCHIAL ASTHMA BRONCHIAL ASTHMA is a chronic reversible inflammatory destructive disease of the airways characterised by…

2 months ago
  • Respiratory Diseases

BRONCHIECTASIS

BRONCHIECTASIS DEFINITION BRONCHIECTASIS is a condition of permanent abnormal dilatation of the larger bronchi. AETIOLOGY AND PATHOGENESIS Acquire Obstruction Obstruction…

2 months ago
  • Respiratory Diseases

CHRONIC BRONCHITIS

CHRONIC BRONCHITIS DEFINITION OF CHRONIC BRONCHITIS Chronic bronchitis may be defined as a disease characterised by cough and sputum for…

2 months ago
  • Respiratory Diseases

ACUTE TRACHEO BRONCHITIS

ACUTE TRACHEO BRONCHITIS DEFINITION ACUTE TRACHEO BRONCHITIS is Acute inflammation of Tracheo bronchial tree caused by various organisms (bacteria and…

2 months ago