What are the impacts of vitamin B12 deficiency?

Tempo de Leitura: 2 minutos

Vitamin B12 deficiency is a common condition that may present nonspecific clinical characteristics and in severe cases triggers neurological or hematological abnormalities. Although classically caused by pernicious anemia, this condition is now responsible for a minority of cases and B12 deficiency occurs most often due to poor cobalamin absorbed. Since lack of diagnosis can result in potentially serious complications, including spinal cord degeneration, vitamin B12 deficiency should be diagnosed early and treated appropriately.

Vitamin B12 Metabolism

Vitamin B12 is obtained from food sources such as meat, eggs and dairy products. Individuals consume about 2.4 μg of vitamin B12 per day, of which only 50-60% is absorbed. After absorption, large amounts of vitamin B12 stay in the liver. Consequently, any reduction in B12 intake may take 5 to 10 years to manifest clinically. A small proportion of absorption (1-5%) of free vitamin B12 occurs in the intestine by passive diffusion in one, regardless of an intrinsic factor. Thus, the use of intramuscular injections instead of oral formulations for deficiency is justified.

Clinical manifestations of B12 deficiency

Clinical manifestations of vitamin B12 deficiency may be hematological, where high mean corpuscular volume, low hemoglobin, neutropenia, thrombocytopenia, and pancytopenia occur. As well as how Neurological, characterized by subacute peripheral neuropathy combined with bone marrow degeneration and autonomic, e.g. intestinal/urinary incontinence and erectile dysfunction. And such as Alzheimer’s disease, depression, mania, delirium and psychosis.

Clinical practice

Currently, regardless of the underlying cause, patients are treated with intramuscular cobalamin. For those without neurological involvement, the usual is 1 mg every other day for two weeks, followed by quarterly injections of 1 mg. Therefore, it is necessary to administer andregimen is due to diseases such as pernicious anemia. In cases where there are neurological features, the same dose is administered until symptomatic improvement is observed, followed by injections every two months. Finally, gastroenterological investigations are carried out if malabsorption, gastric cancer or celiac disease are suspected.


Study suggestion: The importance of vitamin B12 in health and disease

Watch the video on Science Play with Rodrigo Manda:
Vitamin B12 Metabolism

Article: B12 Deficiency

Shipton MJ, Thachil J. Vitamin B12 deficiency – A 21st century perspective . Clin Med (Lond)

. 2015;15(2):145-150. doi:10.7861/clinmedicine.15-2-145

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