Vitamin B12 is the largest vitamin in the body. It is used predominantly for DNA metabolism. Deficiency causes problems, including damage to nerves and blood cells. The damage results in symptoms that must be treated to halt the progression of disease. The diagnosis and treatment of medical disorders should be done with the consultation of a physician or another licensed qualified health care professional.
Vitamin B12 Functions and Mechanism
Vitamin B12 is a large water soluble vitamin that is also called cobalamin. It helps red blood cells to form, the nerves to function and the synthesis of DNA. Vitamin B12 binds to enzymes, which are special proteins that help chemical reactions to occur at a rapid rate. The enzymes ultimately help to transfer chemicals called methyl groups, composed of a carbon and three hydrogen atoms, to chemicals such as DNA and RNA, among many others.
Types of Anemia
Anemia means a low red blood cell count. Red blood cells contain the protein hemoglobin, which helps carry oxygen to cells. Anemia can be classified morphologically by the size of the cells. Microcytic anemia means the red blood cell count is low, and the cells are small. Normocytic anemia means the cell count is low and the cells are a normal size. Macrocytic anemia means the cells are few in number and large. This classification helps to narrow the cause of the anemia.
Causes of Pernicious Anemia
Pernicious anemia is a macrocytic anemia, meaning the red blood cells are large in size and few in number. It is most often caused by autoimmune atrophic gastritis. In this condition, the immune system attacks certain cells in the stomach. The stomach normally makes a protein called intrinsic factor that binds to vitamin B12 and is necessary for its absorption in the intestine. In autoimmune atrophic gastritis, the intrinsic factor is not released, and B12 is not absorbed. Inadequate dietary intake, parasite infections in the intestine, surgical removal of the stomach, diseases of the GI tract and bacterial overgrowth are some other causes of B12 deficiency.
Symptoms
Symptoms of vitamin B12 deficiency include fatigue, weakness and pale skin from the anemia. Neurological problems can include difficulty feeling deep touch, sensing one's position in space and walking. It also can cause painful tingling sensations. There may also be gastrointestinal upset.
Treatment
The treatment of anemia from B12 deficiency involves the administration of vitamin B12. Because folate can cause a similar anemia, it is important to distinguish the two causes. If folate is given for a B12 deficiency, it will improve the anemia, but the nerve problems will worsen. In addition, caution should be exercised because low potassium can occur as a result of new red blood cell formation when B12 is given.
References
- "Lehninger Principles of Biochemistry (fourth edition)"; David Nelson and Michael Cox; 2004
- "Robbins and Cotran Pathologic Basis of Disease (eighth edition)"; Vinay Kumar et al; 2009
- "Harrison's Principles of Internal Medicine (17th edition)"; Dr. Anthony Fauci et al; 2008
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