Vitamin B12 is essential for DNA synthesis, and is required for red blood cell and neurological function. While there is no reason to take B12 "for" your liver, your liver is important in vitamin B12 homeostasis, as it is your body's largest storehouse of the vitamin. B12 deficiency can lead to serious disease, and can be treated with either of oral B12 ingestion or B12 shots.
About B12
According to the Office of Dietary Supplements, Vitamin B12 is one of the water-soluble B-complex vitamins which is needed as a cofactor in biochemical reactions that drive red blood cell production and appropriate neurological function. B12 is found naturally in animal products, and is added as a supplement to most breakfast cereals.
About the Liver
According to Barrett and colleagues in "Gangong's Review of Medical Physiology," the liver is the largest gland in the body and is responsible for a wide variety of functions, including synthesis of proteins responsible for clotting and inflammation found in your blood, excretion of toxic metabolites from your blood, and blood glucose regulation. It is found in the upper right quadrant of your abdomen, underneath your rib cage.
B12 and the Liver
In contrast to most of the other water-soluble vitamins, which if consumed in excess are simply excreted in your urine, extra vitamin B12 is stored in your liver. According to Kenneth Kaushansky and Thomas J. Kipps in "Goodman and Gilman's Pharmacology," your daily requirement of vitamin B12 is so low, relative to the amount of B12 stored in your liver, that vitamin B12 deficiency can take years to develop.
B12 deficiency
Vitamin B12 deficiency causes two clinically-relevant diseases. First, because red blood cell production is impaired, anemia can result. Vitamin B12 anemia is typically recognized on a red blood cell analysis as anemia characterized by cells of abnormally large mean volume. According to Charles A. Linker, and Lloyd E. Damon in "Current Medical Diagnosis and Treatment," B12 anemias can result in increased heart rate, shortness of breath, pallor, and weakness. B12 deficiency can also lead to neurologic dysfunction, marked by numbness and tingling of the hands and feet, unsteadiness, and confusion.
Treatment of B12 Deficiency
Treatment of B12 deficiency depends on the cause of the deficiency. If you are B12-deficient because of diet --- for example, as can occur in strict vegans who do not take vitamin supplements --- treatment involves taking B12 supplements. If you are B12 deficient as a result of destruction of a certain type of cell in your stomach which is required for B12 absorption --- a disease known as pernicious anemia --- treatment will involve B12 shots.
References
- Office of Dietary Supplements: Vitamin B12
- "Goodman & Gilman's The Pharmacological Basis of Therapeutics"; Laurence L. Brunton (editor); 2006
- "Ganong's Review of Medical Physiology"; Kim E. Barrett, Susan M. Barman, Scott Boitano; 2010
- "CURRENT Medical Diagnosis & Treatment"; Stephen J. McPhee, Maxine A. Papadakis (editors); 2009
