Vitamin B12 helps in red blood cell formation, production of DNA, and function of the nervous system.
Vitamin B12 deficiency can occur when the body needs more vitamin B12 than it receives from the diet. Alternatively, the condition may occur when the body is unable to use the vitamin B12 from the diet. A shortage of vitamin B12 can lead to
. Anemia occurs when levels of red blood cells are abnormally low and there is insufficient delivery of oxygen by red blood cells from the lungs to the cells of the body.
Red Blood Cells
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There are many causes of vitamin B12 deficiency. Some are listed below. Removal of part of the small intestine or stomachIncreased age and inadequate absorption of B12
Long-term use of certain acid-reducing stomach medications:
H2 blockersProton pump inhibitors
(inflammation of the stomach) due to:
Iron deficiency anemia
Chronic alcohol abuse
Disorders affecting vitamin absorption:
Crohn’s diseaseCeliac diseaseWhipple’s disease
pancreatitisPernicious anemia—lack of intrinsic factor
Inadequate intake of vitamin B12
Long-term veganism (nonconsumption of animal products) or vegetarianismBreastfed infants of vegan or vegetarian mothersPoor nutritionInadequate nutrition for a pregnant womanChronic alcohol abuseChronic intestinal conditions that lead to malabsorption
Inflammation of the intestine due to
Increased need of vitamin B12:
HyperthyroidismIntestinal parasitesOther types of anemia
The following factors increase your chance of developing vitamin B12 deficiency: Alcoholism
Use of certain drugs:
Biguanides for diabetesCimetidineAcid-reducing medicationsStrict vegan or vegetarian diet
The symptoms of pernicious anemia can vary from person-to-person. Symptoms may change or worsen over time.
Symptoms can include: Sensation of pins and needles in feet or handsStinging sensation on the tongue or smooth red tongueSubstantial weight lossTirednessPalenessAltered sense of tasteConfusionDepressionImpaired sense of balance, especially in the darkInability to sense vibrations in feet or legsLightheadedness when changing to standing positionRapid heart rate
You will be asked about your symptoms and medical history. A physical exam will be done. Tests may include the following: Complete blood count (CBC)—a count of the number of red and white blood cells in a blood sampleVitamin B12 level—a test that measures the amount of vitamin B12 in the bloodMethylmalonic acid (MMA) levelHomocysteine levelSchilling test—a test in which a small amount of radiation is used to assess the absorption of vitamin B12 deficiency Folate level—a measurement of the amount of a B vitamin called folic acidIntrinsic factor antibodies—this test helps to determine pernicious anemia as the cause of symptoms
Talk with your doctor about the best treatment plan for you.
options include the following:
This treatment consists of high doses of an oral vitamin B12 supplement.
The doctor may advise the patient to receive injections of vitamin B12 into a muscle. Injections of vitamin B12 may be given frequently at first. When blood tests show improvement, the doctor may give injections on a monthly basis.
This type of medication may be needed in cases where bacterial overgrowth in the intestines exists. The bacteria compete with the body to absorb the vitamin B12 in the intestines.
The doctor gives the patient a supplement of vitamin B12 that is placed in the nose.
To help reduce your chances of developing a deficiency of vitamin B12, take the following steps: Avoid long-term over-consumption of alcohol.
As directed by your doctor, take a daily supplement containing vitamin B12.
As directed by your doctor, give vitamin B12 to your breastfed baby if you are a vegan or vegetarian.
Undergo testing if your doctor suspects you have a bacterial infection.
Have your doctor monitor your health closely if you are taking certain medications:
Pernicious anemia. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed. Updated August 9, 2013. Accessed December 17, 2013.
Vitamin B12. American Association of Clinical Chemistry website. Available at:
http://www.labtestsonline.org/understanding/analytes/vitamin_b12/glance.html. Updated November 15, 2011. Accessed December 17, 2013.
Vitamin B12. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated July 5, 2013. Accessed December 17, 2013.
Vitamin B12 deficiency. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated November 5, 2013. Accessed December 17, 2013.
Last reviewed December 2013 by Peter Lucas, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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