Vitamin B-12 deficiency can occur when the body needs more vitamin B-12 than it receives from the diet. Alternatively, the condition may occur when the body is unable to use the vitamin B-12 from the diet. A shortage of vitamin B-12 can lead to anemia. Anemia is the insufficient delivery of oxygen by red blood cells from the lungs to the cells of the body. The sooner this anemia is treated, the more favorable the outcome. If you suspect you have this condition, contact your doctor immediately.

Causes

There are many causes of vitamin B-12 deficiency. Some are listed below.

• Removal of part of the small intestine or stomach

• Advancing age

• Long term use of certain acid-reducing stomach medications:

• • H2 blockers

• • Proton pump inhibitors

• Atrophic gastritis (inflammation of the stomach) due to:

• • Iron deficiency anemia

• • Bacterial infection with Helicobacter pylori

• • Chronic alcohol abuse

• • Autoimmunity

• Disorders affecting vitamin absorption:

• • Crohn’s disease

• • Cystic fibrosis

• • Celiac disease

• • Tropical sprue

• • Whipple’s disease

• • Tuberculosis

• • Long-term pancreatitis

• • Pernicious anemia (lack of intrinsic factor)

• • AIDS

• Inadequate intake of vitamin B-12

• • Long-term veganism (non-consumption of animal products) or vegetarianism

• • Breast-fed infants of vegan or vegetarian mothers

• • Poor infant nutrition

• • Inadequate nutrition for a pregnant woman

• • Chronic alcohol abuse

• Stillness of the intestinal contents which can be caused by:

• • Abnormal narrowness of intestines

• • Pockets in intestines

• • Connections between loops of the intestine

• • Blind intestinal loops

• Intestinal blockage which can be caused by:

• • Diabetes mellitus

• • Scleroderma

• • Amyloid

• Inflammation of the intestine due to radiation treatment

• Inability to use vitamin B-12:

• • Lack of a needed enzyme

• • Cancer

• • Malnutrition

• • Nonfunctioning transport protein

• Increased need of vitamin B-12:

• • Hyperthyroidism

• • Tapeworm affliction

• • Other types of anemia

• Over-use of nitrous oxide:

• • Frequent use

• • Extended single use of nitrous oxide (more than six hours)

• Metabolic disorders:

• • Methylmalonic aciduria

• • Homocystinuria

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. The following factors increase your chance of developing vitamin B-12 deficiency. If you have any of these risk factors, tell your doctor:

• Alcoholism

• Use of certain drugs:

• • Biguanides for diabetes

• • Para amino salicylic acid for tuberculosis

• • Calcium-chelating drugs taken by mouth

• • Colchicine

• • Neomycin

• • Cimetidine

• • Cholestyramine

• Age: over 50 years old

• Strict vegetarian diet (vegans)

Symptoms

The symptoms of pernicious anemia can vary from person-to-person. Symptoms may change or worsen over time. If you experience any of these symptoms do not assume it is due to this anemia. These symptoms may be caused by other health conditions. If you experience any one of them, see your physician.

Symptoms can include:

• Sensation of pins and needles in feet or hands

• Alternating constipation and diarrhea

• Stinging sensation on the tongue or smooth red tongue

• Substantial weight loss

• Inability to distinguish the colors yellow and blue

• Tiredness

• Paleness

• Loss of hunger

• Altered sense of taste

• Confusion

• Depression

• Impaired sense of balance, especially in the dark

• Ringing in the ears

• Cracked lips

• Yellow skin

• Fever

• Inability to sense vibrations in feet or legs

• Dizziness when changing to standing position

• Rapid heart rate

Diagnosis

Your doctor will ask about your symptoms and medical history, and perform a physical exam. Tests may include the following:

• Complete Blood Count (CBC)–a count of the number of red and white blood cells in a blood sample

• Vitamin B-12 Level–a test that measures the amount of vitamin B-12 in the blood

• Methylmalonic Acid (MMA) Level–a measurement of the amount of methylmalonic acid in the blood; this test determines whether a vitamin B-12 deficiency exists

• Homocysteine Level–a test that measures the amount of homocysteine in the blood (homocysteine is a building block of protein). The homocysteine level will be elevated if there is a shortage of vitamin B-12, folate, or vitamin B-6.

• Schilling Test–a test in which a harmless amount of radiation is used to assess whether a vitamin B-12 deficiency exists (rarely used)

• Red Blood Cell Folate Level–a measurement of the amount of a B vitamin called folate

• Gastrin Level–a test that may help determine the cause of a vitamin B-12 deficiency

• Intrinsic Factor Assay–a measurement of the amount of a protein called intrinsic factor normally produced in the stomach; this test helps to rule out pernicious anemia as the cause of symptoms

• Bone Marrow Staining–a test that shows whether an iron deficiency exists

Treatment

Talk with your doctor about the best treatment plan for you. Treatment options include the following:

Prevention

To help reduce your chances of developing a deficiency of vitamin B-12, take the following steps:

• Avoid long-term over-consumption of alcohol.

• Take a daily supplement containing vitamin B-12.

• Provide vitamin B-12 to any breastfed baby of a vegan or vegetarian mother.

• Avoid overuse of nitrous oxide.

• Seek diagnosis and treatment of any suspected tapeworm infestation.

• Have your doctor check you for iron deficiency.

• Undergo testing if your doctor suspects you are infected with the bacterium Helicobacter pylori.

• Have your doctor monitor your health closely if you are taking the following drugs:

• • Biguanides

• • Aminosalicylic acid

• • Calcium-chelating drugs taken by mouth

• • Colchicine

• • Neomycin

• • Cimetidine

• • Cholestyramine

RESOURCES:

American Academy of Family Physicians
http://www.aafp.org

MedlinePlus
National Institutes of Health, US National Library of Medicine
http://www.nlm.nih.gov/medlineplus

National Institutes of Health Office of Dietary Supplements
http://ods.od.nih.gov

CANADIAN RESOURCES:

Anemia Institute
http://www.anemiainstitute.org

Healthy Eating and Healthy Aging for Adults
British Columbia Ministry of Health
http://www.bchealthguide.org

References:

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Pernicious anemia. National Institutes of Health, US National Library of Medicine website. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/000569.htm. Accessed January 20, 2007.

Pernicious anemia. National Institutes of Health, US National Library of Medicine website. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/000569.htm. Accessed July 10, 2005.

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