Vitamin B12 Deficiency Anemia

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Vitamin B12 Deficiency Anemia

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What is vitamin B12 deficiency anemia?

Picture of red blood cells

Having vitamin B12 deficiency means that your body does not have enough of this vitamin. You need B12 to make red blood cells, which carry oxygen through your body. Not having enough B12 can lead to anemia, which means your body does not have enough red blood cells to do the job. This can make you feel weak and tired.

What causes vitamin B12 deficiency anemia?

Most people get more than enough B12 from eating meat, eggs, milk, and cheese. Normally, the vitamin is absorbed by your digestive system—your stomach and intestines. Vitamin B12 deficiency anemia usually happens when the digestive system is not able to absorb the vitamin. This can happen if:

  • You have pernicious anemia. In this anemia, your body destroys the cells in your stomach that help you absorb vitamin B12.
  • You have had surgery to remove part of the stomach or the last part of your small intestine, called the ileum. This includes some types of surgery used to help very overweight people lose weight.
  • You have problems with the way your body digests food, such as sprue (also called celiac disease), Crohn's disease, bacteria growth in the small intestine, or a parasite.

This anemia can also happen if you don't eat enough foods with B12, but this is rare. People who eat a vegan diet and older adults who don't eat a variety of foods may need to take a daily vitamin pill to get enough B12.

What are the symptoms?

If your vitamin B12 deficiency is mild, you may not have symptoms or you may not notice them. Some people may think they are just the result of growing older. As the anemia gets worse, you may:

  • Feel weak, tired, and light-headed.
  • Have pale skin.
  • Have a sore, red tongue or bleeding gums.
  • Feel sick to your stomach and lose weight.
  • Have diarrhea or constipation.

If the level of vitamin B12 stays low for a long time, it can damage your nerve cells. If this happens, you may have:

  • Numbness or tingling in your fingers and toes.
  • A poor sense of balance.
  • Depression.
  • Dementia, a loss of mental abilities.

How is vitamin B12 deficiency anemia diagnosed?

Your doctor will examine you and ask questions about your past health and how you are feeling now. You will also have blood tests to check the number of red blood cells and to see if your body has enough vitamin B12.

The level of folic acid, another B vitamin, will be checked too. Some people whose vitamin B12 levels are too low also have low levels of folic acid. The two problems can cause similar symptoms. But they are treated differently.

How is it treated?

Vitamin B12 deficiency anemia is treated with supplements of vitamin B12. Taking supplements brings your level of vitamin B12 back to normal, so you do not have symptoms. To keep your level of vitamin B12 normal, you will probably need to take supplements for the rest of your life. If you stop taking them, you'll get anemia again.

Your vitamin B12 supplements might be pills or shots. If you use shots, you can learn to give them to yourself at home. For many people, pills work just as well as shots. They also cost less and are easier to take. If you have been getting shots, ask your doctor if you can switch to pills.

You can take steps at home to improve your health by eating a varied diet that includes meat, milk, cheese, and eggs, which are good sources of vitamin B12. Also, eat plenty of foods that contain folic acid, another type of B vitamin. These include leafy green vegetables, citrus fruits, and fortified breads and cereals.

Can vitamin B12 deficiency anemia be prevented?

Most people can prevent this anemia by including animal products like milk, cheese, and eggs in their diets. People who follow a vegan diet can prevent it by taking a daily vitamin pill or by eating foods that have been fortified with B12.

Babies born to women who eat a vegan diet should be checked by a doctor to see whether they need extra vitamin B12.

If you have a high risk of getting this type of anemia, your doctor can give you vitamin B12 shots or pills to prevent it..

Other Places To Get Help

Organizations

Canada's Food Guide
Health Canada, Health Products and Food Branch, Office of Nutrition Policy and Promotion
Web Address: www.hc-sc.gc.ca/fn-an/food-guide-aliment/index_e.html
 

Canada's Food Guide provides resources to help guide food selection and promote the nutritional health of Canadians. Resources include outlines of the food groups, the recommended range of daily servings, background information about the food guide, and other information about healthy eating.


Dietitians of Canada
480 University Avenue
Suite 604
Toronto, ON  M5G 1V2
Phone: (416) 596-0857
Fax: (416) 596-0603
Email: centralinfo@dietitians.ca
Web Address: www.dietitians.ca
 

The Dietitians of Canada website provides a wide range of food and nutrition information, including fact sheets on frequently asked food and diet questions, quizzes and other tools to assess your diet habits, and meal planning guides.


Health Canada Food and Nutrition
Health Canada
Web Address: www.hc-sc.gc.ca/fn-an/index_e.html
 

The mission of the Food and Nutrition program is to protect and improve the health of the people of Canada through science-based policies and programs related to safe and nutritious food.


National Anemia Action Council
555 East Wells Street
Suite 1100
Milwaukee, WI 53202
Phone: (414) 225-0138
Web Address: www.anemia.org
 

The National Anemia Action Council (NAAC) helps raise awareness of the public and health professionals about the prevalence, symptoms, and treatment options of anemia. This nonprofit organization provides information to help improve the lives of people with anemia. Through education, the NACC helps improve detection, evaluation, treatment, and patient health.


Office of Dietary Supplements, National Institutes of Health
6100 Executive Blvd., Room 3B01, MSC 7517
Bethesda, MD  20892-7517
Phone: (301) 435-2920
Fax: (301) 480-1845
Email: ods@nih.gov
Web Address: http://dietary-supplements.info.nih.gov
 

The Office of Dietary Supplements (ODS) supports research and disseminates research results in the area of dietary supplements. The ODS also provides advice to other federal agencies regarding research results related to dietary supplements.


References

Other Works Consulted

  • Carmel R (2006). Cobalamin (Vitamin B12). In ME Shils et al., eds., Modern Nutrition in Health and Disease, 10th ed., pp. 482–497. Philadelphia: Lippincott Williams and Wilkins.
  • Gallagher ML (2008). The nutrients and their metabolism. In LK Mahan, S Escott-Stump, eds., Krause's Food and Nutrition Therapy, 12th ed., pp. 92–94. Philadelphia: Saunders Elsevier.
  • Green R (2010). Folate, cobalamin, and megaloblastic anemias. In K Kaushansky et al., eds., Williams Hematology, 8th ed., pp. 533–563. New York: McGraw-Hill.
  • Heimburger DC, et al. (2006). Clinical manifestations of nutrient deficiencies and toxicities: A resume. In ME Shils et al., eds., Modern Nutrition in Health and Disease, 10th ed., pp. 595–611. Philadelphia: Lippincott Williams and Wilkins.
  • Linker CA (2010). Vitamin B12 deficiency section of Blood disorders. In SJ McPhee, MA Papadakis, eds., Current Medical Diagnosis and Treatment, 49th ed., pp. 445–446. New York: McGraw-Hill.

Credits

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer Brian Leber, MDCM, FRCPC - Hematology
Last Revised February 16, 2011

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