What causes vitamin B12 deficiency?

Vitamin B12 deficiency is most often caused by an inability of the body to properly digest and absorb vitamin B12. The inability to absorb vitamin B12 can be caused by diseases and conditions including:

  • Atrophic gastritis (a condition in which the stomach lining is inflamed and becomes thin)

  • Celiac disease (sensitivity to gluten from wheat and other grains, causing intestinal damage)

  • Crohn’s disease (an inflammatory bowel disease that can affect any part of the intestine)

  • Pernicious anemia (a result of atrophic gastritis with poor B12 absorption)

  • Surgical removal of a portion of the stomach or small intestine, such as with bariatric surgery   

In addition, some medications that treat diabetes, acid reflux, and peptic ulcers, for example, can affect how well your body can absorb vitamin B12.

Less commonly, vitamin B12 deficiency can occur as a result of not eating enough foods that contain vitamin B12. Foods that contain vitamin B12 include lean red meats, poultry, fish, brewer’s yeast, and dairy products, such as milk, cheese, and yogurt.

What are the risk factors for vitamin B12 deficiency?

A number of factors are thought to increase your chances of developing vitamin B12 deficiency:

  • Atrophic gastritis

  • Being an older adult

  • Celiac disease

  • Crohn’s disease

  • Following a strict vegan or vegetarian diet

  • Intestinal bacterial or tapeworm infestation

  • Pernicious anemia

  • Surgical removal of a portion of the small intestine   

People at risk include:

  • Vegans and strict vegetarians who do not eat meat, fish, eggs, or dairy products

  • Pregnant or breast-feeding women who are vegans or strict vegetarians

  • Breast-feeding infants of a vegetarian or vegan mother

How can you reduce your risk for vitamin B12 deficiency?

Most cases of vitamin B12 deficiency that are due to the body’s inability to properly absorb the vitamin through the digestive tract can be prevented only by successful treatment of the underlying cause. However, you may be able to lower your risk of vitamin B12 deficiency by:

  • Eating a diet that includes a sufficient amount of vitamin B12, which is found in lean red meats, poultry, fish, and dairy products, such as milk, cheese, and yogurt. Various food products such as breakfast cereals are also fortified with vitamin B12.

  • Taking vitamin B12 supplements as recommended if you are at high risk for developing vitamin B12 deficiency, such as if you follow a vegan diet or have celiac disease or Crohn’s disease

Keep in mind that some medicines that treat diabetes, acid reflux, and peptic ulcer disease can affect how well your body absorbs vitamin B12. Most important, talk with your health care provider about any supplements, prescription medications, and over-the-counter medications you take. They can tell you if any supplements you take could interfere or interact with your prescription medications.


What is vitamin B12 deficiency?

Vitamin B12 deficiency is a condition in which the body has inadequate stores of vitamin B12. This vitamin is essential for many aspects of health, including the production of red blood cells. Healthy numbers of red blood cells are critical for delivering oxygen and nutrients to the body’s cells and tissues.... Read more about vitamin b12 deficiencyintroduction


What are the symptoms of vitamin B12 deficiency?

The symptoms vary depending on the individual, the underlying cause, the severity of B12 deficiency, and other factors. In some cases, the symptoms of vitamin B12 deficiency can be vague, take years to develop, or may not be noticeable immediately.... Read more about vitamin b12 deficiencysymptoms


How is vitamin B12 deficiency treated?

Vitamin B12 deficiency is treatable. With prompt diagnosis and treatment, you can expect to have a good prognosis and a minimal risk of developing serious complications, such as nerve damage, anemia, or dementia.... Read more about vitamin b12 deficiencytreatments

Medical Reviewer: Williams, Robert, MD Last Annual Review Date: Dec 20, 2010 Copyright: © Copyright 2011 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

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