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.

Vitamin B12 is a water-soluble vitamin that must be ingested daily and absorbed effectively by the digestive tract in order to maintain optimal health. Most people get enough vitamin B12 by eating a variety of foods. Those that naturally contain vitamin B12 include lean red meats, poultry, fish, brewer’s yeast, and dairy products, such as milk, cheese, and yogurt. Vitamin B12 is also added to some breakfast cereals, breads, and other fortified food products.

Vitamin B12 deficiency is most common in people who have a disease or condition in which the body is unable to absorb vitamin B12 from ingested foods. It is also relatively common in older adults. One in 31 adults age 51 years and older has a vitamin B12 deficiency, according to the Centers for Disease Control and Prevention (Source: CDC).

Less commonly, vitamin B12 deficiency results from an inadequate intake of foods that contain vitamin B12.

Untreated vitamin B12 deficiency can lead to serious complications, such as anemia, nerve damage, and growth abnormalities. Seeking regular medical care and following your treatment plan can help reduce the risk of serious complications from vitamin B12 deficiency.


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.

Some symptoms of vitamin B12 deficiency are due to a decreased production of red blood cells, which are necessary to carry vital oxyge... Read more about vitamin b12 deficiencysymptoms


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)

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.

Treatment of vitamin B12 deficiency involves replacing the body’s depleted stores of vitamin B12. This generally includes:

Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: Sep 30, 2013 Copyright: © Copyright 2014 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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