Vitamin B12

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Vitamin B12 benefits

Vitamin B12 source

Cobalamin; Cyanocobalamin

A lack of vitamin B12 (B12 deficiency) occurs when the body does not get or is unable to absorb the amount of vitamin that the body needs.

• Many people over age 50 lose the ability to absorb vitamin B12 from foods.
• People who follow a strict vegetarian or vegan diet and do not consume eggs or dairy products may need vitamin B12 supplements.
• Those who have had gastrointestinal surgery, such as weight loss surgery, lose the ability to absorb vitamin B12.
• People who have digestive disorders, such as celiac disease or Crohn's disease, may not absorb enough vitamin B12.

Low levels of B12 can cause:

• Anemia
• Loss of balance
• Numbness or tingling in the arms and legs
• Weakness

See also:

• Megaloblastic anemia
• Pernicious anemia

Review Date: 02/15/2011
Reviewed By: Alison Evert, MS, RD, CDE, Nutritionist, University of Washington Medical Center Diabetes Care Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org).

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