Intrinsic factor is a protein produced by cells in the stomach lining. It is needed for the intestines to absorb vitamin B12 efficiently.

In a disease called pernicious anemia, immune system damage to the stomach lining can cause a lack (deficiency) of intrinsic factor. Pernicious anemia causes vitamin B12 deficiency, which leads to a low red blood cell count (anemia).

Intrinsic factor deficiencies can also be caused by other reasons, such as:

• Inherited conditions
• Other diseases
• Surgical removal of the stomach

Next Section

Intrinsic factor Prevention

Review Date: 01/31/2010
Reviewed By: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. 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)