Intrinsic factor is a protein that helps your intestines absorb vitamin B12. It is made by cells in the stomach lining.
Intrinsic factor is an important protein that helps your body absorb vitamin B12. Vitamin B12 is needed for red blood cells to form and grow.
Some people do not make enough intrinsic factor or have a condition that destroys it. If your body does not make enough intrinsic factor, you can develop a type of vitamin B12 deficiency called pernicious anemia.
Surgical removal of the stomach and certain other health conditions can also cause you to stop making intrinsic factor.
Antony AC. Megaloblastic anemias. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 167.
Antony AC. Megaloblastic anemia. In: Hoffman R, Benz EJ, Shattil SS, et al., eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2008:chap 39.
Update Date 2/25/2014
Updated by: Diane M. Horowitz, MD, Rheumatologist and Continuing Medical Education Director, North Shore Long Island Jewish Health System, Great Neck, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.