Vitamin B12 Deficiency: Symptoms & Signs

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Medically Reviewed on 3/15/2017

Vitamin B12 is a vitamin that is essential for many body functions, including the production of red blood cells. The body cannot make vitamin B12, and it needs to be supplied through the diet or by taking supplements. Vitamin B12 is found in foods of animal origin like meats, eggs, milk, and cheese. Vitamin B12 deficiency (cobalamin deficiency) is a condition that results when there is too little vitamin B12 in the body. Pernicious anemia is a kind of anemia that happens when the body is not able to absorb vitamin B12 through the digestive tract. A mild deficiency of vitamin B12 may not produce symptoms. Symptoms and signs, when they occur, can be similar to those of anemia, including

Other symptoms and signs include

  • digestive changes,
  • a smooth tongue, and
  • mental problems.

Causes of vitamin B12 deficiency

Consuming a strictly vegan diet without taking vitamin B12 supplements can cause vitamin B12 deficiency. Other causes include


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.

Medically Reviewed by a Doctor on 3/15/2017

Subscribe to MedicineNet's General Health Newsletter

By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.