Lactose Intolerance: 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.

Lactose intolerance is a condition in which the body is unable to fully digest lactose, a form of natural sugar found in milk. Lactose intolerance is not the same thing as a food allergy and is a relatively common condition. It is more common in Native Americans and people of Asian, African, and South American descent than among people of European ancestry. The condition results from a deficiency of lactase, an enzyme made in the small intestine that breaks down lactose. Symptoms occur when an affected person consumes milk or dairy products. Symptoms and signs can include

The degree or severity of symptoms can vary among affected people.

REFERENCE:

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 8/21/2017

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