Lactase

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Lactase

Lactase is an enzyme needed to convert milk sugar (lactose) into simple sugars that the body can use (glucose and galactose). Lactase is produced in the small intestine.

When a person becomes lactase-deficient (also called lactose-intolerant), he or she has difficulty digesting milk and milk products. The undigested lactose is used as food by bacteria that are normally found in the intestine. This can cause diarrhea, gas (flatulence), and cramps.

Production of lactase is highest at birth in full-term infants. It begins to decrease at about age 3. Lactose intolerance is common in adults. As their small intestines produce less lactase, most people naturally decrease the amount of lactose they eat or drink. Lactase production may also decline temporarily in response to damage of the intestinal lining, which can occur from a gastrointestinal illness.

Credits

Author	Jeannette Curtis
Author	Caroline Rea, RN, BS, MS
Editor	Kathleen M. Ariss, MS
Editor	Susan Van Houten, RN, BSN, MBA
Associate Editor	Tracy Landauer
Associate Editor	Pat Truman
Primary Medical Reviewer	Patrice Burgess, MD - Family Medicine
Primary Medical Reviewer	Adam Husney, MD - Family Medicine
Primary Medical Reviewer	Kathleen Romito, MD - Family Medicine
Last Updated	May 25, 2007

Last updated:	May 25, 2007
Author:	Caroline Rea, RN, BS, MS
Reviewed By:	Kathleen Romito, MD - Family Medicine
Editors:	Susan Van Houten, RN, BSN, MBA, Pat Truman

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