Symptoms and Signs of Lactose Intolerance

Medical Author:
Medically Reviewed on 8/8/2022

Doctor's Notes on Lactose Intolerance

Lactose intolerance is a common disorder caused by the inability to digest lactose, a carbohydrate found in milk and other dairy products. Normally, lactose is broken up by an enzyme called lactase located on the lining of the intestines that works to break up lactose into its smaller carbohydrate components, glucose and galactose. These two smaller molecules are more easily absorbed by the body and used for metabolism. Most commonly, lactose intolerance is an acquired condition. The intestinal wall can become damaged, commonly from infections or certain medications such as gastroenteritisceliac disease, Crohn's disease, radiation therapy, diabetic enteropathy, HIV enteropathy, and some chemotherapeutic drugs. The complete absence of lactase at birth is a rare genetic condition where the gene responsible for producing the lactase enzyme is defective.

Symptoms of lactose intolerance include 

What is the treatment for lactose intolerance?

Lactose intolerance has no cure; however, most people can control symptoms with diet changes that reduce lactose-containing foods like milk and other dairy products. In addition, some patients can take lactase tablets that break down lactose and thus reduce the chance of symptom developments. Also, individuals may use lactase drops added to foods and/or drinks before ingestion.

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