Center for Digestive Diseases

UNM Hospitals Center
for Digestive Diseases

1001 Martin Luther King Ave. NE
Albuquerque, New Mexico 87106

(505)272-2530 or

UNMH: (505)272-6839
CDD: (505)925-7849

Lactose Intolerance

What is lactose intolerance?

Lactose is a sugar that is present in milk and therefore commonly found in ice cream, cheese and other milk-containing products.  In order to be absorbed, lactose must first be broken down by an enzyme called lactase in the lining of the small intestine.  Lactose intolerance is a condition in which there are insufficient levels of lactase in the small intestine.  As a result, lactose is not absorbed and continues through the intestine where bacteria break it down into gases and other compounds that cause symptoms of bloating, abdominal pain and more.

What are the symptoms of lactose intolerance?

Deficiency of lactase results in a lack of absorption of lactose.  As a result lactose is broken down in the small intestine by bacteria into gases that cause bloating and flatulence and other compounds that are irritating to the colon and cause diarrhea. 

How is lactose intolerance diagnosed?

Obtaining a thorough clinical history about symptoms and diet is often very helpful in making the diagnosis.  A trial eliminating lactose from your diet is often recommended in order to assess if your symptoms are related to lactose intake.  A lactose breath test is a simple non-invasive test that can be used to make the diagnosis of lactose intolerance.  In this test a dose of lactose is eaten and then the amount of hydrogen and methane in expired breath is measured. Because lactose that is not absorbed it is broken down by bacteria into hydrogen and methane, measurement of these gases allows for the diagnosis of lactose intolerance to be made.  Your doctor may order stool tests, blood tests, colonoscopy or upper endoscopy during your evaluation. 

What is the treatment for lactose intolerance?

The mainstay of treatment is to avoid dairy products (milk, cheese, ice cream and other milk-containing products).  Usually small amounts of dairy products are tolerated without symptoms.  Yogurt is usually well-tolerated due to its low level of lactase. Some cheeses can also be tolerated for the same reason.  Lactose-free milk contains lactase enzyme and can be consumed without symptoms.  These are available at most grocery stores.   Soy milk, rice milk and almond milk are alternatives to cow’s milk.  Lactase enzyme drops or tablets taken with milk or other dairy products can decrease symptoms.