Information on the causes and symptoms of lactose intolerance.

What is Lactose Intolerance?

Lactose intolerance is caused by deficiency of the enzyme lactase, which is produced by cells in the small intestine. Lactase aids in the digestion of the milk sugar lactose, breaking it down into two simple sugars, glucose and galactose, that are then absorbed into the bloodstream. People with lactose intolerance are unable to digest lactose, leading to gastrointestinal distress. Lactose intolerance should not be confused with milk allergies which are more severe and are caused by an allergic reaction.

What Causes Lactose Intolerance?

As the body ages, it produces less of the enzyme lactase needed for the digestion of dairy products. As these levels decline, a deficiency causes digestive problems when dairy is consumed. Most people do not become lactose intolerant until late in adolescence or adulthood. Research has shown a genetic link to lactase deficiency. Lactase deficiency can also be caused by injury to the small intestine that can occur with severe diarrhea, Celiac disease and Crohn's disease. In very rare cases, infants may become lactose intolerant.

Symptoms of Lactose Intolerance

Symptoms of lactose intolerance can vary from mild to severe depending on the degree of lactase deficiency in the body. Symptoms include bloating, cramping, abdominal pain, gurgling in the lower abdomen, gas, loose stools or diarrhea and sometimes vomiting. Symptoms usually appear 30 minutes up to a couple of hours after drinking milk or consuming dairy products.

Diagnosing Lactose Intolerance

Your doctor will likely question you about your symptoms and your response to reducing dairy in your diet. A diagnosis can be confirmed with testing. A lactose tolerance test is most common. A liquid that contains a high amount of lactose is administered. After two hours, blood tests are used to determine the amount of glucose in your bloodstream. If the blood-glucose level doesn't rise, it indicates the body isn't properly digesting lactose. Hydrogen breath tests may also be performed. A reading of larger than normal amounts of exhaled hydrogen is an indicator that lactose is not being properly digested and absorbed.

Help for Lactose Intolerance

Lactose intolerance is generally treated through dietary modification. No treatments are available that improve the body's ability to produce lactase, but there are lactase supplements available to help ease digestion when dairy products can't be avoided. There are also several lactose free dairy products in production.