digestive disorders
Lactose Intolerance
Introduction
Lactose intolerance is the inability to digest the sugar lactose because of a lack of the digestive enzymelactase, leading to diarrhea and abdominal cramping. Lactose intolerance is caused by a lack of the enzymelactase. Symptoms in children include diarrhea and poor weight gain, whereas symptoms in adults include abdominal bloating and cramps, diarrhea, flatulence, and nausea. The diagnosis is based on recognizing that symptoms occur after a person has consumed dairy products and can be confirmed with a hydrogen breath test. Treatment involves taking supplementallactaseenzymes and avoiding lactose, particularly in dairy products. Lactose, the predominant sugar found in milk and other dairy products, is broken down by the enzymelactase, which is produced by the cells in the inner lining of the small intestine.Lactasebreaks down lactose, a complex sugar, into its two components, glucose and galactose. These simple sugars are then absorbed into the bloodstream through the intestinal wall. Iflactaseis lacking, lactose cannot be digested and absorbed. The resulting high concentration of lactose draws fluid into the small intestine, causing watery diarrhea. The lactose then passes into the large intestine, where it is fermented by bacteria, producing gases that cause flatulence, bloating, and abdominal cramps. is different from lactose intolerance. In contrast to lactose intolerance, people with cow's milk allergy can digest milk properly, but proteins in the cow's milk trigger a response by the immune system (see Overview of Allergic Reactions ). Cow's milk allergy usually affects children. Except for people of Northern European descent, most healthy adults cannot digest significant amounts of lactose and are thus normally "lactose intolerant." 