An Introduction to Lactose Intolerance
Lactose intolerance is the inability to digest significant amounts of lactose (the major sugar found in milk).
People sometimes confuse lactose intolerance with cow's milk intolerance because the symptoms are often the same. However, the two conditions are not related. Being intolerant to cow's milk is an allergic reaction triggered by the immune system. Lactose intolerance is a problem caused by the
digestive system.
What Is Lactose Intolerance?
Lactose intolerance is a condition that results from a deficit of lactase (lactase deficiency), an enzyme produced by the cells lining the small intestine. Lactase is necessary to digest lactose, the natural sugar found in milk. Lactase breaks down lactose (milk sugar) into two simpler forms of sugar called glucose and galactose, which are then absorbed into the bloodstream. When there is a shortage of lactase, the body is not able to break down lactose, and it travels through the intestines unchanged. In the intestines, undigested lactose has a laxative effect and stimulates the growth of bacteria that produce significant amounts of gas. Within 30 minutes to 2 hours after ingesting lactose, abdominal cramping and
diarrhea often occur. These symptoms are essential to a diagnosis of lactose intolerance.
Not all people with lactase deficiency have the symptoms commonly associated with lactose intolerance, but those who do are said to have lactose intolerance.
Between 30 and 50 million Americans are lactose intolerant, and certain ethnic and racial populations are more affected than others. Up to 80 percent of African Americans, 80 to 100 percent of American Indians, and 90 to 100 percent of Asian Americans are lactose intolerant. The condition is least common among people of northern European descent.
Causes of Lactose Intolerance
The cause of lactose intolerance is a shortage of the enzyme lactase (lactase deficiency).
Some causes of a lactase deficiency are well known; in other cases, research scientists are not sure why a person develops this deficiency.
There are two general categories of lactase deficiency:
- Primary lactase deficiency
- Secondary lactase deficiency.
The severity of lactose intolerance symptoms depends on many factors, including the amount of lactose a person can tolerate and a person's age, ethnicity, and digestion rate.
Common symptoms of lactose intolerance, which range from mild to severe, include:
- Nausea
- Cramps
- Abdominal pain
- Bloating
- Gas
- Diarrhea
- Odd-smelling stool
- Floating stool.
Lactose intolerance can be hard to diagnose based on symptoms alone. People sometimes think they suffer from lactose intolerance because they have the symptoms associated with lactose intolerance. However, they may not know that other conditions, such as irritable bowel syndrome or a milk allergy in children, can cause similar symptoms.
In order to make a diagnosis, a doctor will ask a number of questions about a person's symptoms, perform a physical exam, and recommend certain tests. While a doctor can use lactose intolerance tests to make the diagnosis, he or she may first recommend eliminating cow's milk from the diet to see if the symptoms go away.
- Lactose tolerance test
- Hydrogen breath test
- Stool acidity test.
Treating Lactose Intolerance
Lactose intolerance is generally fairly easy to treat. For most people,
lactose intolerance treatment involves modifying their diet. While no treatment can improve the body's ability to produce lactase, a carefully chosen diet, with
calcium supplements (if the doctor or dietitian recommends them), is the key to reducing symptoms.
