What is lactose intolerance?
Lactose intolerance is a condition caused by a lack of an enzyme called lactase, which, in turn, causes the body to be unable to digest lactose, a sugar found in milk and milk products.
Lactase is normally produced by cells lining the small intestine where it breaks lactose down into a form that can be absorbed by the blood. A lack of lactase can cause uncomfortable symptoms for some people. Those who do exhibit the symptoms are said to be lactose intolerant.
Thirty to 50 million Americans (adults and children) are lactose intolerant. The disorder affects some populations more than others:
- Seventy-five percent of all African-American, Jewish, Mexican-American, and Native American adults are lactose intolerant.
- Ninety percent of Asian-American adults are lactose intolerant.
- Lactose intolerance is least common among people with a northern European heritage.
What causes lactose intolerance?
Digestive diseases or injuries to the small intestine can reduce the amount of enzymes produced, and is the usual cause of lactose intolerance in young children. However, most cases of lactose intolerance develop over a period of many years in adults.
Treatment for lactose intolerance:
Specific treatment for lactose intolerance will be determined by your physician based on:
- your age, overall health, and medical history
- extent of the condition
- your tolerance for specific medications, procedures, or therapies
- expectations for the course of the condition
- your opinion or preference
Although there is not a treatment to improve the body’s ability to produce lactase, symptoms caused by lactose intolerance can be controlled with a proper diet. In addition, lactase enzymes may be suggested by your physician.
Young children with lactase deficiency should be under the care of a physician.
In September of 2006, the American Academy of Pediatrics released new guidelines for treating lactose intolerance. These guidelines support the use of dairy foods as an important source of calcium for bone growth and maintenance, as well as of other nutrients needed for growth in children and adolescents.
In the past, it had been recommended that dairy products should be eliminated from the diet to treat lactose intolerance. The new guidelines suggest that dairy foods should be tried to see which ones can be tolerated better than others. While the symptoms of lactose intolerance can be unpleasant, the condition does not damage the body. Thus, dairy foods that cause less disagreeable symptoms should be used in the diet to ensure adequate intake of calcium and other important nutrients.
Calcium for People with Lactose Intolerance
Calcium is essential for the growth and repair of bones throughout life, and has been suggested as a preventive for other diseases. Because milk and other dairy products are a major source of calcium, lactose intolerant children and adults must be concerned with getting enough calcium in a diet that includes little or no milk.
The recommended daily dietary allowance (RDA) for calcium, released in 2004 by the National Academy of Sciences, varies by age group:
- 0 to 6 months, 210 mg
- 6 months to 1 year, 270 mg
- 1 to 3 years, 500 mg
- 4 to 8 years, 800 mg
- 9 to 18 years, 1,300 mg
- 19 to 50 years, 1,000 mg
- 51 to 70 years, 1,200 mg
- pregnant and nursing women under age 19, 1,300 mg
- pregnant and nursing women over age 19, 1,000 mg
Many nondairy foods are high in calcium, including the following:
- green vegetables, such as collard greens, turnip greens, broccoli, and kale (Swiss chard, spinach, and rhubarb are not listed because the body cannot use their calcium content – they contain substances called oxalates, which block calcium absorption)
- fish with soft, edible bones, such as salmon and sardines
- yogurt with active cultures (may be a good source of calcium for many people with lactose intolerance, as evidence shows that the bacterial cultures used in making yogurt produce some of the lactase enzyme required for proper digestion)
Vitamin D is necessary for the body to absorb calcium; therefore, a diet should provide an adequate supply of vitamin D. Sources of vitamin D include eggs and liver, as well as sunlight.