What is lactose intolerance?

Lactose intolerance is a condition caused by a lack of the enzyme lactase. Inadequate amounts of this enzyme can cause the body to be unable to digest lactose, which is a sugar found in milk. A lack of lactase can cause uncomfortable symptoms for some people and these people are said to be lactose intolerant.

The disorder affects some populations more than others:

• African-American, Jewish, Mexican-American, Native American, and Asian-American adults are commonly lactose intolerant.

What causes lactose intolerance?

Lactase is normally produced by the cells lining the small intestine where it breaks down lactose to be digested. Digestive diseases or injuries to the small intestine can reduce the amount of lactase produced. This can happen in childhood, however it is much more common that lactose intolerance develops over a period of many years and, therefore, more often affects adolescents and adults.

What are the symptoms of lactose intolerance?

Common symptoms, which begin about 30 minutes to two hours after consuming foods or beverages containing lactose, may include:

• Nausea
• Cramps
• Bloating
• Abdominal pain
• Gas
• Diarrhea
• Although uncommon, constipation can also be a symptom

The severity of symptoms varies depending on the amount of lactose consumed and the amount each individual can tolerate. The symptoms of lactose intolerance may resemble other conditions or medical problems so always consult your child's primary care provider for a diagnosis.

How is lactose intolerance diagnosed?

Lactose intolerance is usually diagnosed with a history and a physical. Your child’s primary care provider many order tests to confirm the diagnosis:

• Lactose tolerance test. This test measures the absorption of lactose in the digestive system. After fasting, the patient drinks a liquid that contains lactose. The diarrheal stools are then tested for lactose for the next 24 hours.
• Hydrogen breath test. The patient drinks a lactose-heavy beverage. The breath is then analyzed at regular intervals to measure the amount of hydrogen. When high levels of hydrogen are present in the breath, improper digestion of lactose is diagnosed.
• Stool acidity test. This test, used in infants and young children, measures the amount of acid in the stool. Lactic acid and glucose, produced by undigested lactose, and other fatty acids can be detected in a stool sample.

What is the treatment for lactose intolerance?

Treatment for lactose intolerance will be determined by your child's primary care provider based on:

• Your child's age, overall health, and medical history
• The extent of the disease
• Your child's tolerance for specific medications, procedures, or therapies
• The expectations for the course of the disease
• Your opinion or preference

Although, there is no treatment to improve the body's ability to produce lactase, symptoms caused by lactose intolerance can typically be controlled by limiting lactose in the diet. In addition, lactase enzymes (available over the counter) may be suggested to help the symptoms.

The American Academy of Pediatrics released guidelines for treating lactose intolerance in 2006. These guidelines support the use of dairy foods as an important source of calcium for bone growth and maintenance. Therefore, instead of eliminating dairy from the diet, dairy foods should be tried to see which ones can be tolerated. While the symptoms of lactose intolerance can be unpleasant, the condition does not damage the body.

How can children with lactose intolerance get enough calcium?

Calcium is essential for the growth and repair of bones throughout. Because milk and other dairy products are a major source of calcium, parents must consider how best to ensure adequate amounts of calcium in a diet that includes little or no milk.

The dietary recommended intake (RDI) values for calcium vary by age group:

• 0 to 6 months – 200 mg
• 6 months to 1 year – 260 mg
• 1 to 3 years – 700 mg
• 4 to 8 years – 1,000 mg
• 9 to 18 years – 1,300 mg

Non-dairy foods that are high in calcium include:

• Green vegetables, such as collard greens, turnip greens, broccoli, and kale
• Fish with soft, edible bones, such as salmon and sardines
• Yogurt with active cultures (evidence shows that the cultures used in making yogurt produce some of the lactase enzyme and are therefore well-tolerated by people with lactose intolerance)

Your child's primary care provider may prescribe a calcium supplement if your child is unable to get enough calcium from his or her diet. Vitamin D is necessary for the body to absorb calcium; therefore, your child's provider may also prescribe a vitamin D supplement.