When Your Child Has Lactose Intolerance

Two boys eating frozen treats.

Lactose intolerance is not a milk allergy. Having lactose intolerance means that your child can’t digest lactose. This is a sugar found in milk and other dairy products. To digest lactose, the body needs an enzyme (a kind of protein) called lactase. Lactase is made by cells in the small intestine. Your child’s body may not make enough lactase to digest lactose. Undigested lactose can cause uncomfortable symptoms. Lactose intolerance can be managed so your child can feel better.

What are the symptoms of lactose intolerance?

Lactose intolerant children can have painful symptoms after eating or drinking dairy products. Common symptoms include:

  • Bloating

  • Excessive gas

  • Nausea

  • Vomiting

  • Diarrhea

  • Pain or cramping in the belly

  • Symptoms happen 30 minutes to 2 hours after consuming milk or milk products. Symptoms range from mild to severe based on the amount of lactose your child ate or drank and the amount your child can tolerate. 

How is lactose intolerance diagnosed?

The most common test used to diagnose lactose intolerance is called the hydrogen breath test. This test measures the level of a gas called hydrogen in your child’s breath. Hydrogen is produced by bacteria in the large intestine (colon) in response to undigested lactose. Hydrogen is carried through the bloodstream to the lungs, where it is breathed out. High levels of hydrogen in your child’s breath means that lactose is not being digested properly. Other tests include stool tests. These measure the amount of undigested sugar in the stool as a marker of undigested lactose. Sometimes your child's healthcare provider will recommend an endoscopy. During this procedure, samples may be taken of the small intestine. The absence of lactase shows a lactose intolerance. 

How is lactose intolerance treated?

One way to manage your child’s symptoms is to reduce or eliminate sources of lactose. This includes most dairy products, such as:

  • Milk

  • Butter

  • Cream

  • Cheese

  • Ice cream

Children with lactose intolerance can sometimes eat or drink dairy products without symptoms. At first your child’s healthcare provider may want to remove all lactose from your child’s diet to stop symptoms. Then you can work with the healthcare provider to learn what kinds of dairy products your child can tolerate. Your child's healthcare provider may recommend a lactase enzyme supplement to help your child digest lactose without having symptoms.

Kids need calcium and vitamin D

Dairy products are a good source of calcium and vitamin D. Kids need calcium and vitamin D for bone growth and strength. Talk with your child’s healthcare provider about ways to give your child enough calcium and vitamin D. Foods that contain calcium include:

  • Green vegetables such as broccoli, kale, bok choy (Chinese cabbage), and turnip greens

  • Fish with edible bones, such as canned salmon

  • Alfalfa or soy sprouts

  • Tofu, soybeans, pinto beans, and navy beans

  • Almonds

  • Sesame seeds

  • Molasses

  • Calcium-fortified drinks, such as orange juice, soy milk, and rice milk

  • Lactose-free milk and other lactose-free dairy products