Lactose Intolerance:
A Guide for Teens

You probably know someone with lactose intolerance. Maybe that person is a family member, a friend, or you. Lactose intolerance is very common; in fact, as many as 70% of the world's population is lactose intolerant. It is most common among Asian Americans, African Americans, and Native Americans, but affects people of all races and ethnic backgrounds. Read on to learn more facts about lactose intolerance!

What is lactose?

Lactose is a natural sugar found in milk and other dairy products. Your body makes an enzyme called lactase that breaks down lactose into sugars that your body can digest and use for energy.

What is lactose intolerance?

If you have lactose intolerance, your body may not be able to break down all the lactose that you eat or drink. People who are lactose intolerant have problems such as nausea, stomach cramps, gas, bloating, and diarrhea after they eat or drink milk or foods that contain milk.

How can I tell if I have lactose intolerance?

If you have nausea, stomach cramps, gas, bloating, or diarrhea within 15 minutes to several hours after eating or drinking foods with lactose, you may have lactose intolerance.

What should I do if I think I have lactose intolerance?

If you think you might be lactose intolerant, it is important for you to see your health care provider. Do not try to diagnose yourself. The same discomfort caused by lactose intolerance can be caused by other conditions including Crohn's disease, irritable bowel syndrome, and an infection of the small intestine. These conditions can be serious if they are not properly treated. Your health care provider is the only person who can confirm that you are lactose intolerant or if you have another condition. Once you have the right diagnosis you can work with your health care provider or a nutritionist to manage your symptoms.

How can your health care provider tell if you are lactose intolerant?

At first a health care provider may tell you to stop eating or drinking foods with lactose to see if your symptoms disappear. If your symptoms go away, it is likely that your health care provider will tell you that you are lactose intolerant. You may be scheduled to have a hydrogen breath test to confirm this diagnosis. A hydrogen breath test is done by breathing into a machine that measures the amount of hydrogen in your breath 60 minutes after you take lactose. If you are lactose intolerant, your body will produce more hydrogen than if you are lactose tolerant.

Can some people be more lactose intolerant than others?

Yes. There are different degrees of lactose intolerance. For example, some people may be able to drink 1/2 cup of milk without symptoms but have trouble with one 1 cup, while other people may have difficulty drinking a small amount of milk. Over time you will learn how much milk or other dairy products you can handle without having symptoms.

Are there different "types" of lactose intolerance?

Yes. Some people are born without the ability to make lactase. This is called primary lactose intolerance. People with this type of lactose intolerance have the most difficulty drinking or eating foods that contain lactose. Many people become lactose intolerant as they grow older.

Some people become lactose intolerant after having surgery or a gastrointestinal infection. Lactose intolerance can also be caused by malnutrition or taking certain medications. Secondary lactose intolerance is another name for this type of lactose intolerance. Secondary lactose intolerance usually goes away after 2 to 4 weeks.

Will I always be lactose intolerant?

If you became lactose intolerant because of an illness or medication, most likely you will not be lactose intolerant forever. If you were born with lactose intolerance or you are having more trouble digesting milk products than you did when you were younger, you might always have some degree of lactose intolerance.

What should I do if I'm lactose intolerant?

If your health care provider has told you that you are lactose intolerant, there are several things you can do so you won't feel gassy, bloated, have stomach cramps or diarrhea after you eat lactose-containing foods. Try these helpful tips:

• Know what foods and drinks contain lactose. Lactose is in most dairy products, some baked and processed foods such as bread, dry cereal, candy, cookies, salad dressings, cream soups, drink mixes, and prepared foods like pizza and lasagna.
• Pay attention to food labels. Food labels list all of the ingredients in order of the amount. The ingredients included in the largest amounts are listed first while those at the end of the list are in the smallest amounts. For example, if milk is listed first, you know that the product contains mostly milk. If you are lactose intolerant it's probably a product that you want to avoid or eat in small amounts.
• Start with small portions of dairy foods. If you can tolerate small portions, you might be able to add more a little at a time. As you slowly add dairy foods over time, you will be able to figure out just how much lactose your body can handle.
• Enjoy dairy foods with nondairy foods. Combining dairy foods with other foods slows the release of lactose into your body. This makes it easier for your body to digest and breakdown the lactose.
• Eat smaller portions of milk or dairy products more frequently. Instead of drinking full servings (1 cup or 8 ounces) of milk, try drinking smaller servings (1/2 cup or 4 ounces) throughout the day.
• Eat dairy foods that are naturally lower in lactose. Cheese and yogurt generally have less lactose than milk. This is because the lactose is partially broken down during the aging process.

What if these suggestions don't work?

If you still have discomfort after trying out these ideas, you may try a lactase supplement, such as Lactaid® or a generic brand, before having dairy rich foods. You can buy the lactase supplement as a chewable pill or liquid drops for a milk product. The supplement can be purchased without a prescription and will help your body to break down the lactose in the foods you eat or drink. You can also enjoy milk or ice cream that is lactose free such as Lactaid® milk and Lactaid® ice cream.

What else do I need to know?

• Learn about secret ingredients that contain lactose. These ingredients include dry milk solids (including non-fat milk solids), buttermilk, lactose, malted milk, sour or sweet cream, margarine, whey, whey protein concentrate, and cheese. Remember that baked and processed foods like cakes and cookies may also contain lactose. Check your food labels!
• Some medications contain lactose. Ask your doctor if there is lactose in any medications that you might be taking and read the label yourself, too.

Written by the Center for Young Women's Health Staff

Updated 5/1/2005

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