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Lactose Intolerance


You probably know someone with lactose intolerance. Maybe that person is a family member, a friend, or you. It's most common among Asian Americans, African Americans, individuals of Jewish descent, Mexican-Americans, and Native Americans, but affects people of all races and ethnic backgrounds.


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 smaller 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 lactose.


How can I tell if I have lactose intolerance?

If you have nausea, stomach cramps, gas, bloating, or diarrhea within 30 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?

Do not try to diagnose yourself. If you think you might be lactose intolerant, it is important for you to see your health care provider. 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 medical condition. Once you have the right diagnosis, you can work with your health care provider or a nutritionist to manage your symptoms.


How can my health care provider tell if I'm lactose intolerant?

At first, your 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 also 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 within 90 minutes of consuming 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. Other people may have difficulty drinking even 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 the enzyme lactase. People with this type of lactose intolerance have the most difficulty drinking or eating foods that contain lactose. More commonly, people become lactose intolerant as they grow older and their body slowly makes less and less lactase. Some people become lactose intolerant after having surgery or a gastrointestinal infection.


Will I always be lactose intolerant?

If you became lactose intolerant because of an illness, 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, or have stomach cramps or diarrhea after you eat lactose-containing foods.


Try these helpful tips:

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 foods that contain lactose. 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?

If you're lactose intolerant, you probably won't need to completely cut out milk or other dairy foods from your diet. These foods provide calcium for your body and other important nutrients. Managing your lactose intolerance is possible and not as difficult as you might think.


If you're concerned about lactose intolerance, here's a tip on how to bring it up with your health care provider: I get really nauseous and gassy when I eat dairy. Could I be lactose intolerant?


Written by the CYWH and YMH Staff at Boston Children's Hospital


Updated: 11/13/2013


Related Guides:

Milk Allergy

Milk allergy is different from lactose intolerance. Milk allergy is an allergic reaction to milk proteins. Someone who has lactose intolerance isn't allergic to milk, they just can't digest the lactose sugar found in milk...



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