What I need to know about Lactose Intolerance
On this page:
- What is lactose intolerance?
- Who gets lactose intolerance?
- What are the symptoms of lactose intolerance?
- How is lactose intolerance diagnosed?
- What should I do if I think my child is lactose intolerant?
- How is lactose intolerance managed?
- How will I know if a food has lactose?
- How will I get the calcium I need?
- Points to Remember
- Hope through Research
- Pronunciation Guide
- For More Information
- Acknowledgments
What is lactose intolerance?
Lactose intolerance* means you have trouble digesting lactose. Lactose is the sugar found in milk and foods made with milk. The small intestine needs lactase enzyme to break down lactose. With lactose intolerance, you may not feel well when you eat or drink something with lactose because you don’t have enough lactase enzyme.
*See Pronounciation Guide for tips on how to say the words in bold type.
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Who gets lactose intolerance?
Many people have problems digesting lactose. Some people become lactose intolerant as children. In others, the problem starts when they are teenagers or adults. Lactose intolerance is rare in babies. Premature babies may be lactose intolerant for a short time after they are born.
Lactose intolerance is common in certain areas of the world. Certain groups are more likely to be lactose intolerant:
- Asian Americans
- African Americans
- American Indians
- Hispanics/Latinos
- people with southern European heritage
People of northern European descent are least likely to be lactose intolerant.
If your small intestine has been damaged, it may produce less lactase enzyme, causing you to become lactose intolerant. The small intestine can be hurt by
- diseases such as celiac disease or Crohn’s disease
- infections
- surgery
- injuries
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What are the symptoms of lactose intolerance?
If you have lactose intolerance, you may not feel well after you eat or drink milk and milk products.
You may also have
- cramps or pain in your abdomen, the area between your chest and hips
- bloating or swelling in your abdomen
- gas
- diarrhea
- nausea
Some illnesses can cause these same symptoms. If you have these symptoms after you eat or drink milk and milk products, see your doctor.
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How is lactose intolerance diagnosed?
To find out if you have lactose intolerance, your doctor will ask about your symptoms. The doctor may ask you to stop eating or drinking milk and milk products to see if your symptoms improve.
Your doctor might perform other tests to confirm your diagnosis:
- Breath tests. You will drink a sweet drink with lactose in it. Then your breath is tested to see if you were able to digest the lactose.
- Stool test. Your stool can be tested to see if you digest lactose. Stool is the waste that passes through the rectum as bowel movements. The stool test is often used to check babies for lactose intolerance.
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What should I do if I think my child is lactose intolerant?
Talk with your doctor before making any changes in your child’s diet. While lactose intolerance is more common in adults, children may be lactose intolerant.
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How is lactose intolerance managed?
You can change your diet to manage your symptoms. Most people with lactose intolerance do not have to give up milk or milk products. You may be able to tolerate milk and milk products if you
- drink small amounts of milk—4 ounces or less—at a time
- drink small amounts of milk with meals
- gradually add small amounts of milk and milk products to your diet and see how you feel
- eat milk products that are easier for people with lactose intolerance to digest, such as yogurt and hard cheeses like cheddar and Swiss
You can also use over-the-counter products that may help you digest milk and milk products. You can
- take a tablet that contains the lactase enzyme when you eat foods that contain lactose
- add liquid lactase drops to liquid milk products
You can also find lactose-free and lactose-reduced milk and milk products at the grocery store. These products have the same nutrients and benefits as regular milk.
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How will I know if a food has lactose?
Lactose is found in milk and all foods made with milk, such as
- ice cream
- cream
- butter
- cheese
- cottage cheese
- yogurt
Rarely, people with lactose intolerance are bothered by small amounts of lactose. Some boxed, canned, frozen, packaged, and prepared foods contain small amounts of lactose. These foods include
- bread and other baked goods
- waffles, pancakes, biscuits, cookies, and mixes to make them
- prepared or frozen breakfast foods such as doughnuts, frozen waffles and pancakes, toaster pastries, and sweet rolls
- boxed breakfast cereals
- instant potatoes, soups, and breakfast drinks
- potato chips, corn chips, and other packaged snacks
- prepared meats, such as bacon, sausage, hot dogs, and lunch meats
- margarine
- salad dressings
- liquid and powdered milk-based meal replacements
- protein powders and bars
- candies
- nondairy liquid and powdered coffee creamers
- nondairy whipped toppings
Look for certain words on food labels. These words mean the food has lactose in it:
- milk
- lactose
- whey
- curds
- milk by-products
- dry milk solids
- nonfat dry milk powder
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How will I get the calcium I need?
Milk and milk products are the most common sources of calcium. Calcium is a mineral the body needs for strong bones and teeth. If you are lactose intolerant, make sure you get enough calcium each day.
Other foods contain calcium, such as
- canned salmon or sardines with bones
- broccoli and other leafy green vegetables
- oranges
- almonds, Brazil nuts, and dried beans
- soy milk and tofu
- products with added calcium, such as orange juice
To absorb calcium, your body needs vitamin D. Be sure to eat foods that contain vitamin D, such as eggs, liver, and certain kinds of fish like salmon and tuna. Also, getting enough sun helps your body make vitamin D.
Vitamin D is added to some milk and milk products. If you’re able to drink small amounts of milk or eat yogurt, choose varieties that have vitamin D added.
It’s hard to get enough calcium and vitamin D even if you eat and drink milk and milk products. Talk with your doctor about how to get calcium and vitamin D in your diet. Ask if you should also take a supplement to get enough calcium, vitamin D, or other nutrients.
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Points to Remember
- Lactose intolerance means you have trouble digesting lactose.
- If you have lactose intolerance, you may not feel well after you eat or drink milk and milk products.
- Many people with lactose intolerance can tolerate small amounts of milk—4 ounces or less—at a time, especially with meals.
- You may be able to gradually add small amounts of milk and milk products to your diet.
- You can use over-the-counter products that may help you digest milk and milk products.
- If you are lactose intolerant, make sure you get enough calcium each day. Talk with your doctor about how to get enough calcium in your diet. Ask if you should take a calcium supplement.
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Hope through Research
Researchers have found the genes that cause lactose intolerance. They are working to develop a genetic test for this condition. This test would be simpler and more accurate than current tests. It would help doctors tell the difference between lactose intolerance and conditions with similar symptoms, such as irritable bowel syndrome.
Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research. For information about current studies, visit www.ClinicalTrials.gov.
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Pronunciation Guide
abdomen (AB-doh-men)
calcium (KAL-see-uhm)
enzyme (EN-zym)
intestine (in-TESS-tin)
lactase (LAK-tayss)
lactose intolerance (LAK-tohss) (in-TOL-ur-uhnss)
supplement (SUH-pluh-muhnt)
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For More Information
American Dietetic Association
120 South Riverside Plaza, Suite 2000
Chicago, IL 60606–6995
Internet: www.eatright.org 
International Foundation for Functional Gastrointestinal Disorders
P.O. Box 170864
Milwaukee, WI 53217–8076
Phone: 1–888–964–2001 or 414–964–1799
Fax: 414–964–7176
Email: iffgd@iffgd.org
Internet: www.iffgd.org
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Acknowledgments
Publications produced by the Clearinghouse are carefully reviewed by both NIDDK scientists and outside experts. This publication was reviewed by Rachel Fisher, M.S., M.P.H., R.D., and Jean Pennington, Ph.D., R.D., Division of Nutrition Research Coordination, NIDDK.
This publication may contain information about medications. When prepared, this publication included the most current information available. For updates or for questions about any medications, contact the U.S. Food and Drug Administration toll-free at 1–888–INFO–FDA (1–888–463–6332) or visit www.fda.gov. Consult your doctor for more information.
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National Digestive Diseases Information Clearinghouse
2 Information Way
Bethesda, MD 20892–3570
Phone: 1–800–891–5389
TTY: 1–866–569–1162
Fax: 703–738–4929
Email: nddic@info.niddk.nih.gov
Internet: www.digestive.niddk.nih.gov
The National Digestive Diseases Information Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health of the U.S. Department of Health and Human Services. Established in 1980, the Clearinghouse provides information about digestive diseases to people with digestive disorders and to their families, health care professionals, and the public. The NDDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government agencies to coordinate resources about digestive diseases.
This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired.
This publication may contain information about medications. When prepared, this publication included the most current information available. For updates or for questions about any medications, contact the U.S. Food and Drug Administration toll-free at 1–888–INFO–FDA (1–888–463–6332) or visit www.fda.gov. Consult your health care provider for more information.
NIH Publication No. 10–2751
June 2010
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Page last updated May 10, 2012
