What I need to know about 

Lactose Intoler Lactose Intolerance 

NATIONAL INSTITUTES OF HEALTH 

U.S. Department 

of Health and 

Human Services National Digestive Diseases 

Information Clearinghouse 

 

 

What I need to know about 

Lactose Intolerance 

 

U.S. Department 

of Health and 

Human Services 

NATIONAL INSTITUTES OF HEALTH 

National Digestive Diseases 

Information Clearinghouse

Contents 

What is lactose intolerance? .................................. 1 

Who gets lactose intolerance? ............................... 2 

What are the symptoms of 

lactose intolerance? ................................................ 3 

How is lactose intolerance diagnosed? ................. 4
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What should I do if I think my child is 

lactose intolerant?................................................... 5
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How is lactose intolerance managed? ................... 5
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How will I know if a food has lactose?.................. 7
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How will I get the calcium I need? ...................... 11
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Points to Remember ............................................. 13
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Hope through Research ....................................... 14
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Pronunciation Guide............................................. 14
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For More Information .......................................... 15
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Acknowledgments ................................................. 15
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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 page 14 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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intolerance? 

What are the symptoms of lactose 

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. 

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 

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●	 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 

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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 

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●	 liquid and powdered milk-based meal 

replacements 

●	 protein powders and bars 

●	 candies 

●	 nondairy liquid and powdered coffee creamers 

●	 nondairy whipped toppings 

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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 

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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. 

12 
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.

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 

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. 

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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 is available at www.digestive.niddk.nih.gov.

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. 
–

U.S. DEpArTmENT OF HEALTH 

AND HUmAN SErvICES 

National Institutes of Health

NIH Publication No. 10–2751 

June 2010