What Is Lactose Intolerance?
Lactose intolerance is a common problem. It happens when your body does not have enough lactase, which is an enzyme produced in the small intestine. Lactase is necessary to digest lactose – the natural sugar found in milk and other dairy products. In the intestines, undigested lactose leads to the buildup of gas. Within 30 minutes to 2 hours after eating dairy products containing lactose, people with lactose intolerance start to develop stomach cramps and diarrhea. These two symptoms must be present for a person to be diagnosed with lactose intolerance.
Between 30 and 50 million Americans are lactose intolerant. The disorder is more common in some ethnic groups than in others. For example, up to 75 percent of all adult African Americans and Native Americans and 90 percent of Asian Americans are considered to be lactose intolerant. In contrast, people of northern European descent are less likely to be lactose intolerant.
What Is Osteoporosis?
The Link Between Lactose Intolerance and Osteoporosis
Bone Health Strategies
Resources
What Is Osteoporosis?
Osteoporosis is a condition in which bones become less dense and more likely to fracture. Fractures from osteoporosis can result in pain and disability. Osteoporosis is a major health threat for an estimated 44 million Americans, 68 percent of whom are women.
Risk factors for developing osteoporosis include:
thinness or small frame
family history of the disease
being postmenopausal and particularly having had early menopause
abnormal absence of menstrual periods (amenorrhea)
prolonged use of certain medications, such as those used to treat lupus, asthma, thyroid deficiencies, and seizures
low calcium intake
lack of physical activity
smoking
excessive alcohol intake.
Osteoporosis often can be prevented. It is known as a silent disease because if undetected, bone loss can progress for many years without symptoms until a fracture occurs. Osteoporosis has been called a childhood disease with old age consequences because building healthy bones in youth helps prevent osteoporosis and fractures later in life. However, it is never too late to adopt new habits for healthy bones.
The Link Between Lactose Intolerance and Osteoporosis
One of the primary risk factors for developing osteoporosis is not getting enough calcium in your diet. Because dairy products are a major source of calcium, you might assume that people with lactose intolerance who avoid dairy products could be at increased risk for osteoporosis. However, research exploring the role of lactose intolerance in calcium intake and bone health has produced conflicting results. Some studies have found that people with lactose intolerance are at higher risk for osteoporosis, but other studies have not. Regardless, people with lactose intolerance should follow the same basic strategies to build and maintain healthy bones and should pay extra attention to getting enough calcium.
Bone Health Strategies
Calcium and vitamin D: A well-balanced diet rich in calcium and vitamin D is important for healthy bones. Besides low-fat dairy products, good sources of calcium include dark green, leafy vegetables and calcium-fortified foods and beverages. Many low-fat and low-sugar sources of calcium are available. Also, supplements can help people with lactose intolerance meet their daily requirements of calcium and other important nutrients. The Institute of Medicine recommends a daily calcium intake of 1,000 mg (milligrams) for men and women, increasing to 1,200 mg for those age 50 and older.
Studies have shown that people who have at least some intestinal lactase can increase their tolerance to lactose by gradually introducing dairy products into the diet. These people can often eat small portions of dairy products without developing symptoms. The key for them is to consume small amounts of dairy products at a time so that there is enough lactase available in the intestine to digest the lactose. When the lactose is fully digested, symptoms do not develop.
Also, certain sources of dairy products may be easier for people with lactose intolerance to digest. For example, ripened cheese may contain up to 95 percent less lactose than whole milk. Yogurt containing active cultures also lessens gastrointestinal symptoms. A variety of lactose-reduced dairy products, including milk, cottage cheese, and processed cheese slices, are also available. Lactose replacement pills and liquid are also available to help with the digestion of dairy products.
Vitamin D plays an important role in calcium absorption and bone health. It is synthesized in the skin through exposure to sunlight. Food sources of vitamin D include egg yolks, fish oil, saltwater fish, liver, fortified margarine, and breakfast cereals. Many people obtain enough vitamin D by getting about 15 minutes of sunlight each day; others, especially those who are older or housebound, may need vitamin D supplements to achieve the recommended intake of 400 to 600 IU (International Units) each day.
Exercise: Like muscle, bone is living tissue that responds to exercise by becoming stronger. The best activity for your bones is weight-bearing exercise that forces you to work against gravity. Some examples include walking, climbing stairs, weight training, and dancing. Regular exercise, such as walking, may help prevent bone loss and, by enhancing balance and flexibility, can reduce the likelihood of falling and breaking a bone.
Healthy lifestyle: Smoking is bad for bones as well as the heart and lungs. Women who smoke tend to go through menopause earlier, which triggers earlier bone loss. In addition, smokers may absorb less calcium from their diets. Alcohol also can have a negative effect on bone health. Those who drink heavily are more prone to bone loss and fracture because of both poor nutrition and increased risk of falling.
Bone density testing: A bone mineral density (BMD) test measures bone density in various parts of the body. This safe and painless test can detect osteoporosis before a bone fracture occurs and can predict one’s chances of fracturing in the future. People with lactose intolerance should talk to their doctors about whether they might be candidates for a BMD test, which can help determine whether medication should be considered.
Medication: Like lactose intolerance, osteoporosis has no cure. However, medications are available to prevent and treat osteoporosis. The Food and Drug Administration has approved several medications (alendronate, risedronate, ibandronate, zoledronic acid, raloxifene, calcitonin, teriparatide, and estrogen/hormone therapy) for the prevention and/or treatment of osteoporosis in postmenopausal women. Alendronate and risedronate are also approved for use in men. For people with or at risk for glucocorticoid-induced osteoporosis, alendronate has been approved to treat this condition and risedronate has been approved to treat and prevent it.
Resources
For more information on osteoporosis, visit the National Institutes of Health Osteoporosis and Related Bone Diseases ~ National Resource Center’s Web site at www.niams.nih.gov/bone or call 800–624–2663.
For more information on lactose intolerance, visit the National Digestive Diseases Information Clearinghouse’s Web site at http://digestive.niddk.nih.gov/index.htm or call 800–891–5389.
The National Institutes of Health Osteoporosis and Related Bone Diseases ~
National Resource Center acknowledges the assistance of the National
Osteoporosis Foundation in the preparation of this publication.
Monday, June 22, 2009
Why does milk bother me?
Why Does Milk Bother Me?
On this page:
What do I need to know about lactose intolerance?
Should I worry about lactose intolerance?
Why does my body have trouble digesting lactose?
How will I feel if I have lactose intolerance?
How will my doctor check for lactose intolerance?
What can I do about lactose intolerance?
How will I know if lactose is in food?
Can I eat any foods with lactose?
Can I take anything to help me digest lactose?
What else do I need to know about diet?
Points to Remember
What do I need to know about lactose intolerance?
Lactose intolerance means that you cannot digest foods with lactose in them. Lactose is the sugar found in milk and foods made with milk.
These foods contain lactose.
[Top]
Should I worry about lactose intolerance?
No. Lactose intolerance is not serious. You should feel better soon if you eat less food with lactose or if you use products that help you digest lactose.
Drink less milk because it has lactose in it.
[Top]
Why does my body have trouble digesting lactose?
You cannot digest lactose because you do not have enough lactase enzyme. The small intestine needs lactase enzyme to break down lactose. If lactose is not digested, it can cause gas and stomach cramps.
[Top]
How will I feel if I have lactose intolerance?
After eating foods with lactose in them, you may feel sick to your stomach.
You may also have
gas
diarrhea
swelling in your stomach
Some illnesses can cause these same problems. Your doctor can tell you if your problems are caused by lactose intolerance.
[Top]
How will my doctor check for lactose intolerance?
Your doctor might use one of these tests:
Blood and Breath Tests
You will drink a sweet drink with lactose in it. Then, your doctor will test your breath or blood for signs that you did or did not digest the lactose.
Stool Test
Your doctor can also find out if you digest lactose by testing your stool (bowel movement). The stool test is often used to check babies for lactose intolerance.
[Top]
What can I do about lactose intolerance?
You will need to eat less of all foods with lactose. These foods include the following:
Foods made with milk
Lactose is in milk and all foods made with milk, like
ice cream
ice milk
sherbet
cream
butter
some cheeses
cottage cheese
yogurt
Prepared foods
Lactose is added to some boxed, canned, frozen, and other prepared foods, like
bread
cereal
lunch meats
salad dressings
mixes for cakes, cookies, pancakes, and biscuits
frozen dinners
[Top]
How will I know if lactose is in food?
Look for certain words on food labels. These words mean the food has lactose in it:
butter
cheese
cream
dried milk
lactose
milk
milk solids
powdered milk
whey
[Top]
Can I eat any foods with lactose?
You may be able to eat a small amount of some foods with lactose. For example, you may be able to eat cheese or yogurt, but not drink milk. Aged cheeses, like cheddar and Swiss, have very little lactose. Or you may be able to eat some prepared foods. To find out if you can, try a small amount of the food and then see how you feel.
Some people can eat a little of certain foods that contain milk, but none of others.
[Top]
Can I take anything to help me digest lactose?
You can buy pills or drops at a drug or grocery store to help you digest lactose. They are
Pills that you chew right before eating foods with lactose. These pills are called lactase enzyme caplets.
A liquid that you add to milk before drinking. The liquid is called lactase enzyme drops.
You can also drink a special milk with less lactose in it. You can buy this milk at the grocery store. It is called lactose-reduced milk.
[Top]
What else do I need to know about diet?
Drinking milk and eating foods made with milk are the most common ways to get calcium. Calcium is important for good health. If you cannot eat or drink these foods, you may need to eat other foods with calcium:
canned salmon with bones
sardines
collard greens
turnip greens
broccoli
tofu
Also, ask your doctor if you should take a calcium tablet every day.
[Top]
Points to Remember
Eat fewer foods with lactose in them, like milk, some cheeses, and ice cream.
Find out if you can eat small amounts of food with lactose.
Read food labels to find out if a food has lactose in it.
Use a special pill or liquid to help you digest foods with lactose.
Eat enough foods with calcium, like broccoli.
Taking a pill to help digest lactose is one way to deal with lactose intolerance.
[Top]
--------------------------------------------------------------------------------
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.
--------------------------------------------------------------------------------
NIH Publication No. 07–2751
February 2005
On this page:
What do I need to know about lactose intolerance?
Should I worry about lactose intolerance?
Why does my body have trouble digesting lactose?
How will I feel if I have lactose intolerance?
How will my doctor check for lactose intolerance?
What can I do about lactose intolerance?
How will I know if lactose is in food?
Can I eat any foods with lactose?
Can I take anything to help me digest lactose?
What else do I need to know about diet?
Points to Remember
What do I need to know about lactose intolerance?
Lactose intolerance means that you cannot digest foods with lactose in them. Lactose is the sugar found in milk and foods made with milk.
These foods contain lactose.
[Top]
Should I worry about lactose intolerance?
No. Lactose intolerance is not serious. You should feel better soon if you eat less food with lactose or if you use products that help you digest lactose.
Drink less milk because it has lactose in it.
[Top]
Why does my body have trouble digesting lactose?
You cannot digest lactose because you do not have enough lactase enzyme. The small intestine needs lactase enzyme to break down lactose. If lactose is not digested, it can cause gas and stomach cramps.
[Top]
How will I feel if I have lactose intolerance?
After eating foods with lactose in them, you may feel sick to your stomach.
You may also have
gas
diarrhea
swelling in your stomach
Some illnesses can cause these same problems. Your doctor can tell you if your problems are caused by lactose intolerance.
[Top]
How will my doctor check for lactose intolerance?
Your doctor might use one of these tests:
Blood and Breath Tests
You will drink a sweet drink with lactose in it. Then, your doctor will test your breath or blood for signs that you did or did not digest the lactose.
Stool Test
Your doctor can also find out if you digest lactose by testing your stool (bowel movement). The stool test is often used to check babies for lactose intolerance.
[Top]
What can I do about lactose intolerance?
You will need to eat less of all foods with lactose. These foods include the following:
Foods made with milk
Lactose is in milk and all foods made with milk, like
ice cream
ice milk
sherbet
cream
butter
some cheeses
cottage cheese
yogurt
Prepared foods
Lactose is added to some boxed, canned, frozen, and other prepared foods, like
bread
cereal
lunch meats
salad dressings
mixes for cakes, cookies, pancakes, and biscuits
frozen dinners
[Top]
How will I know if lactose is in food?
Look for certain words on food labels. These words mean the food has lactose in it:
butter
cheese
cream
dried milk
lactose
milk
milk solids
powdered milk
whey
[Top]
Can I eat any foods with lactose?
You may be able to eat a small amount of some foods with lactose. For example, you may be able to eat cheese or yogurt, but not drink milk. Aged cheeses, like cheddar and Swiss, have very little lactose. Or you may be able to eat some prepared foods. To find out if you can, try a small amount of the food and then see how you feel.
Some people can eat a little of certain foods that contain milk, but none of others.
[Top]
Can I take anything to help me digest lactose?
You can buy pills or drops at a drug or grocery store to help you digest lactose. They are
Pills that you chew right before eating foods with lactose. These pills are called lactase enzyme caplets.
A liquid that you add to milk before drinking. The liquid is called lactase enzyme drops.
You can also drink a special milk with less lactose in it. You can buy this milk at the grocery store. It is called lactose-reduced milk.
[Top]
What else do I need to know about diet?
Drinking milk and eating foods made with milk are the most common ways to get calcium. Calcium is important for good health. If you cannot eat or drink these foods, you may need to eat other foods with calcium:
canned salmon with bones
sardines
collard greens
turnip greens
broccoli
tofu
Also, ask your doctor if you should take a calcium tablet every day.
[Top]
Points to Remember
Eat fewer foods with lactose in them, like milk, some cheeses, and ice cream.
Find out if you can eat small amounts of food with lactose.
Read food labels to find out if a food has lactose in it.
Use a special pill or liquid to help you digest foods with lactose.
Eat enough foods with calcium, like broccoli.
Taking a pill to help digest lactose is one way to deal with lactose intolerance.
[Top]
--------------------------------------------------------------------------------
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.
--------------------------------------------------------------------------------
NIH Publication No. 07–2751
February 2005
Lactose Intolerance
On this page:
What is lactose intolerance?
What are the symptoms of lactose intolerance?
How is lactose intolerance diagnosed?
What causes lactose intolerance?
Who is at risk for lactose intolerance?
How is lactose intolerance treated?
How is nutrition balanced?
What is hidden lactose?
Summary
For More Information
What is lactose intolerance?
Lactose intolerance is the inability to digest significant amounts of lactose, the major sugar found in milk. Lactose intolerance is caused by a shortage of the enzyme lactase, which is produced by the cells that line the small intestine. Lactase breaks down milk sugar into two simpler forms of sugar called glucose and galactose, which are then absorbed into the bloodstream. Not all people deficient in lactase have the symptoms commonly associated with lactose intolerance, but those who do are said to have lactose intolerance.
People sometimes confuse lactose intolerance with cow’s milk intolerance because the symptoms are often the same. However, lactose intolerance and cow’s milk intolerance are not related. Being intolerant to cow’s milk is an allergic reaction triggered by the immune system. Lactose intolerance is a problem caused by the digestive system.
[Top]
What are the symptoms of lactose intolerance?
People who do not have enough lactase to digest the amount of lactose they consume may feel very uncomfortable when they digest milk products. Common symptoms, which range from mild to severe, include nausea, cramps, bloating, gas, and diarrhea. Symptoms begin about 30 minutes to 2 hours after eating or drinking foods containing lactose. The severity of symptoms depends on many factors, including the amount of lactose a person can tolerate and a person’s age, ethnicity, and digestion rate.
The digestive tract
[Top]
How is lactose intolerance diagnosed?
Lactose intolerance can be hard to diagnose based on symptoms alone. People sometimes think they suffer from lactose intolerance because they have the symptoms associated with the disorder, not knowing other conditions such as irritable bowel syndrome can cause similar symptoms. A doctor can use tests to diagnose lactose intolerance but may first recommend eliminating cow’s milk from the diet to see if the symptoms go away.
The most common tests used to measure the absorption of lactose in the digestive system are the lactose tolerance, hydrogen breath, and stool acidity tests.
The Lactose Tolerance Test. This test requires fasting (not eating) before the test and then drinking a liquid that contains lactose. Several blood samples are then taken over a 2-hour period to measure the person’s blood glucose (blood sugar) level. These measures indicate how well the body is able to digest lactose.
Normally, when lactose reaches the digestive system, the lactase enzyme breaks it down into glucose and galactose. The liver then changes the galactose into glucose, which enters the bloodstream and raises the person’s blood glucose level. If, however, lactose is incompletely broken down, the blood glucose level does not rise and a diagnosis of lactose intolerance is confirmed.
The Hydrogen Breath Test. This test measures the amount of hydrogen in a person’s breath. Very little hydrogen is normally detectable. However, undigested lactose in the colon is fermented by bacteria and produces various gases, including hydrogen. The hydrogen is absorbed from the intestines, carried through the bloodstream to the lungs, and exhaled. In this test, the person drinks a lactose-loaded beverage and the breath is analyzed at regular intervals. Raised levels of hydrogen in the breath indicate improper digestion of lactose. Certain foods, medications, and cigarettes can affect the accuracy of the test and should be avoided before taking the test. People should check with their doctor to make sure they are not taking medications that may interfere with test results.
The lactose tolerance and hydrogen breath tests are not given to infants younger than 6 months of age. A large lactose load can be dangerous prior to this age, as infants are more likely to become dehydrated from diarrhea that can be caused by lactose intolerance.
Stool Acidity Test. This test may be used for infants and young children to measure the amount of acid in their stool. Undigested lactose fermented by bacteria in the colon creates lactic acid and other fatty acids that can be detected in a stool sample. Glucose may also be present in the sample as a result of unabsorbed lactose in the colon.
[Top]
What causes lactose intolerance?
Some causes of lactose intolerance are well known. Primary lactase deficiency is a condition that develops over time. After about age 2 the body begins to produce less lactase, though most people will not notice symptoms until they are much older.
Secondary lactase deficiency occurs when injury to the small intestine or certain digestive diseases reduce the amount of lactase a person produces. These diseases include celiac disease, inflammatory bowel disease, and Crohn’s disease.
Researchers have identified a genetic link for lactose intolerance. Some people are born with a likelihood of developing primary lactase deficiency because it has been passed to them genetically (inherited from their parents). This discovery may be useful in developing a diagnostic test to identify people with the condition.
[Top]
Who is at risk for lactose intolerance?
Between 30 and 50 million Americans are lactose intolerant and certain ethnic and racial populations are more affected than others. Up to 80 percent of African Americans, 80 to 100 percent of American Indians, and 90 to 100 percent of Asian Americans are lactose intolerant. The condition is least common among people of northern European descent.
Babies that are born prematurely are also more likely to be lactose intolerant, because lactase levels do not increase until the third trimester of a woman’s pregnancy.
[Top]
How is lactose intolerance treated?
Lactose intolerance is easy to treat. No treatment can improve the body’s ability to produce lactase, but symptoms can be controlled through diet.
Young children and infants with lactase deficiency should not consume lactose-containing formulas or foods until they are able to tolerate lactose digestion. Most older children and adults do not have to avoid lactose completely, but people differ in the amounts and types of foods they can handle. For example, one person may have symptoms after drinking a small glass of milk, while another can drink one glass but not two. Others may be able to manage ice cream and aged cheeses, such as cheddar and Swiss, but not other dairy products. People can also tolerate more lactose by having smaller amounts of it at one time. The level of dietary control needed with lactose intolerance depends on how much lactose a person’s body can handle.
For those who react to very small amounts of lactose or have trouble limiting their intake of foods that contain it, the lactase enzyme is available without a prescription to help people digest foods that contain lactose. The tablets are taken with the first bite of dairy food. Lactase enzyme is also available as a liquid. Adding a few drops of the enzyme makes lactose more digestible for people with lactose intolerance.
Lactose-reduced milk and other products are available at most supermarkets. The milk contains all of the nutrients found in regular milk and remains fresh for about the same length of time, or longer if it is super-pasteurized.
[Top]
How is nutrition balanced?
Milk and other dairy products are a major source of nutrients in the American diet. One of the most important of these nutrients is calcium. Calcium is essential for the growth and repair of bones throughout life. In the middle and later years, a shortage of calcium may lead to thin, fragile bones that break easily, a condition called osteoporosis. A concern for both children and adults with lactose intolerance is getting enough calcium in a diet that includes little or no dairy products.
The Institute of Medicine released a report listing the requirements for daily calcium intake. How much calcium a person needs to maintain good health varies by age group. Recommendations from the report are shown in the following table.
Age group Amount of calcium
to consume daily,
in milligrams (mg)
0–6 months 400 mg
6–12 months 600 mg
1–5 years 800 mg
6–10 years 1,200 mg
11–24 years 1,200–1,500 mg
19–50 years 1,000 mg
51–70+ years 1,500 mg
In addition, pregnant and nursing women need between 1,200 and 1,500 mg of calcium daily.
In planning meals, people with lactose intolerance should make sure that each day’s diet includes enough calcium, even if dairy products are not included. Many non-dairy foods are high in calcium, including dark green vegetables such as broccoli, or fish with soft, edible bones, such as salmon and sardines. To help in planning a high-calcium, low-lactose diet, the table that follows lists some common foods that are good sources of dietary calcium and shows how much lactose they contain.
Recent research shows that yogurt with active cultures may be a good source of calcium for many people with lactose intolerance. Even though yogurt is fairly high in lactose, the bacterial cultures used to make it produce some of the lactase enzyme required for proper digestion.
Clearly, many foods can provide the calcium and other nutrients the body needs, even when intake of milk and dairy products is limited. However, factors other than calcium and lactose content should be kept in mind when planning a diet. Some vegetables that are high in calcium (Swiss chard, spinach, and rhubarb, for example) are not listed in the chart because the body cannot use the calcium they contain because these foods also contain substances called oxalates, which stop calcium absorption.
Calcium and Lactose in Common Foods
Nondairy Products Calcium Content Lactose Content
Soymilk, fortified, 1 cup 200–300 mg 0
Sardines, with edible bones, 3 oz. 270 mg 0
Salmon, canned, with edible bones, 3 oz. 205 mg 0
Broccoli, raw, 1 cup 90 mg 0
Orange, 1 medium 50 mg 0
Pinto beans, 1/2 cup 40 mg 0
Tuna, canned, 3 oz. 10 mg 0
Lettuce greens, 1/2 cup 10 mg 0
Dairy Products
Yogurt, plain, low-fat, 1 cup 415 mg 5 g
Milk, reduced fat, 1 cup 295 mg 11 g
Swiss cheese, 1 oz. 270 mg 1 g
Ice cream, 1/2 cup 85 mg 6 g
Cottage cheese, 1/2 cup 75 mg 2–3 g
Adapted from Manual of Clinical Dietetics. 6th ed. American Dietetic Association, 2000; and Soy Dairy Alternatives.
Available at: www.soyfoods.org.
Calcium is absorbed and used only when there is enough vitamin D in the body. A balanced diet should provide an adequate supply of vitamin D from sources such as eggs and liver. Sunlight also helps the body naturally absorb vitamin D, and with enough exposure to the sun, food sources may not be necessary.
Some people with lactose intolerance may think they are not getting enough calcium and vitamin D in their diet. Consultation with a doctor or dietitian may be helpful in deciding whether dietary supplements are needed. Taking vitamins or minerals of the wrong kind or in the wrong amounts can be harmful. A dietitian can help plan meals that will provide the most nutrients with the least chance of causing discomfort.
[Top]
What is hidden lactose?
Although milk and foods made from milk are the only natural sources of lactose, it is often added to prepared foods. People with very low tolerance for lactose should know about the many food products that may contain even small amounts of lactose, such as
bread and other baked goods
processed breakfast cereals
instant potatoes, soups, and breakfast drinks
margarine
lunch meats (other than kosher)
salad dressings
candies and other snacks
mixes for pancakes, biscuits, and cookies
powdered meal-replacement supplements
Some products labeled non-dairy, such as powdered coffee creamer and whipped toppings, may actually include ingredients that are derived from milk and therefore contain lactose.
Learn to read food labels with care, looking not only for milk and lactose, but also for words such as whey, curds, milk by-products, dry milk solids, and non-fat dry milk powder. If any of these words are listed on a label, the product contains lactose.
Lactose is also used in more than 20 percent of prescription drugs and about 6 percent of over-the-counter medicines. Many types of birth control pills contain lactose, as do some tablets for stomach acid and gas. However, these products typically affect only people with severe lactose intolerance.
[Top]
Summary
Even though lactose intolerance is common, it is not a threat to good health. People who have trouble digesting lactose can learn which dairy products and other foods they can eat without discomfort and which ones they should avoid. Many people can enjoy milk, ice cream, and other such products if they eat them in small amounts or eat other food at the same time. Others can use lactase liquid or tablets to help digest the lactose. Even older women at risk for osteoporosis and growing children who must avoid milk and foods made with milk can meet most of their dietary needs by eating greens, fish, and other calcium-rich foods that are free of lactose. A carefully chosen diet, with calcium supplements if the doctor or dietitian recommends them, is the key to reducing symptoms.
[Top]
For More Information
American Dietetic Association (ADA)
120 South Riverside Plaza
Suite 2000
Chicago, IL 60606–6995
Phone: 1–800–877–1600
Fax: 312–899–4899
Internet: www.eatright.org
International Foundation for Functional Gastrointestinal Disorders (IFFGD) Inc.
P.O. Box 170864
Milwaukee, WI 53217
Phone: 1–888–964–2001 or 414–964–1799
Fax: 414–964–7176
Email: iffgd@iffgd.org
Internet: www.iffgd.org
--------------------------------------------------------------------------------
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.
Publications produced by the Clearinghouse are carefully reviewed by both NIDDK scientists and outside experts. This publication was reviewed by Eric Sibley, M.D., Ph.D., Stanford University School of Medicine.
This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired.
On this page:
What is lactose intolerance?
What are the symptoms of lactose intolerance?
How is lactose intolerance diagnosed?
What causes lactose intolerance?
Who is at risk for lactose intolerance?
How is lactose intolerance treated?
How is nutrition balanced?
What is hidden lactose?
Summary
For More Information
What is lactose intolerance?
Lactose intolerance is the inability to digest significant amounts of lactose, the major sugar found in milk. Lactose intolerance is caused by a shortage of the enzyme lactase, which is produced by the cells that line the small intestine. Lactase breaks down milk sugar into two simpler forms of sugar called glucose and galactose, which are then absorbed into the bloodstream. Not all people deficient in lactase have the symptoms commonly associated with lactose intolerance, but those who do are said to have lactose intolerance.
People sometimes confuse lactose intolerance with cow’s milk intolerance because the symptoms are often the same. However, lactose intolerance and cow’s milk intolerance are not related. Being intolerant to cow’s milk is an allergic reaction triggered by the immune system. Lactose intolerance is a problem caused by the digestive system.
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What are the symptoms of lactose intolerance?
People who do not have enough lactase to digest the amount of lactose they consume may feel very uncomfortable when they digest milk products. Common symptoms, which range from mild to severe, include nausea, cramps, bloating, gas, and diarrhea. Symptoms begin about 30 minutes to 2 hours after eating or drinking foods containing lactose. The severity of symptoms depends on many factors, including the amount of lactose a person can tolerate and a person’s age, ethnicity, and digestion rate.
The digestive tract
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How is lactose intolerance diagnosed?
Lactose intolerance can be hard to diagnose based on symptoms alone. People sometimes think they suffer from lactose intolerance because they have the symptoms associated with the disorder, not knowing other conditions such as irritable bowel syndrome can cause similar symptoms. A doctor can use tests to diagnose lactose intolerance but may first recommend eliminating cow’s milk from the diet to see if the symptoms go away.
The most common tests used to measure the absorption of lactose in the digestive system are the lactose tolerance, hydrogen breath, and stool acidity tests.
The Lactose Tolerance Test. This test requires fasting (not eating) before the test and then drinking a liquid that contains lactose. Several blood samples are then taken over a 2-hour period to measure the person’s blood glucose (blood sugar) level. These measures indicate how well the body is able to digest lactose.
Normally, when lactose reaches the digestive system, the lactase enzyme breaks it down into glucose and galactose. The liver then changes the galactose into glucose, which enters the bloodstream and raises the person’s blood glucose level. If, however, lactose is incompletely broken down, the blood glucose level does not rise and a diagnosis of lactose intolerance is confirmed.
The Hydrogen Breath Test. This test measures the amount of hydrogen in a person’s breath. Very little hydrogen is normally detectable. However, undigested lactose in the colon is fermented by bacteria and produces various gases, including hydrogen. The hydrogen is absorbed from the intestines, carried through the bloodstream to the lungs, and exhaled. In this test, the person drinks a lactose-loaded beverage and the breath is analyzed at regular intervals. Raised levels of hydrogen in the breath indicate improper digestion of lactose. Certain foods, medications, and cigarettes can affect the accuracy of the test and should be avoided before taking the test. People should check with their doctor to make sure they are not taking medications that may interfere with test results.
The lactose tolerance and hydrogen breath tests are not given to infants younger than 6 months of age. A large lactose load can be dangerous prior to this age, as infants are more likely to become dehydrated from diarrhea that can be caused by lactose intolerance.
Stool Acidity Test. This test may be used for infants and young children to measure the amount of acid in their stool. Undigested lactose fermented by bacteria in the colon creates lactic acid and other fatty acids that can be detected in a stool sample. Glucose may also be present in the sample as a result of unabsorbed lactose in the colon.
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What causes lactose intolerance?
Some causes of lactose intolerance are well known. Primary lactase deficiency is a condition that develops over time. After about age 2 the body begins to produce less lactase, though most people will not notice symptoms until they are much older.
Secondary lactase deficiency occurs when injury to the small intestine or certain digestive diseases reduce the amount of lactase a person produces. These diseases include celiac disease, inflammatory bowel disease, and Crohn’s disease.
Researchers have identified a genetic link for lactose intolerance. Some people are born with a likelihood of developing primary lactase deficiency because it has been passed to them genetically (inherited from their parents). This discovery may be useful in developing a diagnostic test to identify people with the condition.
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Who is at risk for lactose intolerance?
Between 30 and 50 million Americans are lactose intolerant and certain ethnic and racial populations are more affected than others. Up to 80 percent of African Americans, 80 to 100 percent of American Indians, and 90 to 100 percent of Asian Americans are lactose intolerant. The condition is least common among people of northern European descent.
Babies that are born prematurely are also more likely to be lactose intolerant, because lactase levels do not increase until the third trimester of a woman’s pregnancy.
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How is lactose intolerance treated?
Lactose intolerance is easy to treat. No treatment can improve the body’s ability to produce lactase, but symptoms can be controlled through diet.
Young children and infants with lactase deficiency should not consume lactose-containing formulas or foods until they are able to tolerate lactose digestion. Most older children and adults do not have to avoid lactose completely, but people differ in the amounts and types of foods they can handle. For example, one person may have symptoms after drinking a small glass of milk, while another can drink one glass but not two. Others may be able to manage ice cream and aged cheeses, such as cheddar and Swiss, but not other dairy products. People can also tolerate more lactose by having smaller amounts of it at one time. The level of dietary control needed with lactose intolerance depends on how much lactose a person’s body can handle.
For those who react to very small amounts of lactose or have trouble limiting their intake of foods that contain it, the lactase enzyme is available without a prescription to help people digest foods that contain lactose. The tablets are taken with the first bite of dairy food. Lactase enzyme is also available as a liquid. Adding a few drops of the enzyme makes lactose more digestible for people with lactose intolerance.
Lactose-reduced milk and other products are available at most supermarkets. The milk contains all of the nutrients found in regular milk and remains fresh for about the same length of time, or longer if it is super-pasteurized.
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How is nutrition balanced?
Milk and other dairy products are a major source of nutrients in the American diet. One of the most important of these nutrients is calcium. Calcium is essential for the growth and repair of bones throughout life. In the middle and later years, a shortage of calcium may lead to thin, fragile bones that break easily, a condition called osteoporosis. A concern for both children and adults with lactose intolerance is getting enough calcium in a diet that includes little or no dairy products.
The Institute of Medicine released a report listing the requirements for daily calcium intake. How much calcium a person needs to maintain good health varies by age group. Recommendations from the report are shown in the following table.
Age group Amount of calcium
to consume daily,
in milligrams (mg)
0–6 months 400 mg
6–12 months 600 mg
1–5 years 800 mg
6–10 years 1,200 mg
11–24 years 1,200–1,500 mg
19–50 years 1,000 mg
51–70+ years 1,500 mg
In addition, pregnant and nursing women need between 1,200 and 1,500 mg of calcium daily.
In planning meals, people with lactose intolerance should make sure that each day’s diet includes enough calcium, even if dairy products are not included. Many non-dairy foods are high in calcium, including dark green vegetables such as broccoli, or fish with soft, edible bones, such as salmon and sardines. To help in planning a high-calcium, low-lactose diet, the table that follows lists some common foods that are good sources of dietary calcium and shows how much lactose they contain.
Recent research shows that yogurt with active cultures may be a good source of calcium for many people with lactose intolerance. Even though yogurt is fairly high in lactose, the bacterial cultures used to make it produce some of the lactase enzyme required for proper digestion.
Clearly, many foods can provide the calcium and other nutrients the body needs, even when intake of milk and dairy products is limited. However, factors other than calcium and lactose content should be kept in mind when planning a diet. Some vegetables that are high in calcium (Swiss chard, spinach, and rhubarb, for example) are not listed in the chart because the body cannot use the calcium they contain because these foods also contain substances called oxalates, which stop calcium absorption.
Calcium and Lactose in Common Foods
Nondairy Products Calcium Content Lactose Content
Soymilk, fortified, 1 cup 200–300 mg 0
Sardines, with edible bones, 3 oz. 270 mg 0
Salmon, canned, with edible bones, 3 oz. 205 mg 0
Broccoli, raw, 1 cup 90 mg 0
Orange, 1 medium 50 mg 0
Pinto beans, 1/2 cup 40 mg 0
Tuna, canned, 3 oz. 10 mg 0
Lettuce greens, 1/2 cup 10 mg 0
Dairy Products
Yogurt, plain, low-fat, 1 cup 415 mg 5 g
Milk, reduced fat, 1 cup 295 mg 11 g
Swiss cheese, 1 oz. 270 mg 1 g
Ice cream, 1/2 cup 85 mg 6 g
Cottage cheese, 1/2 cup 75 mg 2–3 g
Adapted from Manual of Clinical Dietetics. 6th ed. American Dietetic Association, 2000; and Soy Dairy Alternatives.
Available at: www.soyfoods.org.
Calcium is absorbed and used only when there is enough vitamin D in the body. A balanced diet should provide an adequate supply of vitamin D from sources such as eggs and liver. Sunlight also helps the body naturally absorb vitamin D, and with enough exposure to the sun, food sources may not be necessary.
Some people with lactose intolerance may think they are not getting enough calcium and vitamin D in their diet. Consultation with a doctor or dietitian may be helpful in deciding whether dietary supplements are needed. Taking vitamins or minerals of the wrong kind or in the wrong amounts can be harmful. A dietitian can help plan meals that will provide the most nutrients with the least chance of causing discomfort.
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What is hidden lactose?
Although milk and foods made from milk are the only natural sources of lactose, it is often added to prepared foods. People with very low tolerance for lactose should know about the many food products that may contain even small amounts of lactose, such as
bread and other baked goods
processed breakfast cereals
instant potatoes, soups, and breakfast drinks
margarine
lunch meats (other than kosher)
salad dressings
candies and other snacks
mixes for pancakes, biscuits, and cookies
powdered meal-replacement supplements
Some products labeled non-dairy, such as powdered coffee creamer and whipped toppings, may actually include ingredients that are derived from milk and therefore contain lactose.
Learn to read food labels with care, looking not only for milk and lactose, but also for words such as whey, curds, milk by-products, dry milk solids, and non-fat dry milk powder. If any of these words are listed on a label, the product contains lactose.
Lactose is also used in more than 20 percent of prescription drugs and about 6 percent of over-the-counter medicines. Many types of birth control pills contain lactose, as do some tablets for stomach acid and gas. However, these products typically affect only people with severe lactose intolerance.
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Summary
Even though lactose intolerance is common, it is not a threat to good health. People who have trouble digesting lactose can learn which dairy products and other foods they can eat without discomfort and which ones they should avoid. Many people can enjoy milk, ice cream, and other such products if they eat them in small amounts or eat other food at the same time. Others can use lactase liquid or tablets to help digest the lactose. Even older women at risk for osteoporosis and growing children who must avoid milk and foods made with milk can meet most of their dietary needs by eating greens, fish, and other calcium-rich foods that are free of lactose. A carefully chosen diet, with calcium supplements if the doctor or dietitian recommends them, is the key to reducing symptoms.
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For More Information
American Dietetic Association (ADA)
120 South Riverside Plaza
Suite 2000
Chicago, IL 60606–6995
Phone: 1–800–877–1600
Fax: 312–899–4899
Internet: www.eatright.org
International Foundation for Functional Gastrointestinal Disorders (IFFGD) Inc.
P.O. Box 170864
Milwaukee, WI 53217
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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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.
Publications produced by the Clearinghouse are carefully reviewed by both NIDDK scientists and outside experts. This publication was reviewed by Eric Sibley, M.D., Ph.D., Stanford University School of Medicine.
This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired.
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