Table of ContentsView AllTable of ContentsSymptomsCausesTriggersLactose Intolerance or Dairy Allergy?DiagnosisTreatmentComplications

Table of ContentsView All

View All

Table of Contents

Symptoms

Causes

Triggers

Lactose Intolerance or Dairy Allergy?

Diagnosis

Treatment

Complications

When you don’t have enough of the digestive enzyme lactase to digest the lactose in dairy, you can experience abdominal discomfort and digestive issues after eating products like milk, ice cream, yogurt, and cheese. This is known aslactose intolerance.

Lactose is the natural sugar in milk and dairy foods. Your small intestine produces anenzymecalled lactase to break this sugar down for digestion.

This article discusses the causes and symptoms of lactose intolerance, how it is diagnosed, and different options for managing the condition.

1:59Click Play to Learn All About Lactose Intolerance

1:59

Click Play to Learn All About Lactose Intolerance

Lactose Intolerance Symptoms

Worldwide, upwards of 70% of adults are lactose intolerant. It’s uncommon for children under 5 to have the condition.Lactose intolerance symptoms in adults, which occur only after lactose is consumed, may include:

These symptoms usually occur half an hour to a couple of hours after eating dairy products.Typically, the severity of symptoms corresponds with how much of the offending food and/or drink was consumed.

While classic lactose intolerance symptoms are present, these are fairly general symptoms that may also occur because of several other conditions.

Causes of Lactose Intolerance

For some, a naturally occurring bacteria called lactic acid bacteria can take over for the missing lactase. But even with that present, that may not be enough to digest lactose.

This causes fluid to flow into your colon, where bacteria feed on it and causes symptoms of lactose intolerance, such as diarrhea and stomach cramps. It is only after this that it eventually leaves the body in feces.

The decrease in the lactase enzyme, called lactose non-persistence, is the most common cause of lactose intolerance.

Genetics is the least common cause. Parents may pass an intolerance onto a child, in which case the condition may begin from birth.Infants with this condition may be unable to digest breast milk and require a lactose-free formula.

Others may experience lactose intolerance due to a digestive disorder. Conditions such asCrohn’s diseaseorceliac diseasecan damage the intestinal cells that produce lactase.

Sudden Lactose Intolerance

For many people, the condition seems to come on suddenly, even if they never had a problem with eating or drinking products with lactose before.

Does Protein Make You Poop?

Lactose Intolerance In Children

Though it’s most common in adults, lactose intolerance can also affect children as early as age 2. If you have a child with lactose intolerance, it can be a problem throughout their life, or they may outgrow it.

The symptoms of lactose intolerance in children are the same as those in adults. You may also notice that your child is cranky or has mood swings after they consume dairy products due to the discomfort they feel.

Keep in mind that breastmilk and infant formula made with cow’s milk both contain lactose. If your infant consistently becomes cranky and has symptoms of lactose intolerance after being fed one of these, see their pediatrician.

Foods That Trigger Lactose Intolerance

Since lactose is the natural sugar found in milk, cheese, and other dairy products, a person with lactose intolerance will experience symptoms any time they consume one of those products.

Foods that commonly trigger lactose intolerance include:

Some people may experience lactose intolerance from consuming certain foods but not others.

A dairy allergy is not the same as lactose intolerance. With dairy allergy, the immune system works to fight the proteins in milk, even though they are not inherently harmful.

Symptoms of dairy allergy are different from those of lactose intolerance. If you or your child has anallergic reactionto a dairy product, call 911 or go to the hospital immediately.

Symptoms of dairy allergy include:

Do I Have a Milk Allergy? Here’s How to Tell

Diagnosing Lactose Intolerance

If you experience symptoms of lactose intolerance, it is best to speak with your healthcare provider to get a formal diagnosis and advice that is tailored specifically to your health and medical needs.

Many people determine that they or their child has lactose intolerance simply because they experience symptoms after consuming dairy. While your assumption may prove true, remember that other medical problems can produce similar symptoms. Examples include infection, inflammatory bowel disease, malabsorption, and food allergy.

Elimination Diet

Anelimination dietmay help diagnose lactose intolerance.With this, you eliminate all dairy products to see if the symptoms resolve.

It is important to eliminate only dairy when doing this. Otherwise, you won’t be as certain about what foods trigger your symptoms.

Some of the richest non-dairy sources of calcium include:Calcium-fortified foods and beverages, such as orange juice, soy milk, cereals, and breadCanned fishwith bones, such as sardines and salmonLeafy green vegetables, including broccoli, kale, and Chinese cabbageMilk substitutes such as soy and nut beveragesDietary supplements with calcium

Some of the richest non-dairy sources of calcium include:

Diagnostic Tests

Treatment of Lactose Intolerance

Treatment for lactose intolerance consists of avoiding some or all lactose-containing foods or supplementing your body’s supply of lactase enzyme to better digest dairy if you consume it.

When an underlying condition causes lactose intolerance in a child, treating the condition will typically resolve the symptoms within three to four weeks.

Adults are less likely to “cure” their intolerance. Lactase levels can be restored in adults, but the process can take some time and is not always possible. Treatment, therefore, is focused on management.

Diet Changes

You may find that cutting out all dairy makes you feel your best. However, this may not be necessary for everyone.

You may notice that you can tolerate cheese but not ice cream or yogurt but not milk, for example.It is perfectly fine to consume the foods and drinks that don’t cause you problems while avoiding the products that do.

It’s worth mentioning your diet changes to your healthcare provider so they can check for possible nutrient deficiencies resulting from eliminating foods.

If calcium is a concern, know you can also get this vital nutrient from non-dairy sources, including fortified cereals and orange juice, kale, collard greens, garbanzo beans, and cooked broccoli.

Lactose-free milk and lactose-free ice cream are available in most grocery stores. Like regular milk, these also contain calcium and vitamin D. Most people who have lactose intolerance do not experience symptoms when consuming these lactose-free dairy options.

Supplements

Over-the-counterlactase enzyme supplementscan be taken before eating dairy products, but they are only effective if you get the timing right. Be sure to follow the package directions when taking these to have the beneficial effects when needed.

Probiotics—helpful bacteria that naturally live in thedigestive tract—may also help ease symptoms in some people with lactose intolerance.

What Is Probiotic Acidophilus?

Complications of Lactose Intolerance

If you have severe lactose intolerance, some complications can occur. Frequent vomiting or diarrhea can causedehydration, weight loss, or imbalances inelectrolytes—particles that have several roles in the body, including helping your muscles contract and your nerves send signals.

If you have a gastrointestinal (GI) infection, the effects of your lactose intolerance can be more noticeable until the infection resolves. If you have a GI condition such asinflammatory bowel diseaseorirritable bowel syndrome, it can make your lactose intolerance worse.

Some people who have lactose intolerance avoid all dairy products. As a result, they can become deficient in essential nutrients such ascalcium,vitamin D, and protein.

These deficiencies can cause several health effects, such as bone fragility.

Summary

When you are an infant, your body creates the enzyme lactase, which breaks down lactose—the sugar found naturally in milk and other dairy products. Your body stops making lactase after you are 2 to 5 years old, which is why lactose intolerance becomes more common as you age.

Lactose intolerance symptoms like diarrhea, gas, and bloating can begin a half hour or more after consuming a food or drink that contains lactose.

16 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Bayless TM, Brown E, Paige DM.Lactase non-persistence and lactose intolerance.Curr Gastroenterol Rep. 2017;19(5):23. doi:10.1007/s11894-017-0558-9Cedars Sinai.Lactose intolerance.MedlinePlus.Lactose intolerance.KidsHealth from Nemours.Lactose intolerance.National Institutes of Health.Lactose Intolerance.Deng Y, Misselwitz B, Dai N, Fox M.Lactose intolerance in adults: Biological mechanism and dietary management.Nutrients. 2015;7(9):8020-8035. doi:10.3390/nu7095380Szilagyi A, Ishayek N.Lactose intolerance, dairy avoidance, and treatment options.Nutrients. 2018 Dec;10(12):1994. doi:10.3390/nu10121994UW Integrative Health. School of Medicine and Public Health University of Wisconsin Madison.The elimination diet.National Institutes of Health Office of Dietary Supplements.Calcium.Johns Hopkins Medicine.Lactose intolerance.American College of Gastroenterology.Lactose intolerance.Dekker PJT, Koenders D, Bruins MJ.Lactose-free dairy products: Market developments, production, nutrition and health benefits.Nutrients. 2019;11(3). doi:10.3390/nu11030551Mayo Clinic.Calcium and calcium supplements: Achieving the right balance.Ferreira-lazarte A, Moreno FJ, Villamiel M.Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management.Food Funct. 2018;9(9):4642-4650.  doi:10.1039/c8fo01091aBorghini R, Donato G, Alvaro D, Picarelli A.New insights in IBS-like disorders: Pandora’s box has been opened; a review.Gastroenterol Hepatol Bed Bench. 2017;10(2):79-89.Szilagyi A, Ishayek N.Lactose intolerance, dairy avoidance, and treatment options.Nutrients. 2018;10(12). doi:10.3390/nu10121994Additional ReadingFerreira-Lazarte A , Moreno FJ , Villamiel M.Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management.Food Funct. 2018 Sep 19;9(9):4642-4650. doi:10.1039/c8fo01091aVarjú P, Gede N, Szakács Z, Hegyi P, Cazacu IM, Pécsi D et al.Lactose intolerance but not lactose maldigestion is more frequent in patients with irritable bowel syndrome than in healthy controls: A meta-analysis.Neurogastroenterol Motil. 2019 May;31(5):e13527. doi:10.1111/nmo.13527

16 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Bayless TM, Brown E, Paige DM.Lactase non-persistence and lactose intolerance.Curr Gastroenterol Rep. 2017;19(5):23. doi:10.1007/s11894-017-0558-9Cedars Sinai.Lactose intolerance.MedlinePlus.Lactose intolerance.KidsHealth from Nemours.Lactose intolerance.National Institutes of Health.Lactose Intolerance.Deng Y, Misselwitz B, Dai N, Fox M.Lactose intolerance in adults: Biological mechanism and dietary management.Nutrients. 2015;7(9):8020-8035. doi:10.3390/nu7095380Szilagyi A, Ishayek N.Lactose intolerance, dairy avoidance, and treatment options.Nutrients. 2018 Dec;10(12):1994. doi:10.3390/nu10121994UW Integrative Health. School of Medicine and Public Health University of Wisconsin Madison.The elimination diet.National Institutes of Health Office of Dietary Supplements.Calcium.Johns Hopkins Medicine.Lactose intolerance.American College of Gastroenterology.Lactose intolerance.Dekker PJT, Koenders D, Bruins MJ.Lactose-free dairy products: Market developments, production, nutrition and health benefits.Nutrients. 2019;11(3). doi:10.3390/nu11030551Mayo Clinic.Calcium and calcium supplements: Achieving the right balance.Ferreira-lazarte A, Moreno FJ, Villamiel M.Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management.Food Funct. 2018;9(9):4642-4650.  doi:10.1039/c8fo01091aBorghini R, Donato G, Alvaro D, Picarelli A.New insights in IBS-like disorders: Pandora’s box has been opened; a review.Gastroenterol Hepatol Bed Bench. 2017;10(2):79-89.Szilagyi A, Ishayek N.Lactose intolerance, dairy avoidance, and treatment options.Nutrients. 2018;10(12). doi:10.3390/nu10121994Additional ReadingFerreira-Lazarte A , Moreno FJ , Villamiel M.Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management.Food Funct. 2018 Sep 19;9(9):4642-4650. doi:10.1039/c8fo01091aVarjú P, Gede N, Szakács Z, Hegyi P, Cazacu IM, Pécsi D et al.Lactose intolerance but not lactose maldigestion is more frequent in patients with irritable bowel syndrome than in healthy controls: A meta-analysis.Neurogastroenterol Motil. 2019 May;31(5):e13527. doi:10.1111/nmo.13527

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Bayless TM, Brown E, Paige DM.Lactase non-persistence and lactose intolerance.Curr Gastroenterol Rep. 2017;19(5):23. doi:10.1007/s11894-017-0558-9Cedars Sinai.Lactose intolerance.MedlinePlus.Lactose intolerance.KidsHealth from Nemours.Lactose intolerance.National Institutes of Health.Lactose Intolerance.Deng Y, Misselwitz B, Dai N, Fox M.Lactose intolerance in adults: Biological mechanism and dietary management.Nutrients. 2015;7(9):8020-8035. doi:10.3390/nu7095380Szilagyi A, Ishayek N.Lactose intolerance, dairy avoidance, and treatment options.Nutrients. 2018 Dec;10(12):1994. doi:10.3390/nu10121994UW Integrative Health. School of Medicine and Public Health University of Wisconsin Madison.The elimination diet.National Institutes of Health Office of Dietary Supplements.Calcium.Johns Hopkins Medicine.Lactose intolerance.American College of Gastroenterology.Lactose intolerance.Dekker PJT, Koenders D, Bruins MJ.Lactose-free dairy products: Market developments, production, nutrition and health benefits.Nutrients. 2019;11(3). doi:10.3390/nu11030551Mayo Clinic.Calcium and calcium supplements: Achieving the right balance.Ferreira-lazarte A, Moreno FJ, Villamiel M.Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management.Food Funct. 2018;9(9):4642-4650.  doi:10.1039/c8fo01091aBorghini R, Donato G, Alvaro D, Picarelli A.New insights in IBS-like disorders: Pandora’s box has been opened; a review.Gastroenterol Hepatol Bed Bench. 2017;10(2):79-89.Szilagyi A, Ishayek N.Lactose intolerance, dairy avoidance, and treatment options.Nutrients. 2018;10(12). doi:10.3390/nu10121994

Bayless TM, Brown E, Paige DM.Lactase non-persistence and lactose intolerance.Curr Gastroenterol Rep. 2017;19(5):23. doi:10.1007/s11894-017-0558-9

Cedars Sinai.Lactose intolerance.

MedlinePlus.Lactose intolerance.

KidsHealth from Nemours.Lactose intolerance.

National Institutes of Health.Lactose Intolerance.

Deng Y, Misselwitz B, Dai N, Fox M.Lactose intolerance in adults: Biological mechanism and dietary management.Nutrients. 2015;7(9):8020-8035. doi:10.3390/nu7095380

Szilagyi A, Ishayek N.Lactose intolerance, dairy avoidance, and treatment options.Nutrients. 2018 Dec;10(12):1994. doi:10.3390/nu10121994

UW Integrative Health. School of Medicine and Public Health University of Wisconsin Madison.The elimination diet.

National Institutes of Health Office of Dietary Supplements.Calcium.

Johns Hopkins Medicine.Lactose intolerance.

American College of Gastroenterology.Lactose intolerance.

Dekker PJT, Koenders D, Bruins MJ.Lactose-free dairy products: Market developments, production, nutrition and health benefits.Nutrients. 2019;11(3). doi:10.3390/nu11030551

Mayo Clinic.Calcium and calcium supplements: Achieving the right balance.

Ferreira-lazarte A, Moreno FJ, Villamiel M.Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management.Food Funct. 2018;9(9):4642-4650.  doi:10.1039/c8fo01091a

Borghini R, Donato G, Alvaro D, Picarelli A.New insights in IBS-like disorders: Pandora’s box has been opened; a review.Gastroenterol Hepatol Bed Bench. 2017;10(2):79-89.

Szilagyi A, Ishayek N.Lactose intolerance, dairy avoidance, and treatment options.Nutrients. 2018;10(12). doi:10.3390/nu10121994

Ferreira-Lazarte A , Moreno FJ , Villamiel M.Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management.Food Funct. 2018 Sep 19;9(9):4642-4650. doi:10.1039/c8fo01091aVarjú P, Gede N, Szakács Z, Hegyi P, Cazacu IM, Pécsi D et al.Lactose intolerance but not lactose maldigestion is more frequent in patients with irritable bowel syndrome than in healthy controls: A meta-analysis.Neurogastroenterol Motil. 2019 May;31(5):e13527. doi:10.1111/nmo.13527

Ferreira-Lazarte A , Moreno FJ , Villamiel M.Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management.Food Funct. 2018 Sep 19;9(9):4642-4650. doi:10.1039/c8fo01091a

Varjú P, Gede N, Szakács Z, Hegyi P, Cazacu IM, Pécsi D et al.Lactose intolerance but not lactose maldigestion is more frequent in patients with irritable bowel syndrome than in healthy controls: A meta-analysis.Neurogastroenterol Motil. 2019 May;31(5):e13527. doi:10.1111/nmo.13527

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