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Acquired lactose intolerance: Lactose intolerance – Symptoms and causes


Lactose Intolerance – American College of Gastroenterology


Lactose is a natural sugar found in milk and dairy products such as cheese and yogurt. After eating this sugar, a digestive enzyme called lactase helps to breakdown lactase into two simple sugars, glucose and galactose for digestion. These simple sugars are then absorbed in the small intestine and ultimately reach the blood stream where they act as nutrients. The enzyme lactase is in the lining of the small intestine known as the intestinal villi.

In addition to milk and dairy products such as cream, ice cream, yogurt and cheese, lactose can be found in bread and baked goods, processed breakfast cereals, instant potatoes, some soups and non-kosher lunch meats, candies, dressings and mixes for pancakes and biscuits. Lactose is also the sugar found in breast milk and standard infant formulas and serves as their primary dietary sugar.


In those who are lactose intolerant, lactose is not able to be properly digested in the small intestine. Instead, it passes undigested into the colon (large intestine). Upon reaching the colon, it is broken down by the normal colon bacteria in a process called fermentation. This breakdown results in the production of carbon dioxide and hydrogen gases, organic acids, and other molecules leading to the following common symptoms:

  • Abdominal distension called bloating
  • Abdominal cramping or

  • Abdominal cramping or pain
  • Excess burping
  • Loud bowel sounds
  • Excess gas
  • Diarrhea with watery or explosive bowel movements
  • Sudden urge to have a bowel movement

The symptoms of lactose intolerance can start during childhood or adolescence and tend to get worse with age, though many people do not develop symptoms until later in life. The severity of symptoms is usually proportional to the amount of the milk sugar ingested with more symptoms following a meal with higher milk sugar content.

Although eating lactose-containing products will result in discomfort for someone who is lactose intolerant, they are not at risk of developing more serious intestinal disease because of long-term lactose malabsorption. The only exception to this would be for babies who are born with primary lactase deficiency or children with secondary lactase deficiency as discussed below.


Primary Lactase Deficiency: This condition is very rare and occurs when babies are born with a deficiency or absence of the enzyme lactase. Babies inherit this condition by getting one gene that causes this problem from each of their parents, even though both parents may be lactose tolerant. These babies require a specialized formula with another type of sugar such as sucrose (present in table sugar), which they can digest.

Secondary Lactase Deficiency: The most common cause of temporary lactose intolerance in infants and young children is by an infection that affects the gastrointestinal tract and can damage the lining of the small intestine.

Rotavirus and Giardia are two common organisms that cause damage to the surface of the small intestine resulting in temporary lactose intolerance. Older infants and young children will commonly be infected by a rotavirus. The symptoms of rotavirus infection include vomiting, diarrhea (frequent watery stools), and fever. Giardia is a parasite that is found in well water and fresh water from lakes and streams. Treatment of giardia infection with antibiotics will resolve the lactose intolerance.

Secondary lactase deficiency can also be due to Celiac disease, which is an intolerance or allergy to gluten, the protein found in wheat, rye, barley, and other grains. Crohn’s disease is an inflammatory condition that can affect any part of the gastrointestinal tract can lead to secondary lactase deficiency as well. Once each of these conditions is treated, the lactase deficiency will typically resolve. The lactose intolerance usually resolves within three to four weeks when the lining of the intestines returns to normal.

Acquired Lactase Deficiency: Many individuals acquire lactose intolerance as they get older. It is estimated that approximately one half of adults in the United States have acquired lactase deficiency. This condition is due to a normal decline in the amount of the enzyme lactase present in the small intestine as we age. Although lactose is an important part of the diet in infants and young children it represents only 10% of the carbohydrate (sugar) intake in adults. However, individuals who are lactose intolerant may not be able to tolerate even small amounts of this sugar in their diet.

Lactose intolerance occurs more frequently in certain families. One of the most important factors affecting the rate of developing lactose intolerance is an individual’s ethnic background. Approximately 15% of adult Caucasians, and 85% of adult African Americans in the United States are lactose intolerant. The rate of lactose intolerance is also very high in individuals of Asian descent, Hispanic descent, Native Americans and Jewish individuals.


Lactose intolerance is diagnosed by a simple test called a hydrogen breath test. After a overnight fast before the test, an individual breathes into a bag and then drinks a specified amount of the milk sugar as a syrup. In adults this corresponds to the amount of milk sugar in a quart of milk.  Subsequent breath samples are taken for up to three hours. The breath that they exhale into the bag is analyzed to determine its hydrogen content. During the test individuals who are lactose intolerant will have an increase in the amount of hydrogen that they exhale. If the values for hydrogen increase above a certain value, the diagnosis of lactose intolerance is made. Patients who are lactose intolerant may also develop their typical symptoms during the test.     

In those who cannot undergo testing, removal of lactose from the diet and possible supplementation with lactase can be done for 2 weeks to see if this improves the symptoms and see if symptoms return if lactose is added back to the diet. .


The best treatment of lactose intolerance is a combination of dietary modification to avoid lactose containing foods, and if eating foods with lactose taking a supplement to aid in digestion of lactose. Individuals who are lactose intolerant should meet with a dietician to review the sources of lactose in their diet. Some reduction in the daily lactose consumption is usually required. When an individual is going to be eating a food that contains lactose they should take a commercially available non-prescription lactase supplement at the time of lactose ingestion. This type of supplement can be taken throughout the day whenever lactose is ingested. Some individuals will be less lactose intolerant and therefore will be able to tolerate comparatively larger amounts of lactose. Alternatives to milk for lactose intolerant individuals include products such as soy milk. If an individual is restricting their milk/ dairy intake it is important to ensure adequate supplementation of calcium and Vitamin D in the diet. This is especially important for pediatric patients and women.

Recommended daily calcium intakes:
1-3 years of age500 mg
4-8 years of age800 mg
9-24 years of age1300 mg
Age 25 and above800-1000 mg
Pregnant and nursing women1200 mg

Author(s) and Publication Date(s)

Ryan K. Fawley, MD, Naval Medical Center San Diego, CA – Updated October 2021.

Marsha H. Kay, MD, The Cleveland Clinic, Cleveland, OH, and Anthony F. Porto, MD, MPH, Yale University/Greenwich Hospital, Greenwich, CT – Updated December 2012.

Marsha H. Kay, MD, The Cleveland Clinic, Cleveland, OH, and Vasundhara Tolia, MD, Children’s Hospital of Michigan, Detroit, MI – Published September 2004.

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Lactose Intolerance – American Family Physician

1. Lloyd ML, Olsen WA. Disaccharide malabsorption. In: Haubrich WS, Schaffner F, Berk JE, eds., Bockus HL. Bockus Gastroenterology. 5th ed. Philadelphia: Saunders, 1995:1087–1100….

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Allaying fears and fallacies about lactose intolerance. J Am Diet Assoc.

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When to suspect lactose intolerance. Symptomatic, ethnic, and laboratory clues. Postgrad Med.

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Lactose intolerance: problems in diagnosis and treatment. J Clin Gastroenterol.

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A randomized trial of Lacto-bacillus acidophilus BG2FO4 to treat lactose intolerance. Am J Clin Nutr.

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Diagnosis of hypolactasia and lactose malabsorption. Scand J Gastroenterol.

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5 Can’t-Miss Signs That Your Child Is Lactose Intolerant – Cleveland Clinic

By pediatric gastroenterologist Kadakkal Radhakrishnan, MD

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an ice cream treat or a glass of milk leaves your child complaining of an upset
stomach, you might wonder if lactose intolerance is to blame.

who are lactose intolerant don’t produce enough lactase, a natural enzyme in
the digestive tract that breaks down lactose. In order to pinpoint if your
child has this issue, it’s important to be aware of the signs and symptoms.

How lactose intolerance works

is a sugar found in foods that many children love, including milk, ice cream
and soft cheeses. It’s also present in some baked goods, salad dressings,
sauces, candy and other foods you might not expect. Breast milk and infant
formulas contain lactose, too.

is made up of two simple sugar molecules — glucose and galactose. In order for
it to be absorbed by the body, lactose has to be split into its two components
by an enzyme called lactase, which is found in the lining of the
small intestine.

But for those who are lactose intolerant, the activity of lactase is ineffective, and it’s unable to digest and absorb lactose in the small intestine. The lactose then passes into the large intestine, where it is fermented by gut bacteria. This process produces carbon dioxide and hydrogen, as well as certain byproducts that have a laxative effect.

Signs your child is lactose intolerant

your child is intolerant, the more lactose he or she consumes, the more
symptoms he or she will experience.

Here are some symptoms you should watch out for, especially after your child eats dairy products:

  • Loose stools and gas, especially when your child eats dairy products.
  • Watery diarrhea with gas.
  • Stomach bloating, gas and nausea.
  • Skin rash and frequent colds.
  • Generalized abdominal pain and cramping.

Parents sometimes confuse lactose intolerance with milk allergy. Although the two have similar symptoms, they are very different conditions. A milk allergy is a serious immune system reaction that usually appears in the first year of life. Lactose intolerance is a digestive issue that is rarely seen in infants or toddlers.

Lactose intolerance symptoms can start in late childhood or adolescence, and can become more noticeable into adulthood.

Aside from the discomfort associated with these symptoms, lactose intolerance is a nonthreatening disorder with no long-term complications. Symptoms can be avoided by limiting certain foods in your child’s diet.

How lactose intolerance develops

intolerance can develop in three different ways:

Acquired lactose intolerance

Lactase activity in the small intestine naturally declines after infancy. The National Institutes of Health estimates that as many as two-thirds of people aren’t able to fully digest lactose beyond childhood.

Primary lactase deficiency

Rarely, babies are born with a complete absence of the lactase enzyme. These babies develop severe diarrhea while on breast milk, forcing them to require special formulas. This is a recessive trait, so the baby must acquire one abnormal gene from each parent to have the symptoms.

Secondary lactose intolerance

Someone can develop a temporary intolerance after an infection that causes irritation of the digestive tract, such as rotavirus or giardiasis. Patients often first have nausea, vomiting and diarrhea, then continue to have diarrhea when consuming lactose-containing foods for some time after the infection has cleared.

Celiac disease, a digestive disorder that causes damage to the small intestine when gluten is ingested, can also be associated with temporary lactose intolerance. Those with celiac disease can tolerate lactose-containing foods once the intestinal lining heals after going on a strict gluten-free diet. Crohn’s disease, an inflammatory disorder of the bowel, also can be associated with lactose intolerance. This often improves once adequate treatment is in place.

Diagnosis and dietary changes

quite easy to test for lactose intolerance. It’s done using a lactose breath
test, which measures hydrogen levels in the breath after consuming lactose.

very little hydrogen is detected in breath. Raised hydrogen breath levels
indicate the improper digestion of lactose, which could indicate lactose
intolerance. In young children and those who cannot perform the breath
test, strict elimination of lactose-containing food for two to four weeks is
another option.

there is no cure for this digestive problem, some dietary changes can make a
huge difference for your child. I also recommend children with lactose
intolerance take an over-the-counter lactase enzyme supplement if they are
going to eat any lactose-containing foods to help alleviate symptoms. However,
this may not help if consumed with large amounts of lactose-containing foods.

time, you and your child will learn how much dairy-based food and drink he or
she can handle. For patients with significant symptoms, a dietitian can help
identify foods containing lactose.

It is also important to make sure your child still gets enough calcium and vitamin D, since dairy is normally a good source for these nutrients.

Lactose Intolerance | Michigan Medicine

Topic Overview

What is lactose intolerance?

Lactose intolerance means the body cannot easily digest lactose, a type of natural sugar found in milk and dairy products. This is not the same thing as a food allergy to milk.

When lactose moves through the large intestine (colon) without being properly digested, it can cause uncomfortable symptoms such as gas, belly pain, and bloating. Some people who have lactose intolerance cannot digest any milk products. Others can eat or drink small amounts of milk products or certain types of milk products without problems.

Lactose intolerance is common in adults. It occurs more often in Native Americans and people of Asian, African, and South American descent than among people of European descent.

A big challenge for people who are lactose-intolerant is learning how to eat to avoid discomfort and to get enough calcium for healthy bones.

What causes lactose intolerance?

Lactose intolerance occurs when the small intestine does not make enough of an enzyme called lactase. Your body needs lactase to break down, or digest, lactose.

Lactose intolerance most commonly runs in families, and symptoms usually develop during the teen or adult years. Most people with this type of lactose intolerance can eat some milk or dairy products without problems.

Sometimes the small intestine stops making lactase after a short-term illness such as the stomach flu or as part of a lifelong disease such as cystic fibrosis. Or the small intestine sometimes stops making lactase after surgery to remove a part of the small intestine. In these cases, the problem can be either permanent or temporary.

In rare cases, newborns are lactose-intolerant. A person born with lactose intolerance cannot eat or drink anything with lactose.

Some premature babies have temporary lactose intolerance because they are not yet able to make lactase. After a baby begins to make lactase, the condition typically goes away.

What are the symptoms?

Symptoms of lactose intolerance can be mild to severe, depending on how much lactase your body makes. Symptoms usually begin 30 minutes to 2 hours after you eat or drink milk products. If you have lactose intolerance, your symptoms may include:

  • Bloating.
  • Pain or cramps.
  • Gurgling or rumbling sounds in your belly.
  • Gas.
  • Loose stools or diarrhea.
  • Throwing up.

Many people who have gas, belly pain, bloating, and diarrhea suspect they may be lactose-intolerant. The best way to check this is to avoid eating all milk and dairy products to see if your symptoms go away. If they do, then you can try adding small amounts of milk products to see if your symptoms come back.

If you feel sick after drinking a glass of milk one time, you probably do not have lactose intolerance. But if you feel sick every time you have milk, ice cream, or another dairy product, you may have lactose intolerance.

Sometimes people who have never had problems with milk or dairy products suddenly have lactose intolerance. This is more common as you get older.

If you think you might have lactose intolerance, talk with your doctor. He or she can make sure that your symptoms are caused by lactose intolerance and not by another problem.

How is lactose intolerance diagnosed?

A doctor can usually tell whether you have lactose intolerance by asking questions about your symptoms. He or she may also ask that you avoid dairy products for a short time to see if your symptoms improve.

Sometimes doctors order a hydrogen breath test or a blood sugar test to confirm the diagnosis. These simple tests check to see if you are digesting lactose normally.

How is it treated?

There is no cure for lactose intolerance. But you can treat your symptoms by limiting or avoiding milk products. Some people use milk with reduced lactose, or they substitute soy milk and soy cheese for milk and milk products. Some people who are lactose-intolerant can eat yogurt without problems, especially yogurt with live cultures. You can also take dietary supplements called lactase products that help digest lactose. In time, most people who have lactose intolerance get to know their bodies well enough to avoid symptoms.

One of the biggest concerns for people who are lactose-intolerant is making sure they get enough of the nutrients found in milk products, especially calcium. Calcium is most important for children, teens, pregnant women, and women after menopause. There are many nondairy foods that contain calcium, including:

  • Broccoli, okra, kale, collards, and turnip greens.
  • Canned sardines, tuna, and salmon.
  • Calcium-fortified juices and cereals.
  • Calcium-fortified soy products such as soy milk, tofu, and soybeans.
  • Almonds.


Symptoms of lactose intolerance can be mild or severe, depending on how much lactase your body makes. Symptoms usually begin 30 minutes to 2 hours after eating or drinking milk or milk products. If you have lactose intolerance, your symptoms may include:

  • Bloating.
  • Pain or cramps in the lower belly.
  • Gurgling or rumbling sounds in the lower belly.
  • Gas.
  • Loose stools or diarrhea. Sometimes the stools are foamy.
  • Throwing up.

Many people think they are lactose-intolerant, because the symptoms of lactose intolerance are very common symptoms. If you feel sick after drinking a glass of milk one time, you probably do not have lactose intolerance. But if you feel sick every time you have milk, ice cream, or another dairy product, you may have lactose intolerance.

Sometimes people who have never had problems with milk or dairy products suddenly have lactose intolerance. This is more common as you get older.

Symptoms of the most common type of lactose intolerance—adult lactose intolerance—often start during the teen or adult years and continue for life. Symptoms of acquired lactose intolerance last as long as the small intestine does not make lactase.

In rare cases, newborns are lactose-intolerant. Symptoms in newborns include severe foamy diarrhea, diaper rash, vomiting, dehydration, weakness and irritability, and slow weight gain.

Lactose intolerance is not the same thing as a food allergy to milk. Symptoms of a milk allergy are usually more severe than those from lactose intolerance. People who have a milk allergy cannot eat or drink any milk products. For more information, see the topic Food Allergies.

If you think you might have lactose intolerance, talk it over with your doctor. Your doctor can make sure that your symptoms are caused by lactose intolerance and not by another problem. Other conditions can cause symptoms similar to those of lactose intolerance, including irritable bowel syndrome, inflammatory bowel disease, overuse of laxatives, and problems digesting foods that contain fructose and sorbitol.

Exams and Tests

If your doctor thinks you have lactose intolerance, he or she will ask questions about your medical history and do a physical exam. Before making a diagnosis, your doctor may ask that you avoid dairy products for a short time to see if your symptoms improve. You may also be asked to bring in a sample of your stool. The stool of a person who has lactose intolerance is usually loose or watery. It also can be foamy.

To confirm a diagnosis, your doctor may order a:

  • Hydrogen breath test. This is the most accurate lactose intolerance test. Before the test, you need to avoid certain foods and medicines and cigarettes. On the day of the test, you will drink a liquid that contains lactose and then breathe into a machine several times over a couple of hours. If the hydrogen levels in your breath are high, you may have lactose intolerance. This test is not usually done on babies and very young children, because it can cause severe diarrhea.
  • Lactose tolerance test. This test measures your blood sugar after you eat or drink lactose. After midnight on the night before the test, you should not eat or drink anything. On the day of your test, you will drink a liquid that contains lactose, which may cause gas or pain in your belly. Then your blood will be tested every 30 minutes for 2 hours. If your blood sugar levels do not rise, you may be lactose-intolerant. This test is not done on people who have diabetes. And it is usually not done on babies and very young children.

Treatment Overview

If you think you have lactose intolerance, it is a good idea to talk it over with your doctor. Your doctor can make sure that your symptoms are caused by lactose intolerance and not by another problem such as irritable bowel syndrome, inflammatory bowel disease, overuse of laxatives, or problems digesting foods that contain fructose or sorbitol. Your doctor can also make sure that your lactose intolerance is not related to another health problem.

After being diagnosed with lactose intolerance, you may feel relieved to find out what has been causing your symptoms. You may also feel frustrated by having to deal with this condition for the rest of your life. You may find it reassuring to know that there are many people who have lactose intolerance. Most can avoid discomfort and still eat or drink some milk products throughout the day.

There are different ways to live with lactose intolerance. What works for one person may not work for another. Because there is no cure for lactose intolerance, controlling your symptoms is mostly up to you. The following tips can help you prevent symptoms of lactose intolerance.

Limit the amount of milk and milk products in your diet. Most people can have about 10 g of lactose each day. This can be a glass of whole, low-fat, or fat-free milk, for example. All milk contains the same amount of lactose. Other milk products contain different amounts of lactose:

Approximate lactose and calcium in some foods footnote 1


Serving size

Lactose (g)

Calcium (mg)

Milk, fat-free

8 fl oz (240 mL)

12. 5


Cheddar cheese

1 oz (30 g)



Cottage cheese, 2% milk fat

4 oz (113 g)



Cream cheese

1 oz (30 g)



Foods with less lactose, such as Swiss or cheddar cheese, may not cause problems. If you are not sure whether a milk product causes symptoms, try a small amount and wait to see how you feel before you eat or drink more.

Eat or drink milk and milk products along with other foods. For some people, combining a solid food (like cereal) with a dairy product (like milk) may reduce or eliminate symptoms.

Spread milk or milk products throughout the day. Many people who are lactose-intolerant find it helpful to eat small amounts of lactose-containing products throughout the day instead of larger amounts all at one time.

Eat or drink milk and milk products that have reduced lactose. In most grocery stores, you can buy milk with reduced lactose. Some people like buying this kind of milk and find that it helps control their symptoms. Others find that it tastes too sweet or is too expensive. People who have diabetes may find that lactose-reduced milk raises their blood sugar levels higher than normal.

Eat or drink other foods instead of milk and milk products. You can substitute soy milk and soy cheese for milk and milk products. You can also use nondairy creamers in your coffee. But keep in mind that nondairy creamers do not contain the same vitamins and minerals as milk, and they may contain more fat than milk contains.

Use lactase products. Lactase products are dietary supplements that help you digest lactose. There are many different brands of lactase products. Some are pills that you chew (such as Lactaid) before you eat or drink milk products. Others are liquids that you can add to milk 24 hours before you drink it. Some foods have extra lactase added to them. Because products and brands are different, you may want to try a few to see which ones work best for you.

Eat yogurt with live and active cultures. Some people who are lactose-intolerant can eat yogurt without having problems, especially yogurt that contains live and active cultures. This type of yogurt can help people digest lactose. All yogurts are made with live cultures, but many yogurts go through a process called “heat treatment” that kills the bacteria. Check the label for the words “contains live and active cultures.” It’s best to try a small amount of different brands of yogurt to see which ones work best for you.

If you have severe lactose intolerance, you may need to avoid lactose completely. Some medicines and many prepared foods contain lactose. Examples of prepared foods with lactose include breads and baked goods; breakfast cereals and instant breakfast drinks; instant potatoes and instant soups; pancake, cookie, and biscuit mixes; margarine and salad dressings; candies, milk chocolate, and other snacks. Be sure to read labels for lactose and for lactose’s “hidden” names, such as:

  • Dry milk solids.
  • Whey.
  • Curds.
  • Milk by-products.
  • Nonfat dry milk powder.

One of the biggest concerns for people who are lactose-intolerant is making sure they get enough of the nutrients found in milk products, especially calcium. Calcium is especially important for women, because it keeps bones strong and reduces the risk of osteoporosis. There are many nondairy foods that contain calcium, including:

  • Broccoli, okra, kale, collards, and turnip greens.
  • Canned sardines, tuna, and salmon.
  • Calcium-fortified juices and cereals.
  • Calcium-fortified soy products such as soy milk, tofu, and soybeans.
  • Almonds.

To absorb calcium, your body needs vitamin D. Most people get enough vitamin D by being out in the sun for short periods of time each day. Vitamin D is also found in fortified orange juice, fortified soy milk, oily fish (such as salmon), egg yolks, and liver.

If you don’t know whether you are getting enough calcium, vitamin D, and other important nutrients found in milk products, such as magnesium, potassium, protein, and riboflavin, talk to your doctor. He or she may recommend that you take a calcium supplement or meet with a registered dietitian to make sure you are getting enough of certain vitamins and minerals.

You should also talk with your doctor if your symptoms do not go away with treatment, if they get worse, or if you have other symptoms, such as a fever, chills, or severe belly pain or vomiting.

What to think about

Lactose intolerance in newborns of normal birth weight and in babies is rare. But if your child has symptoms of lactose intolerance, see your doctor right away. Diarrhea is very dangerous because it can lead to dehydration, a serious problem that requires immediate attention.

Babies who are only fed breast milk do not develop lactose intolerance, because breast milk contains lactase, the enzyme that helps digest milk sugar. If your baby is formula-fed and develops lactose intolerance, you can switch to a formula made without lactose. In rare cases, a baby may have a reaction to the proteins in milk, which is a different condition called sensitivity to milk protein.



  1. U.S. Department of Agriculture, Agricultural Research Service (2012). Nutrient data laboratory. USDA National Nutrient Database for Standard Reference, Release 25. Available online: http://ndb.nal.usda.gov.

Other Works Consulted

  • American Academy of Pediatrics (2014). Carbohydrate and dietary fiber. In Pediatric Nutrition, 7th ed., pp. 387–406. Elk Grove Village, IL: American Academy of Pediatrics.
  • Hogenauer C, Hammer HF (2010). Maldigestion and malabsorption. In M Feldman et al., eds., Sleisenger and Fordtran’s Gastrointestinal and Liver Disease, 9th ed. , vol. 2, pp. 1735–1767. Philadelphia: Saunders.
  • Whitney E, Rolfes SR (2011). Digestion and absorption of carbohydrates section of The carbohydrates: Sugars, starches, and fibers. In Understanding Nutrition, 12th ed., pp. 105–107. Belmont, CA: Wadsworth.


Current as of:
November 6, 2020

Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD – Internal Medicine
Adam Husney MD – Family Medicine
John Pope MD – Pediatrics
Martin J. Gabica MD – Family Medicine
Kathleen Romito MD – Family Medicine
Rohit K Katial MD – Allergy and Immunology

29.13C: Lactose Intolerance – Medicine LibreTexts

Lactose intolerance is the inability to digest lactose, a sugar found in milk, due to a lack of the enzyme lactase.

Learning Objectives

  • Analyze lactose intolerance and tolerance

Key Points

  • Symptoms of lactose intolerance include abdominal bloating and cramps, flatulence, diarrhea, nausea, borborygmi (rumbling stomach), and/or vomiting after consuming significant amounts of lactose. Individuals may be lactose intolerant to varying degrees, depending on the severity of these symptoms.
  • Most mammals normally become lactose intolerant after weaning, but some human populations have developed lactase persistence, in which lactase production continues into adulthood. These populations (northern Europe, India, and a few groups in Africa) are dairying cultures.
  • Lactase deficiency has a number of causes, and is therefore classified as one of three types: primary, secondary, or congenital. Primary lactase deficiency is genetic and normal as most adults worldwide do not maintain lactase production.
  • Secondary/acquired/transient lactase deficiency is caused by an injury to the small intestine. Congenital lactase deficiency prevents lactase expression from birth, making nourishment from breast milk impossible.
  • Lactose intolerance is not an allergy, because it is not an immune response, but rather a problem with digestion caused by lactase deficiency. Milk allergy is a separate condition, with distinct symptoms that occur when the presence of milk proteins trigger an immune reaction.
  • Primary lactase deficiency is genetic, secondary/acquired/transient lactase deficiency is caused by an injury to the small intestine, and congenital lactase deficiency prevents lactase expression from birth.

Key Terms

  • lactose: The disaccharide sugar of milk and dairy products, C12h32O11, (a product of glucose and galactose) used as a food and in medicinal compounds.
  • lactose intolerance: The inability to fully metabolize lactose.
  • lactase: A β-galactosidase enzyme that is involved in the hydrolysis of the disaccharide lactose into constituent galactose and glucose monomers.


Those who are lactose intolerant can be more tolerant of traditionally made yogurt than of milk because it contains lactase produced by the bacterial cultures used to make the yogurt. Frozen yogurt, if cultured similarly to its unfrozen counterpart, will contain similarly reduced lactose levels. However, many commercial brands contain milk solids, increasing the lactose content.

Lactose intolerance, also called lactase deficiency and hypolactasia, is the inability to digest lactose, a sugar found in milk and, to a lesser extent, in milk-derived dairy products. Lactose intolerant individuals have insufficient levels of lactase, the enzyme that metabolizes lactose into glucose and galactose, in their digestive system. In most cases, this causes symptoms such as abdominal bloating and cramps, flatulence, diarrhea, nausea, borborygmi (rumbling stomach), and/or vomiting after consuming significant amounts of lactose. Some studies in the U.S. and elsewhere suggest that milk consumption by lactose intolerant individuals may be a significant cause of irritable bowel syndrome.

Lactose: Lactose, a disaccharide of β-D-galactose and β-D-glucose, is normally broken down by the enzyme lactase into its component monosaccharides. Individuals who suffer from lactose intolerance have insufficient levels of lactase to break down the lactose in milk and dairy products.

Most mammals normally become lactose intolerant after weaning, but some human populations have developed lactase persistence, in which lactase production continues into adulthood. It is estimated that 75% of adults worldwide show some decrease in lactase activity during adulthood. The frequency of decreased lactase activity ranges from 5% in northern Europe through 71% for Sicily to more than 90% in some African and Asian countries. This distribution is now thought to have been caused by recent natural selection favoring lactase persistent individuals in cultures that rely on dairy products. While it was first thought that this would mean that populations in Europe, India, and Africa that had high frequencies of lactase persistence shared a single mutation, it has now been shown that lactase persistence is caused by several independently occurring mutations.


Primary lactase deficiency is genetic, only affects adults, and is caused by the absence of a lactase persistence allele. It is the most common cause of lactose intolerance as a majority of the world’s population lacks these alleles. Secondary, acquired, or transient lactase deficiency is caused by an injury to the small intestine, usually during infancy, from acute gastroenteritis, diarrhea, chemotherapy, intestinal parasites, or other environmental causes. Congenital lactase deficiency is a very rare, autosomal recessive genetic disorder that prevents lactase expression from birth. It is particularly common in Finland. People with congenital lactase deficiency who are unable to digest lactose from birth are unable to digest breast milk.

Effects on Nutrition

While dairy products can be a significant source of nutrients in some societies, there is no evidence that lactose intolerance has any adverse impact on nutrition where consumption is the norm among adults. Congenital lactase deficiency (CLD), where the production of lactase is inhibited from birth, can be dangerous in any society because of infants’ nutritional reliance on breast milk during their first months. Before the 20th century, babies born with CLD were not expected to survive, but these death rates can now be lowered using soybean-derived infant formulas and manufactured lactose-free dairy products. Beyond infancy, individuals affected by CLD usually have the same nutritional concerns as any lactose-intolerant adult.

Lactose cannot be directly absorbed through the wall of the small intestine into the bloodstream so, in the absence of lactase, it passes intact into the colon. Bacteria in the colon are able to metabolize lactose and the resulting fermentation produces copious amounts of gas (a mixture of hydrogen, carbon dioxide, and methane) that causes the various abdominal symptoms. The unabsorbed sugars and fermentation products also raise the osmotic pressure of the colon, resulting in an increased flow of water into the bowels (diarrhea).

Assessment and Treatment of Lactose Intolerance

To assess lactose intolerance, intestinal function is challenged by ingesting more dairy products than can be readily digested. Clinical symptoms typically appear within 30 minutes, but may take up to two hours, depending on other foods and activities. Substantial variability in response (symptoms of nausea, cramping, bloating, diarrhea, and flatulence) is to be expected, as the extent and severity of lactose intolerance varies among individuals.

It is important to distinguish lactose intolerance from milk allergy, an abnormal immune response (usually) to milk proteins. This may be done in diagnosis by giving lactose-free milk, producing no symptoms in the case of lactose intolerance, but the same reaction as to normal milk if it is a milk allergy. An intermediate result might suggest that the person has both conditions. Since lactose intolerance is the normal state for most adults worldwide, it is not considered a disease and a medical diagnosis is not normally required, although tests are available if confirmation is necessary.

Lactose intolerance is not considered a condition that requires treatment in societies where the diet contains relatively little dairy. However, those living among societies that are largely lactose-tolerant may find lactose intolerance troublesome. Although there are still no methodologies to reinstate lactase production, some individuals have reported that their intolerance varies over time, depending on health status and pregnancy. About 44% of lactose intolerant women regain the ability to digest lactose during pregnancy. This might be caused by slow intestinal transit and intestinal flora changes during pregnancy.

Lactose Intolerance: Symptoms and Causes

Symptoms of lactose intolerance include bloating and diarrhoea.​ The Department of Dietetics at Singapore General Hospital (SGH) shares its causes and symptoms.

Lactose intolerance: the most common food intolerance in Asians

Lactose intolerance is due to the deficiency of an enzyme called lactase, normally found in the small intestine. When lactase is insufficient, the lactose (milk sugar) contained in dairy products cannot be fully digested.

When undigested lactose moves to the colon from the small intestine, it interacts with normal intestinal bacteria.​

What are the symptoms of lactose intolerance?

“Common symptoms of lactose intolerance include bloating, abdominal cramps, nausea and diarrhoea,” say​ doctors at the
Department of Gastroenterology and Hepatology at
Singapore General Hospital, a member of the ​SingHealth​ group.​ These symptoms usually begin about 30 minutes to two hours after consuming milk or dairy products including powdered milk, ice cream and evaporated milk.

Symptoms usually disappear when foods with high levels of lactose are removed from one’s diet.

Is lactose intolerance acquired?

Lactose intolerance can be caused by genetic factors or it can also develop due to age, bowel injury or gastrointestinal disorders.

If the small intestine produces less lactase after an illness, surgery or injury to the small intestine, the lactose intolerance can last from a few days to a couple of weeks, and may be reversible. In children in particular, such a temporary lactase deficiency can also result from a viral or bacterial infection.

In rare cases where​ babies are born ‘lactose intolerant’ due to a complete absence of lactase activity, these babies require lactose-free formula as they are intolerant to lactose found in their mothers’ breast milk.

See next page to learn
how lactose ​intolerance is diagnosed and ways to cope with it​.

Ref: O17​​​

Kids Health Information : Lactose intolerance

Lactose is a type of sugar found in milk and milk products. Lactose intolerance happens when a person eats or drinks more lactose than their body can digest. It is not caused by an allergy to milk. The symptoms of lactose intolerance most commonly include stomach pain and diarrhoea.

Lactose intolerance occurs when the body doesn’t have enough of the enzyme (chemical) called lactase, which helps digest lactose. A temporary lactose intolerance can happen after some illnesses, such as gastroenteritis, when the body’s stores of lactase are temporarily reduced. Inflammation of the
bowel as a result of intolerance to other foods, infection or bowel surgery can also result in lactose intolerance.

For children aged seven to 10 years, lactose intolerance is usually treated by avoiding products containing milk or lactose. Some children develop a permanent intolerance to lactose and have to avoid milk products for the rest of their lives.

Signs and symptoms of lactose intolerance

If your child has lactose intolerance, after consuming milk or milk products they are likely to have: 

  • stomach pain or bloating
  • diarrhoea

  • wind.

Lactose intolerance is very rare in babies. However, if your baby displays unsettled behaviour, poor growth, loose bowel actions and significant nappy rash, this may indicate a lactose intolerance. 

When to see a doctor

If your child has symptoms of lactose intolerance, take them to see a GP. The doctor will be able to determine if your child is lactose intolerant and rule out other conditions. They may do some investigations and recommend that you see a dietician. It is important not to self-diagnose your
child and make changes to their diet without consulting a doctor or dietitian.

A low lactose diet

If your child is found to be lactose intolerant, a low lactose diet will be recommended for a few weeks. This means reducing their intake of products that have milk or lactose in them. These include products containing:

  • milk
  • skim milk powder
  • non-fat milk solids
  • yoghurt
  • milk protein
  • milk solids.

Read ingredient labels on commercial products carefully. Check with your doctor or pharmacist whether any medication your child is prescribed contains lactose.

If your child does consume some lactose there is no need for concern – children with lactose intolerance will usually be able to tolerate small amounts of lactose; however, large amounts of lactose often produce symptoms.

Low lactose diets for children

Select appropriate foods from each of the following groups each day for a nutritious, low lactose diet.

Milk and milk products

  • Avoid milk, yoghurt, cream, ice-cream or milk desserts containing lactose. Also avoid cream cheese, processed cheese, cheese spread, cottage cheese and ricotta cheese.
  • All other cheeses, including hard cheeses such as cheddar and parmesan, contain a low amount of lactose and are usually well tolerated.
  • Milk is a very important source of calcium, protein and vitamins in a child’s diet. There are a number of low lactose milks available in the long-life section or dairy cabinet in most supermarkets. Calcium-fortified soy milk is also lactose-free.
  • Use lactose-free milk in place of regular milk for cereals, custards and sauces.
  • Low lactose yoghurt, cream and sour cream are now available.
  • Low lactose and soy-based yoghurts are also available in most large supermarkets, and come in a variety of flavours.

For young children, aim for two to three serves of low lactose dairy products or lactose-free milk each day. For older children, aim for three serves of low lactose dairy products or lactose-free milk each day. Teenagers should aim for four serves of low lactose dairy products or
lactose-free milk each day.

Breads, cereals, rice and pasta

  • These provide energy, B vitamins and fibre. Check labels on breakfast cereal packets and avoid those containing milk or lactose.

Fruit and vegetables (fresh, frozen, tinned or dried)

  • These provide energy, vitamins, minerals and fibre. Avoid instant mashed potato and vegetables with added milk, white or cheese sauces.

Meat and protein foods (including fish, chicken, pulses and legumes)

  • These provide protein and minerals and are safe for children on low lactose diets. 

Fats and oils

  • Butter, margarine and oil provide energy and some vitamins. They are low in lactose and are usually tolerated in small amounts.

Other foods

  • Other foods that may contain lactose include milk chocolate, chocolate-coated biscuits, creamed soups and cakes.

Lacteeze drops and tablets contain lactase, which breaks down lactose. The drops can be added to foods containing lactose, making the food lactose-free, while the tablets can be taken before eating foods with lactose in them as the lactase will help with the digestion of lactose. You can buy
Lacteeze online or from pharmacies.

Low lactose diets for infants

If your baby is diagnosed with lactose intolerance, an infant formula product that is low in lactose may be recommended. Soy formula is not recommended for infants younger than six months old.

If you are breastfeeding your baby, even if you reduce lactose in your own diet, lactose will still be present in your breastmilk. You can speak to a lactation consultant about adjusting breastfeeding to reduce the amount of lactose passed through to your baby. Your doctor may recommend giving
your baby Lacteeze during feeding – discuss how this can be done with your doctor. 


After the low lactose diet, a normal diet containing lactose can usually be reintroduced in consultation with your child’s doctor or dietitian.  This needs to be done slowly and under supervision, over the course of a week or longer.

Key points to remember

  • Only change to a low lactose or lactose free diet in consultation with your child’s doctor or dietitian.
  • Read ingredient labels on food products carefully to avoid ingredients that contain large amounts of milk or lactose.
  • Check with your doctor or pharmacist whether any medications your child is using contain lactose.
  • Small amounts of lactose are usually well tolerated. Large amounts of lactose usually produce symptoms.
  • Discuss with your child’s doctor or dietitian the reintroduction of foods containing lactose.

For more information

Common questions our doctors are asked

What’s the difference between lactose intolerance and milk

Lactose intolerance and allergy to milk are different
conditions, though they may share similar symptoms which occur after your child
has had milk or dairy products. Lactose intolerance is a problem with the
digestive system, while a milk allergy is a problem with the immune system.
Lactose intolerance may cause pain and discomfort but is not dangerous, whereas
an allergy can cause the life-threatening reaction anaphylaxis. 

If my baby is lactose intolerant and I am breastfeeding, do
I need to cut dairy out of my diet?

Reducing the amount of dairy a mother ingests will reduce
the amount of cow-milk protein that gets passed through to a breast-fed child.
This can be helpful for a different condition, called cow-milk protein
intolerance. Even when a breast-feeding mother excludes dairy completely from
her own diet, lactose is still found in breastmilk. Remember, true lactose
intolerance is very rare in babies.

How is lactose intolerance diagnosed?

Lactose intolerance
can be investigated by assessing a sample of your child’s stool (poo) or via a
breath-test. Discuss these different tests with your child’s doctor.

Developed by The Royal Children’s Hospital Gastroenterology and Nutrition and Food Services departments. We acknowledge the input of RCH consumers and carers.

Reviewed May 2018.

Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit

Lactase deficiency in adults

Lactase deficiency is a violation of the breakdown of lactose due to a deficiency of the enzyme lactase of the mucous membrane of the small intestine, accompanied by clinical symptoms.

Lactose is milk sugar. The enzyme that breaks down lactose is called lactase.

Adult-type lactase deficiency develops after a period of breastfeeding. This is due to the gradual decrease in lactase activity with age.After ingestion of dairy products or whole milk, as a rule, intestinal disorders (diarrhea, flatulence) appear. Prevention and treatment consists of adhering to a diet low in lactose or completely eliminating it.

Russian synonyms

Congenital lactase deficiency in adults (type with delayed onset), primary lactase deficiency of the adult type, hypolactasia, lactose intolerance, lactose malabsorption.

English synonyms

#OMIM 223100, Lactose intolerance, adult type, Hypolactasia, adult type, Disaccharide intolerance III.


Lactase deficiency is characterized by the development of intestinal symptoms after ingestion of milk and dairy products: flatulence, pain and rumbling in the abdomen, diarrhea, bloating. Nausea is possible. The stool is liquid or mushy, light yellow in color, with a sour odor.

General information about the disease

Lactase deficiency, or primary lactase deficiency, is a violation of the breakdown of lactose due to a deficiency of the lactase enzyme of the mucous membrane of the small intestine, accompanied by clinical symptoms. It is caused by a genetically determined decrease in its production, which manifests itself in the inability to absorb milk sugar (lactose).

The activity of lactase is manifested from the 12-14th week of intrauterine development and reaches its maximum values ​​by the time of birth (at a period of 39-40 weeks). After birth, lactase is produced in large quantities, but by the end of the first year of life, its production decreases. This is the primary, or congenital, late-onset lactase deficiency, which is inherited in an autosomal recessive manner.

Nonspecific abdominal symptoms (bloating, upset stools, nausea) develop after eating foods containing lactose, mainly whole milk and dairy products. But today lactose is added to other food products (for example, meat, confectionery). The pharmaceutical industry also uses it as an excipient.

The severity of symptoms of hypolactasia depends on the individual physiological characteristics of a person, intestinal microflora, diet, psychological factors. Deliberate avoidance of milk, which is an important source of calcium, can lead to a deficiency of this element and, as a result, to osteoporosis. Keep this in mind and cover your daily requirement with other calcium-rich foods. This is especially important for postmenopausal women.

Primary lactase deficiency should be distinguished from secondary (acquired), which occurs when the mucous membrane of the small intestine is damaged against the background of any acute or chronic disease.Such damage is possible with infectious (intestinal infection), immune (intolerance to cow’s milk protein), inflammatory processes in the intestines, atrophic changes (with celiac disease, after a long period of complete parenteral nutrition, etc.).

Also, this disorder should not be confused with congenital lactase deficiency, a rare genetic disorder, the symptoms of which appear immediately after birth and are associated with the initiation of breastfeeding.

There is a genetic diagnosis of late-onset primary lactase deficiency. The region of the MCM6 gene is one of the important regulatory elements of the lactase gene. The genetic marker MCM6 (C (-13910) T) is associated with lactose intolerance.

Who is at risk?

  • Persons with relatives with intolerance to milk and dairy products.
  • Identified ethnic groups. Lactose intolerance is most common in North America, Africa, Southeast Asia (the incidence of lactase deficiency is 70-100%). In the Russian population, lactase deficiency is observed in about 16%.
  • The condition is rare in the first year of life, the development of lactose intolerance is associated with adulthood.


The diagnosis can be assumed on the basis of genealogical data, the results of scatology (an increase in starch, fiber, iodophilic microflora, a decrease in fecal pH less than 5.5), determination of carbohydrates in feces. The diagnosis uses a hydrogen breath test. The concentration of hydrogen in exhaled air is determined before and after loading with lactose. In patients with lactase deficiency, an increase in hydrogen content is recorded, which is associated with increased bacterial breakdown of lactose in the colon. That is, lactose, which is not completely absorbed in the small intestine, reaches the large intestine, where it is broken down by anaerobic microflora.

Molecular genetic research for susceptibility to lactase deficiency is important in diagnostics. The analysis will help in the differential diagnosis of the causes of lactose malabsorption and in the selection of an appropriate diet.

In case of severe clinical manifestations, refusal of milk, it is also important to determine the calcium content in blood serum and in urine.


Diet therapy: restriction of foods containing lactose.

Prescription of enzyme preparations that break down lactose is possible.

It is allowed to use fermented milk products with a reduced amount of lactose (yoghurts, curdled milk), cottage cheese, butter, hard cheeses, as well as lactose-free.

It is important to take into account the possible lack of calcium intake on a dairy-free diet, which is recommended to be compensated for with other foods rich in it, or with medications.

In young children, lactase deficiency is often combined with intolerance to cow’s milk proteins. In this case, special mixtures are prescribed based on a complete milk protein hydrolyzate.

According to indications – antidiarrheal drugs, enzyme preparations, vitamin D preparations and other vitamin complexes, preparations for the restoration of intestinal biocenosis.


Prevention consists in preventing the symptoms of hypolactasia by following a diet low in lactose or none at all. Therefore, if symptoms of indigestion are detected after consuming unfermented dairy products, it is advisable to carry out a genetic test for lactase activity in order to avoid attempts at pointless treatment and choose an appropriate diet. The test also helps to predict lactose intolerance in children in order to prevent unexpected bowel disorders.

Recommended analyzes

Info Field »All about lactose intolerance. Scientific view

How does milk sugar intolerance appear, how do the types of hypolactasia differ and is it harmful to humans?

It is known that women feed their offspring with breast milk. This is a fairly common practice in the mammalian world. And breast milk also contains lactose – that is, milk sugar. It gives up to 30% of the energy value of milk.

To break down lactose in the small intestine of newborns, a special enzyme is produced – lactase. With age, this process can stop, and not only in children, but also in young mammals. Before the advent of animal husbandry, and even more so the development of the food industry, milk was not available to adults. Therefore, the production of the enzyme was stopped as unnecessary.

When there is no lactase in the body, milk sugar from the small intestine enters the thick one outside of the digested form. That is why, after drinking milk, we may experience increased gas production, cramps, pain or diarrhea. Some also note a headache among the symptoms.

Nature of symptomatology

Lactose is a disaccharide. It is composed of glucose and galactose. The enzyme lactase is designed to break down milk sugar into its constituents. The resulting monosugar enters the bloodstream through the walls of the small intestine. The disaccharide cannot do this, therefore it passes into the large intestine, where it becomes food for the bacteria living there.They are not as delicate as an enzyme. As a result of their meals, gases and water are released. The first – stretches the intestine, the second, getting into the lumen of the intestine, provokes its disorder.

If a special enzyme is not produced in the body, then a liter of milk drunk in the morning can unsettle a person for a day. But one cup will be digested without showing symptoms. Moreover, if you divide it into several parts and eat it as milk porridge or other dishes. Lactose, being in the stomach along with solid food, will stay there longer, and will enter the intestines fractionally.This eliminates unwanted consequences. However, in some people, the sensitivity is so high that milk, even in small quantities, just like cheese and butter, is upset.

Genetic intolerance

Lactose intolerance can be congenital or acquired. The first, in turn, is subdivided into alactasia and primary hypolactasia.

Alactasia – total absence of the enzyme necessary for the breakdown of lactose from birth.It is a disease caused by the destruction of the lactase gene. Before the advent of trouble-free formulas, newborns with alactasia died. It’s good that this is a rather rare ailment.

Often, babies have a functional immaturity of the enzyme system, which in turn also gives rise to milk sugar intolerance. The phenomenon is temporary.

Primary hypolactasia is associated with the fact that during growing up, the activity of the lactase gene decreases, as does the synthesis of the enzyme.

Secondary hypolactasia – acquired intolerance. Appears in the presence of worms and other parasites or due to certain diseases, as well as surgical interventions. It is possible to eliminate intolerance if you remove the causes of its occurrence.

In the 70s, it was believed that lactose intolerance, widespread among some peoples, was a variant of the norm, determined by genetics. In the early 2000s, scientists from Finland identified a specific region in front of the enzyme gene in the human genome.From him, according to researchers, depends on whether an adult will produce lactase or not. Such sites exist in front of all genes. They do not encode a protein, but they determine the performance of a gene.

Another region in front of the lactase gene indicates certain cells of the mucous membrane of the small intestine in which the enzyme will be produced.

Similar areas are like a genetic text composed of nucleotides. The first, 100 nucleotides long, determines the age at which the gene stops working. In people of the European type, the nucleotide C (cytosine) at position LCT-13910 indicates a stop in the production of the enzyme with age. If T (thymine) is in this place, then the enzyme will be produced in adulthood. We get two copies of the lactose gene from both parents. In order to drink milk throughout life, it is enough for at least one of them to be a worker.

How to Diagnose Intolerance

The surest way to find out if the enzyme lactase is secreted in the small intestine is to take a biopsy and measure the activity of the lactase present there.It is clear that this procedure is difficult to perform and it is not worth carrying out it simply at the request of the patient. Therefore, to determine intolerance, other methods are used that indicate it only indirectly.

One option is to drink 50 grams of lactose dissolved in 0.5 liters of water on an empty stomach. This amount of milk sugar is found in a liter of whole milk. The test is performed in a clinical setting. Before him, the patient is measured the level of glucose in the blood. The second time – 40 minutes later.If the lactose has been broken down and the monosugar is absorbed into the blood, then the second time the glucometer has a higher blood glucose level.

If the numbers remain the same, then the lactose has not broken down, therefore, the enzyme is not produced or is produced in insufficient quantities. This can be confirmed by unpleasant symptoms in the abdomen. Activated carbon helps to eliminate them. Another way is to compare not blood sugar levels, but the amount of galactose in urine or exhaled hydrogen using special devices.

After scientists discovered the LCT-13910 site, it became possible to determine lactose intolerance with its help. For this, mucous cells are scraped from the inner surface of the cheek or saliva is taken for analysis. DNA is isolated from the collected materials, which gives the answer to the question. This analysis takes only a few hours to prepare. But he cannot show whether the gene is switched off in a teenager and reveal the presence of secondary hypolactasia.

Age of gene deactivation

According to numerous studies carried out by geneticists and doctors around the world, they have shown that 98% of the inhabitants of Southeast Asia suffer from hypolactasia.Their enzyme ceases to be produced in 5-6 years. In Finland, these numbers are much higher; on average, a gene works up to 22-25 years.

Scientists have compared the gene variant and lactase activity in people of different ages. In our country, such a study also took place. Here are his results: up to the age of 22, all genotypes consume whole milk with the same frequency, then it drops sharply in those who have a genetic predisposition to turn off the gene. It was not possible to determine the age at which lactose intolerance begins to develop only in the indigenous population of the Caucasus and Siberia.Most of them suffer from primary hypolactasia. But since when is not known.

Intolerance and health

About half of all those who are lactose intolerant are not even aware of it. Someone – because they do not like milk and do not eat it. Someone – drinks, but does not associate ailments with it.

A person with an intolerance can exclude foods with lactose from the diet, it is safe for his health. Milk sugar is found not only in milk, it is also present in instant foods, confectionery and meat products.Even certain medicines contain lactose.

The milk sugar content in fermented milk products is lower than in milk itself due to lactic acid bacteria. But they can also cause a reaction in the body.

Besides lactose, milk contains calcium. With its deficiency and a lack of vitamin D, which helps the microelement to be absorbed, in the elderly, the bone mineral density decreases, they more often get fractures. Danish scientists also found that people with genetically determined hypolactasia also often experience a decrease in bone mineral density in the femoral neck when compared with those who can drink milk. But the discrepancy in the figures is small. However, this study did not comment on whether dairy products were substituted for the first group of subjects with calcium and vitamin supplements. For this reason, it is impossible to say exactly how hypolactasia affects the state of the bones.

But we can confidently talk about the unpleasant consequences that arise in those who drink milk, despite hypolactasia. Even with small amounts and little expressed symptoms, there are disorders in the absorption of nutrients in the intestine.

Lactose replacement

If the patient is lactose intolerant, he can drink lactose-free milk or drink lactase tablets. This decision should be made by the doctor.

Primary hypolactasia and milk allergy

Allergies can be caused by milk proteins, not sugar. Its symptoms are more reminiscent of a common allergic reaction: skin rashes, nasal flow, or Quincke’s edema. Hypolactasia does not provoke such manifestations. However, the elimination of milk from the diet will be a panacea for both diseases. In case of allergies, it is also worth avoiding products with milk proteins, and in case of hypolactasia – with its sugar.

Lactose intolerance and skin color

For the first time, the difference in the ability to digest milk among representatives of different races was recorded in 1965. Then 73% of blacks were lactose intolerant. For comparison, in the control group of white-sided – only 16 percent. Then this was explained by the consequence of the disease or the state of the enzyme inhibited by the national cuisine.But today it is becoming apparent that the presence of lactose intolerance and skin color are unrelated. It is determined by the ecological conditions of our ancestors and the prevalence of animal husbandry. By the way, once in Rome, constipation was treated with milk. The mare was especially helpful. Later it became known that its milk sugar content is 1.5 times higher.

When scientists conducted DNA studies of ancient skeletons, they found that everyone in Europe suffered from lactose intolerance until 4-6 thousand years ago. This was shown by the C-variant gene. Its mutation to T occurred with the development of dairy farming about 10 thousand years ago.

Lactose intolerance in Russia

The least common primary hypolactasia (36%) occurs in Russians from the north-west of the country. In the South, its level reaches 50 percent. The same figures are for Belarusians and Ukrainians. Siberians and indigenous people of the Far East have hypolactasia at the level of 70–80% and higher. As in the Caucasus, although not all groups have been studied there yet.In the Urals – about 50%.

Treatment of intolerance

Secondary hypolactasia is treatable if the disease that caused it is eliminated. Genetically determined hypolactasia can disappear only if the gene is replaced. Primary hypolactasia is considered a normal variant. It requires adherence to a certain diet that excludes foods with lactose.

Lactase deficiency / Blog / Clinic EXPERT

In recent years, the topic of milk intolerance has been actively discussed in the media, on social networks, on forums. “Milk is harmful”, “milk should be abandoned” – these and similar statements are often not supported by any convincing evidence.

Harm most often means the appearance of some unpleasant symptoms (nausea, bloating, diarrhea) after eating milk and dairy products. Since such a situation is indeed possible, especially in adults, milk is automatically recognized as an undesirable food in the eyes of the general public. How are things really? Let’s try to understand from the point of view of evidence-based medicine.

Lactose and lactase: what happens to them in the human body?

If we discard the true allergy to milk protein (most often cow), then the vast majority of cases of poor milk tolerance are due to the so-called lactase deficiency. What is this disease? Let’s start from the very beginning.

In addition to fats and proteins, the milk of mammals (including humans) contains carbohydrates, primarily milk sugar lactose .Lactose consists of two molecules of simple sugars – glucose and galactose, linked together by a special bond. In order for lactose to be assimilated by humans, this connection must be broken. Only then can the formed simple sugars, glucose and galactose, be easily absorbed in the small intestine.

The process of cleaving a bond within a lactose molecule is possible only with the presence of a special enzyme – lactase . The names are similar: the enzyme lactase breaks down the milk sugar lactose. This enzyme is located on the surface of the villi of the small intestine.

In humans and most mammals, the activity of the lactase enzyme is maximal after birth, which allows assimilation of a large amount of milk, which in the first months is the only source of food for the newborn. After the termination of breastfeeding, the activity of lactase gradually fades away, as a person switches to an adult type of diet, where milk and dairy products are only a small part of the diet.

In some people, the decrease in the activity of this enzyme occurs very quickly, in some it is gradual, and a certain part of people retain a high activity of lactase for a long time. What does it depend on?

It is known that the ability of lactase to break down milk sugar lactose is regulated by a special gene. More precisely, two genes. One gene (LCT) encodes the enzyme lactase, without which it simply could not be produced. The second gene located nearby is called MCM6, and its task is to regulate the activity of the LCT gene.

For example, it is known that the variant (genotype) of the MCM6 gene, designated as C / C, is associated with low activity of the LCT gene, which leads to early intolerance to milk sugar.In the T / T genotype, the LCT gene activity is high, even in adulthood. The C / T genotype is the most common variant and is most likely to develop into lactose intolerance in middle age.

This information is very important because it is now possible to assess the MCM6 gene in laboratories.

So, the activity of the lactase enzyme is regulated by the gene, with age the probability of a decrease in this activity increases. What happens to the milk sugar lactose if there is not enough enzyme to break it down in the small intestine? Some of the lactose will still be broken down and absorbed in the small intestine. The remaining unbroken lactose molecules will move further down the small intestine and eventually enter the large intestine. In the process of such a movement, due to its high osmotic activity, lactose pulls on water molecules, increasing the amount of fluid in the intestinal lumen, which increases the risk of developing diarrhea . Milk sugar that has entered the colon is an excellent nutrient substrate for local bacteria, which actively begin to break it down, producing gases. Gas and bloating is a common symptom in these patients.In addition, individuals with impaired lactose breakdown and absorption may experience mild abdominal pain, nausea, and other unpleasant symptoms.

Summarizing all of the above: low activity of the enzyme lactase leads to impaired absorption of lactose in the small intestine. This condition is called in medicine “ lactase deficiency” . Lactase deficiency, which occurs over time in adults, also has a second name – adult hypolactasia. This article will focus on this most common variant of lactase deficiency.We leave aside congenital lactase deficiency (an extremely rare disease of newborns) and secondary lactase deficiency (arises as a result of a number of gastroenterological, infectious and other diseases).

Prevalence of lactase deficiency

Modern studies demonstrate a high prevalence of lactase deficiency in adults around the world – on average, 70% of the population poorly absorbs milk sugar.The remaining 30%, however, retain the ability to break down lactose at a high level and do not experience any unpleasant symptoms. There is a cultural and historical hypothesis of the formation of such stability. According to this hypothesis, about 10 thousand years ago, a gene mutation (yes, the same MSM6 gene) arose and took root in the population of northern Europeans, which allows people to tolerate milk well even in adulthood. It was during this period that animal husbandry began to develop actively, and dairy products began to be widely used in the human diet. Those who had the “desired” mutation ate more nutritious food, which means they had a better chance of surviving in harsh conditions.

Research shows that crops that in the past relied on livestock and dairy products are more likely to show good lactose tolerance than populations with low dairy consumption. For example, in Southeast Asia,> 90% of individuals have a lactase enzyme deficiency in adulthood. In contrast, in Scandinavian countries, the prevalence of lactase deficiency is about 10%.

In the Russian Federation, the prevalence of lactase deficiency is approximately 60%.

Diagnosis of lactase deficiency

The presence of typical symptoms of lactase deficiency: loose stools, bloating, increased gas production, nausea after consuming milk and dairy products often allows one to suspect this diagnosis even before going to the doctor, or at least before what -or tests.

Yes, sometimes a patient, turning to a gastroenterologist, says: “If I drink a glass of cow’s milk, then I will definitely have diarrhea after which time. If I don’t drink milk, everything is always good. ” A typical picture of lactase deficiency usually does not require additional research. In practice, most cases of lactose intolerance are lubricated, disguised as other problems and diseases. Bloating without stool disturbances or mushy stools some time after eating – but you never know what this may be due to? And if a person consumes milk or dairy products every day, then it is usually not possible to establish or exclude a diagnosis of lactase deficiency only on the basis of symptoms.

How can lactase deficiency be established in this case?

Option one : elimination diet.

By eliminating from the diet all milk products (namely from milk, and not those that “contain milk powder”) for a certain period, you can see the complete or almost complete disappearance of symptoms. Most likely, it was milk sugar in the composition of products that caused their appearance. You can test this hypothesis by gradually introducing dairy products or milk into the diet.

Option two : hydrogen breath test with lactose.

The test is based on determining the concentration of hydrogen in the exhaled air. Hydrogen is a gas that is released when bacteria in the colon break down some carbohydrates. To do this, carbohydrates must enter the large intestine, where they are processed to form gas. As a result, the released hydrogen is rapidly absorbed through the intestinal wall into the bloodstream and delivered to the lungs.

The carbohydrate chosen for the test is the same milk sugar lactose found in animal milk and dairy products.It is this carbohydrate that is poorly broken down with insufficient activity of the lactase enzyme, as a result of which, in patients with lactase deficiency, a sufficiently large amount of lactose reaches the large intestine.

Based on measurements of the concentration of hydrogen in the exhaled air before the start of the test (on an empty stomach) and at certain intervals after the consumption of lactose, a diagnosis of lactase deficiency is made or excluded.

Option three : lactose tolerance test with determination of blood glucose.

The test is based on the knowledge that lactose is a carbohydrate made up of two simple carbohydrates, one of which is glucose. If a person does not have lactase deficiency, then the activity of the lactase enzyme is preserved, that is, the processes of lactose breakdown in the small intestine are preserved. The glucose molecules released during the breakdown are quickly absorbed and enter the bloodstream. An increase in blood glucose levels after consuming milk sugar can be determined in the laboratory. The disadvantage is the invasiveness of the procedure, i.e.e. the need to collect blood samples several times during the test.

Option four : activity of the enzyme lactase in a biopsy specimen of the small intestine.

As we said above, the lactase enzyme is located on the surface of the villi of the small intestine. there are special laboratory kits that allow you to determine the activity of lactase in real time. For this, a biopsy (a piece of tissue) from the duodenum is taken to the patient during gastroscopy.Low enzyme activity may indicate the presence of lactase deficiency in the patient. A relative disadvantage of the method is its invasiveness (the need for gastroscopy).

Option 5 : Study of variants of the MCM6 gene.

This method is now widely used by doctors and is offered by laboratories for the diagnosis of lactase deficiency. However, if you take a critical look at genetic research, you can understand that even the definition of one or another genotype (C / T or C / C) does not mean that the patient has lactase deficiency.We can only talk about the possible risk of its early development with the C / C genotype or the low probability of lactase deficiency with the T / T genotype.

Treatment of lactase deficiency

Since the cause of the onset of symptoms in lactase deficiency is insufficient breakdown of milk sugar (and only it!), The solutions to this problem may be as follows:

  • completely exclude products containing lactose from diet;
  • to drastically reduce the amount of lactose consumed from food.

To date, there is evidence of the positive effects of milk and dairy products on human health. Thus, regular adequate intake of milk / dairy products reduces the risk of developing colon cancer, type 2 diabetes, cardiovascular diseases, including stroke. This food group is an important source of calcium, which is especially valuable for people with osteoporosis. In this regard, the complete exclusion of milk and dairy products by patients with lactase deficiency is undesirable.

An alternative would be to select those dairy products that are low in lactose in a regular serving. It is known that even people with diagnosed lactase deficiency, including those with the C / C genotype, are able to break down a small amount of milk sugar. Symptoms occur when the amount of lactose that has entered the small intestine with food exceeds the capacity of the enzyme system.

In this regard, it is very important to have an idea of ​​how much lactose is contained in different dairy products.We have tried to provide data on some products in the table:

100 ml



90 ml


9 0313

100 g

Product name

Product portion

Lactose content (g)

Cow’s milk 9016 ml



Cow’s milk 3.2%

100 ml


Skimmed cow’s milk

Goat milk

100 ml


Buffalo milk

100 ml

9000 90

Sheep milk

100 ml


Human milk *

100 ml


Lactose-free milk

100 ml

9016 0.5

0 A

9016 9016 9016 9016 9016 9016 9016 9016 0.5

0 A 100 ml


Condensed milk

100 ml




100 ml



90.0 g



100 g


Mozzarella cheese


Sheep cheese

100 g


Cheese3 Ricotta

100 g


Parmesan cheese

100 g



33 Cheese30003




15 ml


Ice cream

15 g 90-600 9000

* Given for comparison

As you can see from the table, the lowest lactose content is in hard cheeses, portioned cream, butter and, of course, in lactose-free milk.Studies show that individuals with lactase deficiency generally tolerate up to 12 grams of lactose per meal. In practice, this amount can be even less and individually for each person.

There are also substitutes for animal milk, usually of plant origin. For example, rice milk, soy milk, coconut milk, almond milk, hazelnut milk, macadamia nut milk, etc. These products do not contain lactose, despite the word “milk” in the name.

In addition, some probiotics, as well as dietary supplements containing the enzyme lactase, can help in solving the problem of lactase deficiency.


Lactase deficiency in adulthood is a genetically programmed condition that leads to a decrease in the activity of the lactase enzyme in 60-70% of people and, often, to the appearance of unwanted symptoms when consuming milk and dairy products. These individuals need a dietary adjustment with the choice of those foods that contain little lactose. At the same time, 30% of the world’s population, even in adulthood, tolerate the usual amount of lactose well and, in this regard, do not need any dietary restrictions.The complete elimination of milk and dairy products is undesirable due to their positive effects on human health.

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The trend towards healthy eating allows you to choose different approaches. One of them encourages people to switch to gluten-free and lactose-free menus. Dietitian and nutritionist Marina Linkevicienė told RIAMO how it is justified, what health consequences it can lead and what foods should be avoided for people with food intolerances.

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Gluten and Gluten Intolerances

This complex protein is found in cereals such as wheat, barley, oats and rye. And also in the products that are produced from these grains: semolina, wheat, barley and oatmeal, bakery and pasta. Gluten translated from Latin means “glue”, the expert explains. In a more understandable sense for us, it is gluten. It is formed when flour raw materials come into contact with water and glues the grains, due to which the dough is kneaded, and the baked goods become fluffy and stored longer.

“The society has divided into two camps regarding the benefits and harms of gluten and periodically organizes information wars. Apparently, they will never end. Gluten-free is already a trend. The incomes of producers of gluten free products are growing exponentially, ”says nutritionist Marina Linkevičienė.

According to her, medicine distinguishes two types of intolerance to this protein: congenital and acquired.

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Congenital gluten intolerance

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Celiac disease is a genetically determined negative reaction to wheat protein. It is quite rare – only 3% of the population of our planet suffer from this disease. Celiac disease is a chronic autoimmune disease characterized by atrophy of the mucous membrane of the small intestine, that is, impaired absorption.

“With this diagnosis, it is necessary to completely exclude gluten-containing foods from the diet. And that’s the problem. Because manufacturers add gluten to many products.For example, in sausages, chips, cutlets and other semi-finished meat products, as well as in confectionery, ice cream and cheese. At the same time, manufacturers may deliberately or accidentally not indicate gluten in the product on the label. And there is only one recommendation for making the menu – homemade food, ”warns the nutritionist.

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Acquired gluten intolerance

Marina Linkevičienė says that there is no absolute truth in modern medicine and quotes Paracelsus, who owns the phrase: “ Everything is poison, everything is a medicine; both are determined by the dose. “ In the case of gluten, this is true. Gluten passes through the intestines trasitarily, damaging its villi and sticking them together. The intensification of the process with the abundant use of gluten-containing foods can result in a disruption in the functioning of the organ, which ceases to cope with its function and will respond with indigestion, bloating, and pain. This is the acquired form of the disease.

Expert recommends:

“In contrast to congenital, there is prevention for acquired gluten intolerance.And it consists in special attention to the quality of the products on your table. A healthy diet is a balanced menu with fruits and vegetables, meat and grains. And at the same time, the consumption of industrial products is limited ”.

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Should a healthy person give up gluten

The expert notes that the protein itself is distinguished by its valuable composition – it contains a number of essential amino acids for us.Together they are responsible for digestion, tissue regenerative functions, and hemoglobin production.

“Patients often come to see patients, especially girls and women, who suffer from iron deficiency anemia. Moreover, both in explicit and latent form. And as a rule, many of them adhere to all kinds of diets, including gluten-free, ”Marina Linkevicienė shares her experience.

For a non-celiac person voluntarily quitting gluten is unjustified.Firstly, it is an infringement of one’s own body in substances useful for it. Secondly, it will not have the desired effect if you, for example, plan to lose weight with trendy gluten-free products. The lack of gluten does not affect calories. But other not always useful additives are added to such food: for consistency, taste, and increasing shelf life.

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Lactose and lactase: subtleties of terminology

“Just one letter, and such a big difference.Lactose is milk sugar found in milk and milk products. Lactase is an enzyme that helps break it down; it is produced in the small intestine. In other words, lactose intolerance is a consequence of lactase deficiency, ”says the expert.

The reason for the deficiency is a decrease in the production or complete absence of this enzyme. If lactose enters the intestine and is not broken down there, then a clinical picture is observed: bloating, pain, increased gas production, intestinal upset.According to the nutritionist, lactase deficiency is primary and secondary.

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Primary lactase deficiency

The condition is associated with a congenital decrease in enzyme activity. The reasons are genetic and ethnic, historically influenced by the traditional diet of our ancestors. Lactase seems to be there, but it does not have enough strength for proper splitting. In this case, the cells of the small intestine – enterocytes, with the help of which cleavage should occur, are not damaged.This leads to lactose intolerance, explains Marina Linkeviciene and warns:

“When identifying symptoms, it is important that the physician differentiates the form of the disease. An appropriate blood test for this enzyme allows you to diagnose. If this is a genetic, primary form, then the use of milk, cottage cheese, cheese and other dairy products is contraindicated. ”

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Secondary lactase deficiency

Decrease in lactase activity can be acquired.This is due to damage to enterocytes. That is, as a consequence of pathological inflammatory processes in the small intestine caused by bacteria and viruses, toxic damage from taking certain drugs, as well as food allergies, the same celiac disease, for example, explains the nutritionist and notes:

“This acquired state is being corrected. It is enough to eliminate the causes, diagnose and cure the disease. After some time, the body will restore the ability to produce the enzyme in the required quantity and quality, and you can return to the use of dairy products. “

Marina Linkevichiene recommends not to use dietary supplements, enzyme and other complexes without the advice of a specialist to replenish the lack of substances caused by the rejection of any products:

“First, we need diagnostics. At least once a year, you need to donate blood for biochemical analysis. Secondly, you can entrust the management of your health and the health of your family, since we are talking about genetic subtleties, to a general practitioner – a family doctor or a competent nutritionist ”.

Lactase deficiency: description, symptoms, diagnosis and treatment

Lactase deficiency or primary lactase deficiency is called a violation of the breakdown of lactose in the body.It occurs due to a deficiency of the enzyme lactase, which is located in the mucous membrane of the small intestine, and is accompanied by clinical symptoms. Lactase deficiency is triggered by a genetically determined decrease in enzyme production and manifests itself in the body’s inability to absorb lactose (milk sugar).

Lactase is produced by the body in large quantities after the birth of a child, but by the end of the first year of a baby’s life, its production is noticeably reduced. This is called primary (or congenital) lactase deficiency with late onset, inherited in an autosomal recessive manner.

After eating foods containing lactose (usually dairy products and whole milk), patients develop nonspecific abdominal symptoms – nausea, upset stools, and bloating. However, lactose nowadays is found not only in milk and dairy products, but also in other food products (meat, confectionery), in the pharmaceutical industry (as an excipient).

Types of lactase deficiency

It is important to distinguish between primary and secondary (acquired) lactase deficiency: in the second case, it develops as a result of damage to the mucous membrane of the small intestine, arising from any chronic or acute disease.Damage can occur during immune (intolerance to the protein contained in cow’s milk), inflammatory and infectious (intestinal infection) processes in the intestine, as well as with atrophic changes.

This disorder should not be confused with congenital lactase deficiency, which is a rare genetic disorder: its symptoms appear immediately after birth and are directly related to the initiation of breastfeeding.

Symptoms of lactase deficiency

In case of lactase deficiency, the patient develops the following intestinal symptoms after taking milk and dairy products:

  • bloating;
  • rumbling;
  • 90,049 abdominal pain;

  • flatulence;
  • diarrhea.

The patient may feel sick. His stool becomes mushy or liquid, acquires a light yellow color, and has a sour odor.

Who is at risk for lactase deficiency?

  1. People whose relatives have an intolerance to milk and dairy products.
  2. Specific Ethnic Groups: This condition is most common in Southeast Asia, Africa and North America. Among Russians, lactase deficiency is observed in about 16%.
  3. This condition is extremely rare in the first year of life: as a rule, lactose intolerance develops with adulthood.

Diagnosis of lactase deficiency

To diagnose the disease, genealogical data, coprogram results and determination of the level of carbohydrates in feces are used.

No less important for diagnostics is the conduct of a molecular genetic study, which makes it possible to identify a predisposition to this disease.The results of this analysis also allow you to establish the causes of the disease and select an appropriate diet.

In case of refusal of milk and severe clinical manifestations, it is also extremely important to establish the calcium content in urine and serum.

Treatment of lactase deficiency

Specialists prescribe diet therapy to the patient, in which the amount of foods that contain lactose is limited in the diet. If necessary, enzyme preparations are prescribed that can break down lactose.

It is possible to eat lactose-free fermented milk products, as well as products in which the amount of lactose is reduced (curdled milk, yoghurts), hard cheeses, butter and cottage cheese.

When following a dairy-free diet, it is important to pay attention to the amount of calcium intake into the body, if necessary compensating it with medications or other foods with a high content of this substance.

In young children, lactase deficiency is often combined with intolerance to proteins found in cow’s milk.In this case, they are prescribed special mixtures based on a complete hydrolyzate of milk protein.

Specialists can also prescribe to patients antidiarrheal and enzymatic preparations, vitamin complexes, as well as vitamin D preparations, and preparations capable of restoring the intestinal biocenosis.

Prevention of lactase deficiency

As a prophylaxis of this disease, it is necessary to prevent the symptoms of hypolactasia. This is done using a diet that is completely lactose free or low in content.Therefore, in the event that a patient has digestive disorders after eating unfermented dairy products, it is necessary to carry out a genetic test for lactase activity: it will allow you to choose a suitable diet and avoid attempts at pointless treatment. This test can also be used to predict lactose intolerance in children in order to avoid unexpected intestinal disturbances.

90,000 Lactase deficiency, food allergy – Symptoms and treatment

Today, such a diagnosis as lactase deficiency has become very “fashionable” and is often unjustifiably given to children of different age categories.This often becomes the reason for the unjustified transfer of the child from breastfeeding to artificial, early introduction of complementary foods and long-term treatment of the child from a disease that he does not have.

Lactase deficiency or lactose intolerance is a condition in which an insufficient amount of the enzyme lactase is produced in the intestine in order to digest milk sugar (lactose).

Lactose is very important for babies in the first months of life because for these babies breast milk or formula is the main food.Lactose is the main source of energy for a small organism. It is also used for the proper growth and development of all organs and systems. Therefore, the problem of lactase deficiency should be given special attention in children of the first year of life.

Symptoms of lactase deficiency in children can be completely different.

Undivided lactose entering the intestines is broken down by bacteria that live there. This leads to the following symptoms:

  • bloating,
  • Frequent loose, foul-smelling stools,
  • regurgitation,
  • anxious baby (baby throws up, bends during feeding, or cries immediately after feeding),
  • allergic skin rash,
  • the child is gaining weight poorly and is lagging behind in development,
  • in older children, abdominal pain is observed without a clear localization.

Other types of food intolerances, such as gluten intolerance or celiac disease, may show the same symptoms.

Due to nonspecific symptoms of lactase deficiency, it is often confused with food allergy , allergy to cow’s milk proteins in children . Despite this, the mechanism of development, diagnosis and treatment of lactase deficiency and allergy to cow’s milk proteins are completely different. Also, one should not forget that there is a combined pathology – this is when a food allergy in children is accompanied by lactase deficiency.

Most often, lactase deficiency in babies is acquired and develops as a result of other diseases, for example, food allergies or celiac disease, and is not an independent or congenital condition. And after treating the aforementioned conditions, the body’s ability to digest lactose can be restored. Only after eliminating the cause of lactose intolerance can we talk about solving the problem.

Gastrolyzer® – the first breath test in Ukraine for the diagnosis of lactase deficiency and other types of food intolerance, presented at the FxMed Clinic.

Hydrogen breath test is a painless method for determining the level of hydrogen, which is formed by the breakdown of sugar by intestinal bacteria, is then absorbed into the blood and can be measured in the exhaled air.

Breath test Gastrolyzer® is known worldwide as the “ gold” standard for diagnosing lactase deficiency , many types of food intolerance and other diseases of the gastrointestinal tract (overgrowth syndrome (SIBO), irritable bowel syndrome) and is recommended by leading European specialists.

Breathing hydrogen test reveals:
  • lactase deficiency
  • fructose intolerance
  • intolerance to sorbitol (sweetener)
  • definition of transit time in the small intestine
  • Bacterial Overgrowth Syndrome (SIBO)

The technique of the test is quite simple and can be performed on children of all ages. The presence of a mask allows testing in young children.

Treatment of lactase deficiency

It is based on a dairy-free diet and lactase enzyme replacement therapy. The complete exclusion of dairy products from the diet, which is most often prescribed for children with lactase deficiency, is not the best way to solve the problem.

Dairy products are a source of calcium, vitamin D, phosphorus and other trace elements necessary for the normal growth and development of a child. In this case, it is better to eat lactose-free or low-lactose foods.

Treatment of lactase deficiency in children of the first year of life

For children with congenital lactase deficiency, the only treatment method is to transfer the child to therapeutic lactose-free mixtures. In children with acquired lactase deficiency, it is necessary to establish the cause and eliminate it.

For formula-fed children, medicinal lactose-free mixtures are most often prescribed.

Questions and Answers

Can lactase deficiency be diagnosed with a dairy-free diet?

The disappearance of symptoms after excluding dairy products from the diet and their resumption after re-introduction does not always indicate lactase deficiency.It must be remembered that the same symptoms are accompanied by an allergy to cow’s milk proteins.

Is it justified to transfer a child to artificial feeding (lactose-free formulas) if lactase deficiency is suspected?

Can often be unwarranted. Only a very small percentage of children with congenital lactase deficiency should be fed lactose-free formulas. For breastfed babies, lactase preparations are often prescribed and mixed with breast milk.

What are the main causes of lactase deficiency in young children?

The main causes of lactase deficiency in infants of the first year of life are food allergies, including allergy to cow’s milk proteins, food intolerances and celiac disease. Laboratory methods of examination (molecular allergy diagnostics, tests for allergens, tests for food intolerance) help to establish the exact cause of acquired lactase deficiency.

90,000 Lactose intolerance: causes, symptoms, treatment

We all remember from distant childhood the instructions of our beloved grandmothers: “Drink, children, milk – you will be healthy!” Indeed, milk is one of the best sources of calcium, a guarantee of overall health and strengthening of bones.But what if the body does not perceive milk, reacts badly to it, which causes, at least, terrible discomfort? Let’s figure this out together.

What is “lactose intolerance”

Derived from a combination of glucose and galactose, lactose is a sugar disaccharide found in milk and most other dairy products. Lactose is nutritionally beneficial due to its ability to generate energy through slow hydrolysis, enhances the absorption of minerals, and supports healthy gut bacteria needed for proper digestion.Lactose is added to baby food because human milk contains lactose and contributes to the health of babies.

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Lactose intolerance is not an allergy

Lactose intolerance is a genetic disorder that prevents a person from digesting lactose. Caused by a deficiency of lactase, an enzyme essential for the breakdown and assimilation of lactose, lactose intolerance is not an allergy, but a reaction of the immune system to excessive amounts of milk protein in the body.People who are lactose intolerant can have both mild and severe symptoms, depending on the amount of lactase in the body.

Types of lactose intolerance

There are three types of lactose intolerance:

  1. primary lactase deficiency;
  2. acquired lactase deficiency;
  3. congenital lactase deficiency.

Primary lactase deficiency is genetic and is present in most people, in contrast to acquired or congenital lactose intolerance. Acquired lactase deficiency affects people suffering from damage to the small intestine from acute diarrhea, gastroenteritis or parasitic infection. Congenital Lactose intolerance is an extremely rare genetic disorder that prevents the development of lactase from birth. Babies with this type of lactase deficiency also cannot digest breast milk. Next, let’s figure out how and when lactose intolerance manifests itself.

Signals that indicate a predisposition to this disease

Symptoms of lactose intolerance include:

  1. convulsions;
  2. 90,049 bloating;

    90,049 nausea;

  3. flatulence;
  4. 90,049 diarrhea;

  5. rumbling stomach;
  6. vomiting.

Read also – 15 ways to get rid of bloating

Signs of lactose intolerance usually appear within an hour after ingestion of milk or dairy products. The severity of symptoms increases with lactose consumption. However, most people with lactose deficiency can tolerate a certain amount of lactose without experiencing unpleasant symptoms if they limit the amount of lactose they consume at a time.

Medical tests for lactose intolerance

There is a special medical test for lactose intolerance.Assessment of lactose intolerance is based on inhalation of hydrogen and / or a blood glucose test, which determine the degree of lactase deficiency. People undergoing a hydrogen test take 25 grams of lactose in water and are then asked to breathe into a gas chromatograph.

If there is not enough lactase to break down lactose, intestinal bacteria metabolize lactose and produce hydrogen and methane. Finding high levels of hydrogen and methane in a person’s breath means they are likely lactose intolerant.

Causes of lactose intolerance in adults

In adults, lactose indigestion occurs because the gene responsible for lactase production declines as we age. On the other hand, people who are genetically predisposed to this condition may experience little or no discomfort after turning 40.

However, because milk is rich in calcium and vitamin D (two nutrients that older people need to prevent osteoporosis), people who avoid this drink and dairy products due to cramps, nausea, and other unpleasant symptoms of lactose intolerance may suffer from for serious health problems such as decreased bone density and tooth loss.

How to deal with this disease

Mild to moderate lactose intolerance can occur without any severe symptoms if milk intake is reduced to one glass per day (skim milk and natural milk contain the same amount of lactose), cheddar or Swiss cheese (both have less lactose than other cheeses) and consuming dairy products with less lactose. Eating food with milk can help reduce cramps and bloating.

Periodically replacing milk with yogurt (which is rich in calcium) can also help people manage their symptoms, because the bacteria found in yogurt actually produce an enzyme needed to break down lactose.

Now you know more about what lactose intolerance is, its causes and how to treat it. Do you have problems with lactose intolerance? How do you deal with this ailment?