Lactose intolerance – Symptoms & causes

Overview

People with lactose intolerance are unable to fully digest the sugar (lactose) in milk. As a result, they have diarrhea, gas and bloating after eating or drinking dairy products. The condition, which is also called lactose malabsorption, is usually harmless, but its symptoms can be uncomfortable.

Too little of an enzyme produced in your small intestine (lactase) is usually responsible for lactose intolerance. You can have low levels of lactase and still be able to digest milk products. But if your levels are too low you become lactose intolerant, leading to symptoms after you eat or drink dairy.

Colon and small intestine

The small intestine and colon are parts of your digestive tract, which processes the foods you eat. The intestines take nutrients from the foods. What isn’t absorbed by the intestines continues along the digestive tract and is passed as stool during a bowel movement.

Most people with lactose intolerance can manage the condition without having to give up all dairy foods.

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Symptoms

The signs and symptoms of lactose intolerance usually begin from 30 minutes to two hours after eating or drinking foods that contain lactose. Common signs and symptoms include:

• Diarrhea
• Nausea, and sometimes, vomiting
• Stomach cramps
• Bloating
• Gas

When to see a doctor

Make an appointment with your doctor if you frequently have symptoms of lactose intolerance after eating dairy foods, particularly if you’re worried about getting enough calcium.

Causes

Lactose intolerance occurs when your small intestine doesn’t produce enough of an enzyme (lactase) to digest milk sugar (lactose).

Normally, lactase turns milk sugar into two simple sugars — glucose and galactose — which are absorbed into the bloodstream through the intestinal lining.

If you’re lactase deficient, lactose in your food moves into the colon instead of being processed and absorbed. In the colon, normal bacteria interact with undigested lactose, causing the signs and symptoms of lactose intolerance.

There are three types of lactose intolerance. Different factors cause the lactase deficiency underlying each type.

Primary lactose intolerance

People who develop primary lactose intolerance — the most common type — start life producing enough lactase. Infants, who get all their nutrition from milk, need lactase.

As children replace milk with other foods, the amount of lactase they produce normally drops, but usually remains high enough to digest the amount of dairy in a typical adult diet. In primary lactose intolerance, lactase production falls off sharply by adulthood, making milk products difficult to digest.

Secondary lactose intolerance

This form of lactose intolerance occurs when your small intestine decreases lactase production after an illness, injury or surgery involving your small intestine. Diseases associated with secondary lactose intolerance include intestinal infection, celiac disease, bacterial overgrowth and Crohn’s disease.

Treatment of the underlying disorder might restore lactase levels and improve signs and symptoms, though it can take time.

Congenital or developmental lactose intolerance

It’s possible, but rare, for babies to be born with lactose intolerance caused by a lack of lactase. This disorder is passed from generation to generation in a pattern of inheritance called autosomal recessive, meaning that both the mother and the father must pass on the same gene variant for a child to be affected. Premature infants can also have lactose intolerance because of an insufficient lactase level.

Risk factors

Factors that can make you or your child more prone to lactose intolerance include:

• Increasing age. Lactose intolerance usually appears in adulthood. The condition is uncommon in babies and young children.
• Ethnicity. Lactose intolerance is most common in people of African, Asian, Hispanic and American Indian descent.
• Premature birth. Infants born prematurely might have reduced levels of lactase because the small intestine doesn’t develop lactase-producing cells until late in the third trimester.
• Diseases affecting the small intestine. Small intestine problems that can cause lactose intolerance include bacterial overgrowth, celiac disease and Crohn’s disease.
• Certain cancer treatments. If you’ve had radiation therapy for cancer in your stomach or you have intestinal complications from chemotherapy, your risk of developing lactose intolerance increases.

Lactose intolerance – Symptoms & causes

Overview

People with lactose intolerance are unable to fully digest the sugar (lactose) in milk. As a result, they have diarrhea, gas and bloating after eating or drinking dairy products. The condition, which is also called lactose malabsorption, is usually harmless, but its symptoms can be uncomfortable.

Too little of an enzyme produced in your small intestine (lactase) is usually responsible for lactose intolerance. You can have low levels of lactase and still be able to digest milk products. But if your levels are too low you become lactose intolerant, leading to symptoms after you eat or drink dairy.

Colon and small intestine

The small intestine and colon are parts of your digestive tract, which processes the foods you eat. The intestines take nutrients from the foods. What isn’t absorbed by the intestines continues along the digestive tract and is passed as stool during a bowel movement.

Most people with lactose intolerance can manage the condition without having to give up all dairy foods.

Products & Services

Symptoms

The signs and symptoms of lactose intolerance usually begin from 30 minutes to two hours after eating or drinking foods that contain lactose. Common signs and symptoms include:

• Diarrhea
• Nausea, and sometimes, vomiting
• Stomach cramps
• Bloating
• Gas

When to see a doctor

Make an appointment with your doctor if you frequently have symptoms of lactose intolerance after eating dairy foods, particularly if you’re worried about getting enough calcium.

Causes

Lactose intolerance occurs when your small intestine doesn’t produce enough of an enzyme (lactase) to digest milk sugar (lactose).

Normally, lactase turns milk sugar into two simple sugars — glucose and galactose — which are absorbed into the bloodstream through the intestinal lining.

If you’re lactase deficient, lactose in your food moves into the colon instead of being processed and absorbed. In the colon, normal bacteria interact with undigested lactose, causing the signs and symptoms of lactose intolerance.

There are three types of lactose intolerance. Different factors cause the lactase deficiency underlying each type.

Primary lactose intolerance

People who develop primary lactose intolerance — the most common type — start life producing enough lactase. Infants, who get all their nutrition from milk, need lactase.

As children replace milk with other foods, the amount of lactase they produce normally drops, but usually remains high enough to digest the amount of dairy in a typical adult diet. In primary lactose intolerance, lactase production falls off sharply by adulthood, making milk products difficult to digest.

Secondary lactose intolerance

This form of lactose intolerance occurs when your small intestine decreases lactase production after an illness, injury or surgery involving your small intestine. Diseases associated with secondary lactose intolerance include intestinal infection, celiac disease, bacterial overgrowth and Crohn’s disease.

Treatment of the underlying disorder might restore lactase levels and improve signs and symptoms, though it can take time.

Congenital or developmental lactose intolerance

It’s possible, but rare, for babies to be born with lactose intolerance caused by a lack of lactase. This disorder is passed from generation to generation in a pattern of inheritance called autosomal recessive, meaning that both the mother and the father must pass on the same gene variant for a child to be affected. Premature infants can also have lactose intolerance because of an insufficient lactase level.

Risk factors

Factors that can make you or your child more prone to lactose intolerance include:

• Increasing age. Lactose intolerance usually appears in adulthood. The condition is uncommon in babies and young children.
• Ethnicity. Lactose intolerance is most common in people of African, Asian, Hispanic and American Indian descent.
• Premature birth. Infants born prematurely might have reduced levels of lactase because the small intestine doesn’t develop lactase-producing cells until late in the third trimester.
• Diseases affecting the small intestine. Small intestine problems that can cause lactose intolerance include bacterial overgrowth, celiac disease and Crohn’s disease.
• Certain cancer treatments. If you’ve had radiation therapy for cancer in your stomach or you have intestinal complications from chemotherapy, your risk of developing lactose intolerance increases.

Symptoms of lactose intolerance in adults and children – MyGenetics Blog

In addition to the DNA test, there are many more ways to test for lactose intolerance. What are these methods, how effective they are, what tests to pass for their passage and in what cases they can be prescribed, read further in this article.

Why are dairy products not digested?

The main active substance in all dairy products, due to which there are problems with their digestibility, is lactose. And the main enzyme of the body, which contributes to its absorption, is called consonantly – lactase. At an early age, if there is no congenital intolerance, all children equally normally absorb dairy products. But over the years, the production of the lactase enzyme may decrease or stop altogether.

Signs of lactose intolerance

It is often possible to confuse poor absorption of milk with an allergy to it. Allergy symptoms are quite common: difficulty breathing, nasal discharge, tearfulness, rash. An allergy can arise from a very small amount of a product containing an allergen, and the use of all milk in this case is completely prohibited. With intolerance, there is no such complete ban.

Symptoms of poor absorption:

• Bloating, grumbling, colic.
• Belching and gas.
• Stool disorders, vomiting.
• In some cases, pain in the abdomen or intestines.

It takes about half an hour to two hours from the moment of eating for the symptoms to appear. The symptoms themselves and the degree of their manifestation depend on the ratio of the amount of dairy products consumed and the amount of lactase present in the body for its absorption, respectively.

Lactose intolerance test

Usually, the diagnosis of lactose intolerance is established by the doctor based on the symptoms voiced by the patient. But, in case of doubt, additional studies may be assigned.

How to identify lactose intolerance

Lactose Curve

A study aimed at collecting data and plotting a comparative graph of glucose (sugar) and lactose levels. The subject drinks on an empty stomach a glass of liquid containing lactose. And for some period, blood samples are taken from him. Samples are analyzed and a schedule is drawn up. If the lactase line does not exceed the glucose line, then conclusions are drawn about the insufficiency of the lactase enzyme.

Small intestine biopsy

One of the outdated methods for testing food digestibility. It consists in the fact that a small area of ​​the small intestine is selected and its sample is taken, which is further investigated. The technique is traumatic and is prescribed less and less, it is not prescribed to children at all.

Fecal analysis for lactose deficiency

This analysis is mainly prescribed to infants as the safest research method. And it is on infants that the most accurate results are obtained. Before taking the test, it is recommended not to change the daily diet of the baby, but to transfer the sample to the laboratory no later than 4 hours from the moment it was taken.

The sample is examined for the presence of a percentage of carbohydrates. If the carbohydrate content is from 0.25% to 0.5%, then this is within the normal range. For a baby, the norm can reach up to 1%.

Hydrogen breath test

It is believed that of all tests, a study for the presence of hydrogen is the most accurate. The testing method consists in the fact that the subjects drink a specially prepared liquid containing lactose, and after a while breathe into a special device. If the device detects hydrogen exhaled by a person, then this 100% confirms problems with absorption. Attention! The analysis is carried out on an empty stomach.

Coprogram

Another method for determining problems with the assimilation of dairy products in children. As with the analysis of stool in infants, before taking a sample, it is necessary to follow the usual diet. The sample must be submitted to the laboratory no later than 12 hours after its receipt.

The biomaterial is analyzed for acidity content. It is believed that if the level of acidity is exceeded, this is a consequence of the fermentation of undigested lactose.

Urine lactose test

The test is not very accurate, but in order to dispel your doubts, it is quite suitable. It is carried out at home and is similar to a pregnancy test. The litmus test paper is wetted in urine and acquires a certain color. The color value must be determined on a special scale.

Blood test for lactose intolerance

If we are talking about the study of blood and urine, then this is an analysis for the content of galactose, a by-product of the breakdown of lactose. At the beginning, a control blood sample is taken from the patient to determine the normal level of galactose, after which they are allowed to take a special mixture and, after a certain time, samples are taken for analysis again.

In what cases an examination is prescribed

Lactose intolerance testing may be ordered if:

• For young children with bowel problems.
• If there are clear symptoms of intolerance.
• To determine the risk of developing osteoporosis.
• In a comprehensive study of the gastrointestinal tract in adults.

Genetic marker

A genetic marker is a gene whose position on the chromosome is precisely known. The main gene responsible for the absorption of lactose by the human body is called MCM6, and it is this gene that is examined during genetic testing. Although the gene itself is not directly involved in the production of lactose, it affects the LAK gene, which is directly involved.

Genetic lactose intolerance

Modern medicine makes it possible to cure all the causes of poor digestion of fermented milk products, except for genetically determined disorders. It remains only to choose where to take a DNA test, which analysis gives the best results and follow the instructions of the doctors exactly.

It is worth noting that in most people (about 80% of humanity), over the years, the loss of the ability to absorb lactose well is genetically determined, and the remaining 20% ​​are a kind of “genetic lucky ones”. However, eliminating all milk from the diet requires replenishing the beneficial substances that it contains through the use of multivitamins.

But there is a downside to multivitamin use: some vitamins and minerals can accumulate, and the wrong dosage can lead to an overabundance and undesirable consequences. You can learn more about exactly how your body is able to absorb vitamins in the MyDetox test.

DNA testing is excellent for accurately diagnosing a problem. Genome analysis will allow you to accurately determine how the body produces lactase: in full, in part, or not at all. You can conduct such a genetic study quickly and inexpensively in our clinic. In the MyGenetics line of tests, you can determine lactose intolerance using the MyWellness panel. And this is equally convenient to do, being in any region of Russia.

Lactose intolerance: causes, symptoms, analysis

Do you suffer from cramps and bloating? Do you hear a rumbling in your stomach? Periodically worried about loose stools? If these signs appear some time after taking milk and milk-containing products, lactose intolerance (hypolactasia) can be assumed.

Why does this pathology occur and can it be avoided? Let’s figure it out.

Lactose (milk sugar) is a substance found in the milk of mammals and humans. The role of lactose in the body is great: it helps the absorption of certain minerals, including calcium, in the intestines, and also promotes the reproduction of lactobacilli necessary for the body.

Normally, in all babies, lactose is broken down in the small intestine by a special enzyme – lactase. With age, the amount of lactase in the body of some people decreases.

The diet of a modern person is difficult to imagine without dairy products, and the presence of this enzyme in the body is extremely important for the normal process of digestion.

The mechanism of development of hypolactasia

Lactose intolerance occurs when there is a complete absence or insufficient amount of lactase. The task of this enzyme is to participate in the conversion of lactose in the small intestine into glucose and galactose. These carbohydrates are able to pass through the intestinal wall into the bloodstream.

With a lack or absence of lactase, milk sugar in an unsplit form enters the large intestine, where it becomes “food” for the bacteria living here. The result of the processing of lactose by bacteria is carbon dioxide, methane, hydrogen and water. The gases formed in the lumen of the large intestine stretch its walls, causing bloating (flatulence) and pain in it, and water causes the development of diarrhea (loose stools).

Lactose intolerance is much less common in children than in adults. It is congenital and acquired. Alactasia, or the complete absence of the enzyme, is associated with a structural disorder of the lactase gene. In this case, the baby should receive lactose-free food from birth. Fortunately, this disease is quite rare. More often one can observe the functional immaturity of the enzyme system of infants, which causes insufficient milk tolerance; some time after birth, the amount of the enzyme increases and the breakdown of lactose improves.

Acute and chronic intestinal infections, immune, inflammatory, atrophic processes in the intestine can lead to secondary (acquired) intolerance to milk sugar.

Factors such as age, ethnicity increase the risk of developing this pathology (in the countries of North America, Africa, Southeast Asia, the percentage of those suffering from hypolactasia is higher), and premature birth.

How does lactose intolerance manifest itself?

Rumbling in the abdomen and its distension, diarrhea, nausea, vomiting, abdominal pain, headaches – these symptoms of lactose intolerance occur in some people an hour after taking whole milk or dairy products (cheese, cottage cheese, kefir, ice cream).

The higher the degree of hypolactasia, the more intense the clinical manifestations. However, it should be remembered that such a reaction of the body may also be due to the use of stale products with an expired shelf life or their incompatibility. In both cases, if you have the symptoms mentioned above, you should consult a doctor.

Diagnosis of lactose intolerance

A biopsy of the small intestine mucosa is a direct way to measure the activity of the lactase enzyme it contains. Due to the trauma and complexity of this study, it is used during operations or other vital interventions.

Genetic tests can identify genes that block lactase production.

One common indirect test for lactose intolerance, among others, is the lactose load test. It is based on a comparison of blood glucose levels in an adult before the study and after ingestion of 50 grams of lactose dissolved in 0.5 liters of water. If lactose is broken down and the resulting glucose is absorbed into the blood, the meter will show an increase in blood glucose. Otherwise, we can conclude that lactase is not working.

How to treat lactose intolerance?

Primary hypolactasia is a kind of normal, not a disease, so there is no specific treatment for this form of lactose intolerance, but a lactose-free diet must be followed. Secondary hypolactasia is corrected in the treatment of the underlying disease that led to its development. Taking the missing enzyme in the form of tablets and drops must be combined with a balanced diet developed by a nutritionist.