Lactose intolerance – causes, symptoms & therapy

Milk sugar (lactose) consists of the molecules lactose and galactose.

Lactose intolerance is based on a malfunction of the lactase enzyme. Lactase is an important enzyme that breaks down milk sugar (lactose) into its individual components (lactose, galactose) in order to be absorbed by the small intestine.

If this does not happen, the sugar molecules have to be broken down by bacteria, which can lead to the typical digestive problems. The severity of the symptoms depends on whether traces of the enzyme lactase, which breaks down lactose, are present or not at all.

Lactose intolerance should not be confused with a milk protein allergy. In the case of a milk protein allergy, the immune system is involved and produces antibodies. The symptoms of lactose intolerance, on the other hand, are only caused by the component lactose contained in milk, the immune system is not involved.

A lactose intolerance is diagnosed via an oral lactose load test in which the person concerned receives 50 g of lactose. It is then checked to what extent the lactose has been absorbed in the small intestine. If this test shows that there is a lactose intolerance, the next steps will be discussed with a doctor.

Causes

The cause of lactose intolerance is the absence or insufficient production of lactase. This digestive enzyme, which is found in the mucous membrane of the small intestine in healthy people, is essential for the necessary splitting of milk sugar into its components (lactose, galactose).If the milk sugar cannot be broken down due to lactose intolerance, it reaches the lower parts of the intestine (large intestine), which is colonized by bacteria .

These bacteria ingest the lactose, releasing larger amounts of gas and organic acids. As a result, in the case of lactose intolerance, water flows into the intestine and increased intestinal movements take place, from which the affected person suffers.

If one takes a closer look at the causes of lactose intolerance, two forms must be distinguished. This is referred to as a primary or secondary lactase deficiency.

Primary lactase deficiency

In the case of primary lactase deficiency, there is initially a hereditary, very rarely occurring metabolic disease and a lactase deficiency that only occurs after weaning. In this form of lactose intolerance, which is widespread worldwide, the lactase activity decreases completely over the course of life.

Secondary lactase deficiency

A secondary lactase deficiency occurs as a side effect of other diseases (e.g. celiac disease or Crohn’s disease ) and is possible at any age. If the disease is treated, the lactose intolerance also disappears.

symptoms and course

Possible signs of lactose intolerance:

• Digestive problems a few minutes to a few hours after consuming milk products

• Bloating ( flatulence ), abdominal pain , stomach cramps ,

• Diarrhea

• nausea , vomiting

• Increased (sometimes painful) urge to defecate

• dizziness

• headache

• Muscle aches

• exhaustion

• fatigue

In the case of lactose intolerance, the consumption of milk or milk products leads to typical digestive problems after a short time. The first symptoms often appear within the first 30 minutes after eating foods containing lactose.

Affected people often suffer from digestive problems, such as: abdominal pain, abdominal colic, feeling of fullness , flatulence, diarrhea, nausea, urge to defecate or stomach growling. Headaches, body aches , fatigue, depression and acne are also possible side effects of lactose intolerance.

Lactose intolerance is usually chronic and cannot be cured. Depending on the level of enzyme activity (lactase), the symptoms also vary in severity. With restricted lactase activity, those affected sometimes notice hardly any symptoms or no symptoms at all. On the other hand, a complete loss of function of the enzyme, even with low lactose, can cause severe symptoms.

Primary lactose intolerance is generally harmless, as there are usually no consequential damages. In contrast, in the case of secondary milk sugar intolerance, serious deficiency symptoms ( iron deficiency , calcium deficiency , vitamin deficiency ) can occur.

Diagnose

The diagnosis of whether lactose intolerance is present or not is also based on the cooperation of the patient, because the doctor is dependent on the description of the symptoms. The knowledge gained from this is the basis for further diagnostic procedures that can be carried out by an internist or gastroenterologist.

The H2 breath test

This test, also known as the hydrogen test, is the preferred diagnostic method to determine any existing lactose intolerance. Before the H2 test, which lasts about 2 hours, the patients are not allowed to eat anything and only drink a little. A little water at most.

As with an alcohol test, the H2 measurement is blown into a measuring device. A lactose solution must then be drunk. The measurement is repeated several times at intervals of approx. 30 minutes. If the hydrogen content is now above a certain value and the typical symptoms occur at the same time, it is very likely that lactose intolerance can be assumed.

The test is considered reliable because due to the insufficient production of the enzyme lactase, the lactose from the food reaches the large intestine uncleaved. When the lactose begins to be fermented there by living bacteria, hydrogen is also produced in addition to the gases, which is transported through the intestinal wall together with the blood to the lungs and exhaled. A healthy organism does not produce hydrogen on an empty stomach. If there is an increase in the H2 measurement, the suspicion of primary or secondary lactose intolerance is confirmed. However, no differentiation between these two intolerances can take place with an H2 test.

The exposure or provocation test

In this test, a glass of milk is drunk on an empty stomach. If the known symptoms appear for a short time, the suspicion of lactose intolerance is confirmed. The suspicion should be confirmed with further tests.

The lactose intolerance test

Here, a glass of water with 25 to 50 grams of dissolved lactose is drunk. If there is enough lactase in the small intestine, the lactose is broken down into mucus sugar (galactose) and glucose (dextrose), which leads to an increase in blood sugar levels (elevated glucose levels in the blood) in the next 2 hours or so. This does not happen with a lactase deficiency.

The genetic test

This is suitable for diagnosing hereditary lactose intolerance. A cheek swab is examined in the laboratory for specific changes in the genetic material. This test can be carried out at the doctor’s or at home. If done privately, the swab should be sent to a laboratory for evaluation.

The small bowel biopsy

A tissue sample from the small intestine can demonstrate reduced lactase activity. This examination is not part of the routine examinations.

complications

Lactose intolerance usually does not cause any serious complications. As long as the affected person avoids lactose-containing foods, there will be no symptoms and the disorder will have no consequences. However, if lactose is ingested, it primarily leads to gastrointestinal problems. Then you have stomach pain, nausea and a feeling of fullness. Due to the water-binding effect of lactose, diarrhea usually occurs. Prolonged diarrhea can lead to dehydration and deficiency symptoms. However, it can also lead to constipation, combined with cramps and the risk of an intestinal blockage.

Treatment of lactose intolerance with lactase tablets carries the risk of side effects such as digestive problems and headaches. In rare cases, allergic reactions can also occur. If lactose intolerance is treated as part of a diet, there are usually no complications. However, deficiency symptoms can occur if the daily diet is not wholesome and balanced. A complete renunciation of milk and milk products can lead to a lack of minerals and vitamins in the long term, which can also lead to deficiency symptoms.

treatment and therapy

As a treatment for lactose intolerance, it is generally recommended to avoid or reduce the consumption of milk and milk products. The extent of lactose intolerance varies from person to person. Some sufferers have to do without lactose altogether so that they do not suffer from any symptoms. Others tolerate lactose if it is consumed in small amounts.

An alternative to conventional dairy products can be lactose-reduced products, which come in a variety of forms (milk, cheese, yoghurt, quark, cream).

Drug treatment of lactose intolerance is possible with chewable tablets or capsules containing lactase, which are available in drugstores or pharmacies. Dosing is difficult to assess as it needs to be tailored to the lactose content of the foods in question and the severity of the lactose intolerance.

Prevention

Since lactose intolerance is not an allergy or a disease, but a food intolerance, it is not possible to prevent it. Nevertheless, you can avoid the symptoms associated with lactose intolerance by avoiding foods containing milk.In addition to typical dairy products such as milk, butter, yoghurt, cheese, quark or margarine, bread and baked goods, chocolate and many ready meals also contain lactose. Even some meat and sausage products and even some medicines contain lactose.

Preventing lactose intolerance is therefore only possible by reducing or avoiding all of these foods if you have symptoms. In addition, targeted nutritional advice can help to live well with lactose intolerance.