What is causing autophony

What is lactose intolerance?

Not everyone is able to break down and use lactose. In the case of lactose intolerance (milk sugar intolerance) there is a deficiency in the enzyme lactase. As a result, the lactose in the small intestine cannot be broken down and digested naturally.

The lactose then reaches the large intestine undigested, where it is absorbed by bacteria and processed into lactic acid, acetic acid and various gases such as methane and carbon dioxide. These substances lead to the symptoms typical of lactose intolerance. After consuming milk and dairy products, those affected suffer from bloating, abdominal cramps, gas and diarrhea.

Lactose intolerance should not be confused with a milk allergy. The allergy is a reaction of the immune system to a protein that is foreign to the body. Milk contains various proteins (casein, whey proteins). Not every allergy sufferer reacts to all proteins, so sometimes boiled milk or sour milk products are tolerated despite a milk allergy.

How common is lactose intolerance?

Healthy infants still produce enough lactase while they are breastfeeding. Only when switching from milk to solid food does the production of lactase decrease. Lactase deficiency occurs worldwide in adulthood. How much lactase the body then still produces varies in the different population groups.

Lactose intolerance is particularly common in Africa and Asia. It affects more than 90 percent of the adult population there. For this reason, Asian cuisine completely dispenses with cow's milk and dairy products.

About ten percent of Europeans and white Americans are lactase deficient in adulthood. The number has increased significantly in recent years. The ability to digest lactose decreases with age. Around 70 percent of Europeans by the age of 60 can no longer digest lactose. Through better education and information from doctors, medical professionals and those affected, people with gastrointestinal complaints are being examined more and more specifically for lactose intolerance.

What is the cause of lactose intolerance?

There are several forms of lactose intolerance.

Primary lactose intolerance

  • Endemic lactose intolerance: This most common form of lactose intolerance is inherited. Mainly residents of warmer regions of the world are affected. It usually occurs after the age of five and is capable of regression.
  • Congenital lactase deficiency: this condition is rare. This is due to a genetic defect that means that lactase is not active or is only weakly active. The typical symptoms of lactose intolerance already appear in infancy. The infants affected react very strongly to the smallest amounts of lactose. Without treatment, severe developmental damage can occur. Newborns with a congenital lactase deficiency need a special diet, because lactose is usually their only source of energy.
  • Developmental lactase deficiency: This rarely occurs in premature children and is capable of regression.

Secondary lactose intolerance

The secondary, acquired lactose intolerance has no hereditary cause. The cause of the lactose intolerance lies in diseases of the small intestine (for example gastrointestinal infections or chronic inflammatory bowel diseases such as Crohn's disease). They can damage the parts of the small intestine (microvilli) that are responsible for the production of lactase, so that they do not produce any or only insufficiently lactase. The resulting lactase deficiency can be temporary or lifelong. If the underlying disease is treated successfully, it is possible that the lactase deficiency will regress again.

Secondary lactose intolerance can also be caused by taking certain medications, such as antibiotics (drugs that kill bacteria) or cytostatics (drugs that inhibit cell growth and are mainly used in cancer chemotherapy).

What symptoms does lactose intolerance cause?

Which complaints occur and how severe they are varies greatly from person to person and depends, among other things, on the severity of the lactase deficiency and the amount of milk sugar consumed.

Consumption of small amounts of lactose often causes only mild symptoms or no symptoms at all.

The following symptoms can occur immediately or a few hours after consuming large quantities of milk or foods containing lactose:

  • stomach pain
  • nausea
  • malaise
  • Diarrhea
  • Flatulence
  • Cold sweat

In addition to these main symptoms, unspecific complaints such as headaches, exhaustion, sleep disorders and depressive moods can also occur.

Osteoporosis can also occur in people with a lactase deficiency. The cause is probably that these people consume very little or no milk and thus take in too little calcium.

How is lactose intolerance recognized?

The person concerned often notices that he cannot tolerate milk or foods containing lactose. The occurrence of symptoms after consuming milk and the freedom from symptoms when milk and milk products are completely avoided (milk abstinence) are therefore important for the diagnosis.

A diet test can confirm suspected lactose intolerance. The patients must adhere to a consistent diet for several days, in which lactose is strictly excluded. If there is actually a lactose intolerance, the symptoms will go away.

The doctor can use various tests to detect or rule out lactose intolerance.

Lactose tolerance test

In this test, the patient receives 50 grams of pure lactose, which he has to drink with a little water. If he is lactose intolerant, his blood sugar level does not rise, or only slightly, because the lactose in the intestine cannot be broken down and is therefore not absorbed into the body. Symptoms often arise after the test.

H2 breath test

After drinking a lactose solution on an empty stomach, patients with lactose intolerance breathe more hydrogen (H2) off. The reason for this is that when the undigested (not split) lactose is broken down by the intestinal bacteria, hydrogen is released. The hydrogen levels in the air we breathe are measured using a device. In addition, complaints can occur.

Genetic test

With the help of a swab of the cheek mucosa, the genetic form of lactose intolerance can be proven.

What can you do if you are lactose intolerant?

At this point in time, there is no way to treat the cause of your lactose intolerance.

Mild complaints can be relieved with drugs that contain the missing lactase. These can be taken as tablets or chewing tablets immediately before consuming dairy foods. You can get them without a prescription in pharmacies, sometimes also in health food stores. The dosage depends on the one hand on the lactose content of the meal and on the other hand on the severity of the lactose intolerance. Each individual should find out the individual dosage for themselves, preferably in close cooperation with their doctor.

Foods to Avoid

If dairy products cause severe discomfort, those affected should not eat these foods or only eat them in small amounts:

  • Whole milk, condensed milk, dry milk powder and whipped cream
  • Chocolate, milk ice cream, puddings and cream dishes
  • butter

Pay attention to the lactose content of:

  • Pasta such as milk rolls and pastries, cakes and pies
  • Sausage products, ready meals, salad dressings and sweeteners
  • Medication (especially tablets)


  • Fully ripe hard cheeses (e.g. Emmentaler, Appenzeller, Brie, Camembert and sheep's cheese) usually do not cause any symptoms, as the lactose is broken down during the ripening process.
  • Even relatively lactose-rich sour milk products are individually well tolerated. The lactic acid bacteria in yoghurt, sour milk, kefir & Co. break down large amounts of lactose in the intestine and thus make the body's own lactase largely "superfluous" for the digestion of lactose. However, this only applies to products that have not been heated, as the lactic acid bacteria enzyme becomes inactive when heated.

Since milk and dairy products contain a high proportion of calcium, which is very important for bone structure, care should be taken to ensure adequate calcium intake in an elimination diet. For example, meat, broccoli, kale, tomatoes, tofu and soy products are high in calcium. Calcium supplements in powder or effervescent tablet form are also a way of meeting daily calcium requirements.

Alternatives to cow's milk and dairy products are soy products, rice and coconut milk.

Lactose-free milk and dairy products are increasingly being sold in health food stores and occasionally in supermarkets. Milk and milk products fortified directly with lactase are also offered.