Intolerance to milk sugar (lactose intolerance) is one of the most common intestinal disorders. The lactose in food cannot be absorbed and broken down by the intestine. About 10 % of the German population is affected. In Southeast Asia, many more people are affected by lactose intolerance. The reason for this lactose intolerance is the lack or insufficient concentration of the digestive enzyme lactase in the mucous membrane of the small intestine.

The enzyme lactase is needed to break down milk sugar into its individual components (glucose and galactose). The two individual sugars can then be absorbed. If the lactose reaches the large intestine, it is used by intestinal bacteria as an energy source and gases are produced that can be used to diagnose lactose intolerance.
The symptoms of lactose intolerance can vary greatly, and often include abdominal pain, flatulence, diarrhoea, rarely constipation or nausea.
Lactose intolerance can be diagnosed with the lactose H2 breath test. Here, the patient’s breath is examined after ingesting lactose. The increase in hydrogen in the breath, which is formed by the intestinal bacteria during the breakdown of the non-absorbable lactose, is determined.

Treatment options for lactose intolerance

It is very important to significantly reduce the amount of lactose in the diet. However, a completely dairy-free diet is usually not necessary. The amount of dairy products that can still be tolerated cannot be determined by the lactose H2 breath test. As soon as the diagnosis is made, all products containing lactose should be avoided. If this results in complete freedom from symptoms, the amount of lactose that is well tolerated can be carefully tested, as there is usually some residual activity of the lactase enzyme.

Yoghurt is usually well tolerated due to its low lactose content.

What should be considered when choosing food?

Foods containing lactose should be avoided if possible. The diet should include fresh foods such as salads and vegetables, as well as fibre. Sweets and fast food should be avoided. Many ready-made products and medicines can contain lactose.

Foods to avoid with lactose intolerance:

Cow’s milk in any form and all foods made from it.
Cream, coffee cream, condensed milk, cream cheese preparations, whey, quark, kefir, processed cheese
Bread and bakery products made with milk, e.g. rusks, milk rolls, plaits, cakes, waffles.

Suitable foods for lactose intolerance

Meat and fish
Fruit and vegetables
Potatoes, pasta, rice
Pulses and nuts
Cereals, cereal flakes
Herbs (be careful with spice mixtures)
Fruit juices, mineral water, tea and coffee
Lactose-free milk, e.g. “Lakto-Free” or “Minus L
Soy products: All milk products made from soya are suitable without restriction.

If it is not possible to avoid dairy products or if symptoms occur even with very small amounts of lactose, the missing enzyme lactase can be replaced in tablet form. The individual need must be determined by the patient. When taking the tablets, it should be noted that the respective preparation must be taken with every meal containing lactose.

Avoiding calcium deficiency

A consistent low-lactose diet can lead to an undersupply of calcium in the body. Therefore, depending on tolerance, low-lactose dairy products such as ripened cheese and yoghurt should continue to be consumed. Calcium-rich mineral waters and vegetables (broccoli, spinach, leek, kale, soybeans), but also nuts and seeds (hazelnut, pistachio, Brazil nuts, almonds) can be a source of calcium.