Good sweet, but not acceptable for everyone: the lactose

Whether mother's milk - or milk from cow, goat, sheep or mare: The milk sugar (lactose) is always responsible for the slightly sweet taste of the white juice. In addition, lactose is an easily digestible carbohydrate and provides a good source of usable energy.

But worldwide, most people cannot digest this valuable sugar after infancy. The cause of lactose intolerance is the deficiency or lack of the enzyme lactase, which has the function of a "lactose splitter" in the small intestine. If the cleavage persists, lactose cannot be digested and leads to stomach pain, flatulence, cramps and diarrhoea. Almost all Africans and Asians live with this missing enzyme, in Europe only 3-10% of the population.

Historically, lactase deficiency is the "normal" condition after infancy. In the course of evolution, the enzyme lactase has been preserved as a genetic defect, so to speak, for all the populations who kept dairy cattle and introduced milk as a foodstuff. This is also the case with us, where lactase deficiency is therefore regarded as a disease.

But why does nature produce this elaborate, exclusive luxury sugar in the milk, which is only digestible for infants or nursing young animals? Possibly in order to secure the food source for the needy newborns, because as long as the older siblings or adults do not tolerate the lactose, no "food cuttings" can arise on the coveted milk.


Lactose is used in many biscuits and bakery products for sweetening and must be declared on the ingredients list.

In well acidified dairy products and cheese, lactose is converted into lactic acid.

Written by Brigitte Neumann