Bacteria train the immune system

"Mummy, what am I actually allergic to?" – nowadays, this is a natural question for children to ask. In contrast, 30 years ago, very few children knew what the word allergy even meant. According to the hygiene hypothesis, the dwindling bacteria in our environment are responsible for the increase in the number of allergy sufferers. During pregnancy and the first few months of life in particular, there are sensitive time windows in which bacteria are responsible for training the immune system. Scientists refer to these as "windows of opportunity".

Living on a farm has a protective function

Scientists have studied the influence of microbes on the human immune system in the model situation of a traditional farm. The scientists were able to show that the risk of developing allergies was lower for children living on the farm or those who had a great deal of contact with other children. The protective function became more effective the more often the children were on the farm or the longer they were there for. The timing also proved to be important: The time spent on the farm had the most impact before a child was born and during the first few years of life. In contrast, after the age of five, it had barely any effect. It is the phases of pregnancy and infancy that therefore offer the opportunity for early immune training.

Bringing the farm to the city

Doctors and scientists are currently considering how they can bring aspects of life on a farm to the city. Although raw cow's milk during infancy has the effect of training the immune system, the risk of serious infections is too high to be able to recommend raw milk.

Scientists have the vision of a pill containing all the bacteria on a farm that have a protective effect. But there is a long way to go before they achieve that. However, there are already drugs available which contain bacteria and influence the immune system. Preparations containing inactive bacteria (Pro-Symbioflor), the safety of which has been proven through over 55 years of use, can be taken in order to utilise the sensitive time windows for training the immune system during infancy.