The bacteria that colonize our digestive system right after birth are extremely important for the proper development of immunity. Disruptions in this process may translate into the appearance of various types of diseases later in life. As it turns out, colonization time is a particularly important factor, as proven by the latest research by scientists from the University of Copenhagen. Its delay is associated with an increased risk of atopic dermatitis.

The course of the study

Two groups of mice bred in sterile conditions, created especially for this type of experiment, took part in the experiment. The animals included in the first group received a cocktail of bacteria immediately after birth, targeted to colonize the large intestine. The mice in the second group received the same bacteria after a week of being kept in the sterile space.


As a result of the experiment, it turned out that the mice that received the bacteria a week later were not able to properly develop their immune system. Each group received the same bacteria, which made it easier to exclude the possibility of the influence of various types of microorganisms on the development of immunity of the subjects under study. As a consequence, mice in the second group, in which the process of colonization of the digestive system was delayed, were more likely to develop atopic dermatitis.

What is the window of opportunity – conclusions from the study

The experiment carried out by Copenhagen scientists confirmed the existence of a temporary window of opportunity. This term describes the period beginning immediately after birth during which the proper development of the microbiota is essential for the optimal functioning of the immune system in the future. The task of the microorganisms accumulating in the large intestine in the first moments of life is to protect the body against the subsequent occurrence of atopic reactions.

Most likely, the duration that the window of opportunity is open varies between mice and humans. Therefore, people may have more time to develop their immunity. It is worth emphasizing, how important the role of the gut microbiota is in controlling the internal processes and reducing the risk of serious diseases of various origins, including atopic allergic diseases.

The causes of atopic diseases are still unknown. Nevertheless, a study by scientists from Copenhagen and other similar experiments shed more and more light on the aetiology of these cases.