Intestinal bacteria: biodiversity protects against asthma

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MunichThe more different types of bacteria cavort in the digestive tract, the better it is for the organism. This is confirmed once again by a Swedish study. Accordingly, a particularly large biodiversity in the intestine can apparently even protect infants from asthma.

The study by Thomas Abrahamsson and his team from Linköping University was based on stool samples from 47 children. The researchers examined the composition of the stool at different times, namely when the babies were one week, one month and twelve months old. The scientists then accompanied the children until they were seven years old. During this time, the state of health was recorded again and again. Among other things, allergy tests were also carried out.

First month crucial

At the end of the seven-year study period, 17 percent of the children had developed chronic asthma, 28 percent had hay fever and 26 percent had eczema on the skin. All of these are allergic diseases that are closely related to one another.

However, only in the development of asthma was a clear connection between the diversity of the intestinal inhabitants in the first few weeks of life to be seen. The fewer species the researchers found, the more likely the children would later suffer from the lung disease. How great the diversity of intestinal bacteria was after one year was not decisive.

Training camp for the immune system

"A high diversity of intestinal microbes during the first months of life seems to be important for the development of the immune system," concludes the pediatrician Abrahamsson. The thesis: In order to function properly, the child's immune defense must be trained - and this is best done in combat with many different opponents. The bacterial world in the intestine does not offer enough training options. In addition, the presence of many different germs seems to strengthen the barrier function of the mucous membranes.

"We assume that a deficit in the maturation of the immune system and a less efficient mucosal barrier clears the way for certain viral infections," said the researchers. These infections, in turn, could be linked to the development of asthma.

Colon colonization in infants

The diversity of the intestinal flora in infants depends on various factors. On the one hand, during a vaginal birth, the baby comes into contact with the mother's germs, which then also settle in his intestines. For example, a study last year showed that children born by caesarean section suffer more frequently from allergies due to a poorer intestinal flora composition. On the other hand, the diet has a great influence. For example, the intestinal flora can be used to determine whether the child is breastfeeding or bottle-fed. The application to the breast has a positive influence on the composition of the intestinal colonization. (lh)

Source: T Abrahamsson et al. Low good microbiota diversity in early infancy precedes asthma at school age; Clinical & Experimental Allergy, in print 2014. DOI: 10.1111 / cea.12253

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