High diversity and a variety of bacteria in the gut protect children against allergies as opposed to some individual bacterial genera. These are the findings of a comprehensive study of intestinal microflora (gut flora) in allergic and healthy children, which was conducted at Linköping University in Sweden.
One hypothesis is that our immune system encounters too few bacteria during childhood, which explains the increasing proportion of allergic children. However it has been difficult to substantiate the hypothesis scientifically.
"We conducted the study in collaboration with Karolinska Institute and the KTH Royal Institute of Technology which substantiates the so-called hygiene hypothesis. Children acquire intestinal microflora from their environment, and in our society they are probably exposed to insufficient bacteria that are necessary for the immune system to mature", says Thomas Abrahamsson, paediatric physician and a researcher at Linköping University.
Abrahamsson is the lead author of the study recently published in the esteemed Journal of Allergy and Clinical Immunology.
Researchers previously believed that diversity and variability -microbial diversity - is significant for allergy development in infants. However, not until now, can a clear connection be established due to the latest DNA-based technologies. Employing these cogent methods enables a complete overhaul of the microbiological framework.
Stool samples from 40 children were analysed: 20 children with atopic eczema and allergic IgE antibodies to foods, and another 20 in a control group that lacked these conditions. Using the so-called 454-pyrosequencing, the researchers identified DNA sequences that were then simultaneously linked with a database to determine which bacterial genera was present in the samples.