A diverse bacterial gutflora in infancy protects against allergy

Published Online: July 22, 2011

In an upcoming issue of The Journal of Allergy and Clinical Immunology (JACI), Bisgaard et al, report that high diversity of the intestinal bacteria during infancy protected against allergy at school age in the Danish birth cohort COPSAC (Copenhagen Prospective Study on Asthma in Childhood).

DNA-based technology identified a number of different bacteria in the gut during the first year of life. Diversity of bacteria in infancy was inversely associated with allergy and hay fever by age 6, but without association to asthma and eczema. The validity of the findings is strengthened by the prospective nature of this clinical study with close follow-up from birth to age 6 at a single research site.

The immune system is immature in the first months of life making this period particularly critical for immune priming. It has been speculated that lifestyle related diseases may be caused by an unfavorable bacterial milieu skewing the immune system in early life. This study supports the general hypothesis that an imbalance in the bacterial flora in early life is skewing the immune system towards allergic diseases.


The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

AAAAI - American Academy of Allergy Asthma & Immunology