Can Early Exposure to Bacteria Lower Allergy Risk?
Children who are exposed to a wide range of bacteria as infants are less at risk of developing allergies, says a new study by Danish researchers. Ironically, something that has long been considered a threat to public health — bacteria –could actually be a “fundamental part of a healthy life.”
Today, 25 percent of the population of Denmark suffers from allergies, or oversensitivity diseases. Professor Hans Bisgaard, professor of children’s diseases at the Faculty of Health Sciences, University of Copenhagen, and other researchers studied 411 children whose mothers have asthma. The children were monitored, interviewed and tested continually from birth on. Researchers found a connection between intestinal bacteria and the child’s risk of developing allergies later in life:
Reduced diversity of the intestinal microbiota during infancy was associated with increased risk of allergic disease at school age. But if there was considerable diversity, the risk was reduced, and the greater the variation, the lower the risk.
Researchers considered a child’s exposure to bacteria in the womb, in the birth process and in the first six months of life, says Bisgaard:
“So it makes a difference if the baby is born vaginally, encountering the first bacteria from its mother’s rectum, or by caesarean section, which exposes the new-born baby to a completely different, reduced variety of bacteria. This may be why far more children born by caesarean section develop allergies.”
Early in life, the immune system is still developing and “learning.” At this time, there’s a brief “window” when an infant’s system is “immunologically immature,” when it can be influenced by bacteria. Children who were missed that “window” and whose intestinal bacteria were therefore less diverse are at greater risk for “allergic sensitization, allergic rhinitis, and peripheral blood eosinophilia, but not asthma or atopic dermatitis, in the first 6 years of life.”
That is, researchers suggest that “protecting” an infant from exposure to a broad range of bacteria is potentially more harmful, as doing so increases a child’s risk of allergies. The Danish study certainly offers food for thought in this day and age when so much effort is taken to prevent young children from coming into contact with those dreaded things, germs, whether on shopping cart seats or any sort of public space; when anti-bacterial products of all sorts are touted for their keeping your child “safe.” Could it be that, in our efforts to keep our little ones healthy, we may be losing out on a chance to help them build up valuable immunities to future allergies?
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