Infants 'need' exposure to dirt
Friday November 4th, 2011
New-born babies need to encounter a wide range of bacteria to lessen their chances of developing allergic disease later in life, Danish research has concluded.
Professor
Hans Bisgaard, consultant at Gentofte Hospital and professor of children's
diseases at the Faculty of Health Sciences, University of Copenhagen,
said reduced diversity of intestinal microbiota in infancy was associated
with increased risk of allergic disease at school age.
But children with more diverse bacteria were at reduced risk of developing allergies.
“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,” he says.
“This may be why far more children born by caesarean section develop allergies.”
The Danish study, which examined 411 children whose mothers had asthma, found a direct link between the number of different bacteria in their bodies and the risk of development of allergic disease later in life, says Prof Bisgaard.
The mother’s immune system protects babies in the womb and in the first six months of life, but Prof Bisgaard says: “The window during which the infant is immunologically immature and can be influenced by bacteria is brief, and closes a few months after birth.
“We have studied staphylococci and coli bacteria thoroughly, and there is no relation. What matters is to encounter a large number of different bacteria early in life when the immune system is developing and 'learning'.”
The children who took part in the study were monitored, interviewed and tested continually from birth to aged 12.
“I think that a mechanism that affects the immune system will affect more than just allergies,” says Prof Bisgaard. “It would surprise me if diseases such as obesity and diabetes are not also laid down very early in life and depend on how our immune defences are primed by encountering the bacterial cultures surrounding us.”
Tags: Allergies & Asthma | Child Health | Childbirth and Pregnancy | Europe | Women’s Health & Gynaecology
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