Infants exposed to bacteria may be less prone to asthma and allergies in early childhood, according to a new study.
Contaminants in home air supply a wide range of bacteria varieties that help babies develop natural defenses to disease. Not only do bacteria in the air help babies stay healthier through childhood, but those exposed to significant levels of allergens were least likely to suffer from allergies.
Susan Lynch of the University of California led a study of these childhood ailments and their link to exposure in early life. Researchers from several institutions took part in the study. Investigation was focused on understanding why children from poor inner cities suffer asthma more frequently, and severely, than other youngsters.
"Early-life allergies and wheezing illnesses are the two main risk factors for childhood asthma," James Gern of the Wisconsin School of Medicine and Public Health, and co-author of the study, said.
Lynch and her team analyzed the concentration of allergens in homes, including those from cats, cockroaches, mice and dust mites. Allergens commonly carried by dogs were exempted from the study. This information was compared to incidents of wheezing, reported by parents, and results of allergen tests, conducted with skin pricks.
Some of the bacteria that help protect human children come from unlikely sources - cockroaches and mice, the team found.
The human gut is home to a pair of types of bacteria the researchers found were highly-effective at preventing asthma. Bacteriodes and Firmicutes were discovered to be protecting 104 inner-city children in the study from the condition.
Lynch's team discovered exposure to allergens and bacteria in the first year of life helped protect infants. However, exposure in later life increased incidences of wheezing and allergies.
The mechanism by which bacteria in the environment help protect babies is uncertain. However, earlier research suggests exposure could help strengthen the immune system of infants.
"These findings suggest that concomitant exposure to high levels of certain allergens and bacteria in early life might be beneficial and suggest new preventive strategies for wheezing and allergic diseases," researchers wrote in an article announcing their study.
One day, instead of keeping babies away from bacteria and allergens, doctors may use the pollutants to help prevent health problems.
Lynch believes this could involve "microbial supplementation to inoculate children in early life with appropriate microbes to help protect them against wheezing and allergy," according to a university press release.
Investigation of the role played by bacteria on infant health was profiled in the Journal of Allergy and Clinical Immunology.