Want a healthy baby? You may want to roll her around in dirt.
For decades, parents have shielded infants from bacteria and other possible triggers for illness, allergies and asthma.
But a surprising new study suggests that exposure to cat dander, a wide variety of household bacteria — and even rodent and roach allergens — may help protect infants against future allergies and wheezing.
Interestingly, contact with bacteria and dander after age 1 was not protective — it actually increased the risk.
“It was the opposite of what we expected,” said Dr. Robert Wood, chief of the division of allergy and immunology at the Johns Hopkins Children’s Center and co-author of the study in the Journal of Allergy and Clinical Immunology. “We’re not promoting bringing rodents and cockroaches into the home, but this data does suggest that being too clean may not be good.”
The new findings may help explain some contradictions in research on the so-called hygiene hypothesis, which suggested that kids growing up in a super clean environment were more likely to develop allergies.
“This doesn’t completely resolve the controversy, but it does add a big piece of the puzzle,” said Dr. Jonathan Spergel, a professor of pediatrics and chief of allergy at the Children’s Hospital of Philadelphia. . .
The hygiene hypothesis was developed after researchers noticed that farm kids were less likely to have allergies. Dirty environments, experts suggested, might be protective. The hypothesis seemed to explain why developed countries had skyrocketing rates of allergies and asthma. . .