The idea that regular exposure to dirt, grime and the great outdoors in general is very healthy for kids is nothing new, but now a new National Institutes of Health (NIH) funded study goes one step further, touting the benefits of allergens and bacteria exposure. The study, led by Susan V. Lynch, PhD, and Robert A. Wood, MD, FAAAAI, examined inner-city children in Baltimore, Boston, New York and St. Louis, and found that kids with the highest exposure to allergens and bacteria during their first year of life had a smaller chance of later developing allergies and asthma. Children in the study who were frequently exposed to allergens and bacteria had fewer instances of recurrent wheeze and allergic sensitization, important precursors to asthma and allergies. The researchers note that yes, it’s true that allergen-rich or bacteria-rich environments usually equal higher overall allergy and asthma rates for kids, but timing can be key. The researchers say, if children experience allergen-rich or bacteria-rich environments BEFORE their first birthday, they may actually benefit from it. “The immune system develops very rapidly in the first months of life so it makes sense that the timing of exposures early in life could be the most important,” Wood said.
Other findings in the new NIH report show that babies growing up in homes with a greater variety of bacteria or mouse, cockroach or cat dander in the first year of life showed lower rates of wheezing at age 3. Oddly, the more allergens and bacteria the better — as researchers also found that tots exposed to all three allergens PLUS high levels of bacteria experienced the most benefits. Wood explained, “We do feel that these results, especially those related to certain microbial exposures, do support the hygiene hypothesis. This is important since it has been said that the high rates of asthma and allergy in children living in inner-cities presented an exception to the hygiene hypothesis.” Now, the study isn’t saying that you should quit washing your child’s hands or let mold run rampant, but maybe chill out when it comes to your child getting messy outside and don’t freak about germs – as a kid who is TOO clean may have a higher risk of allergies and asthma. The researchers hope that the idea of regular exposure to high levels of certain allergens and bacteria as beneficial during the first year of a child’s life will possibly prompt new preventative strategies for wheezing and allergic diseases. This study will soon appear in The Journal of Allergy and Clinical Immunology. In the meantime, you can learn more about allergies, asthma and the hygiene hypothesis at the American Academy of Allergy, Asthma & Immunology (AAAAI) website.