Though there are no definitive explanations for why food allergy incidence increased over the last three decades, one known factor is environmental influences.
“We have found for the first time that higher population density corresponds with a greater likelihood of food allergies in children,” said researcher Ruchi Gupta, M.D., Northwestern University. “This shows that environment has an impact on developing food allergies.”
The study, done by Gupta and colleagues in 2012, analyzed food allergies in children by ZIP code, and yielded some interesting results:
“The big question is — what in the environment is triggering the allergies?” says Gupta. Though there is yet no answer to her question, there are data-based suppositions.
One theory for the lower incidence of allergy in rural settings has to do with bacteria. Children living in rural environments may have more exposure to certain bacteria associated with country living that protect against sensitivity to allergens. Another hypothesis suggests that contact with city pollutants might be responsible the greater urban allergy rates.
Though it may turn out a variety of environmental factors are at play, identifying just one or two could make a significant difference in allergy incidence. That would be most welcome since, according to a 2011 study by Gupta, one out of 13 children in the U.S., under age 18, has a potentially life-threatening food allergy.
“A better understanding of environmental factors will help us with prevention efforts,” says Gupta.