After researchers learned that Swiss farm kids are much less prone to allergies than city kids, they took a look at Amish families in the U.S. the incidence of allergies was even less with them:
The study did not determine why the kids who grew up on farms were less likely to develop asthma and allergies, but other research has pointed to exposure to microbes and contact with cows, in particular, to partially explain the farm effect (see Reuters Health story of May 2, 2012).
Drinking raw cow’s milk also seems to be involved, Holbreich said.
The going theory is this early exposure to the diverse potential allergens and pathogens on a farm trains the immune system to recognize them, but not overreact to the harmless ones.
As for why the Amish kids have even lower allergy and asthma rates than the other farming kids, “that piece of the puzzle we really haven’t explained,” Holbreich told Reuters Health.
He speculated that it could be at least partly a result of the Amish having larger families or spending even more time outside or in barns than people on more modern working farms.
Dr. Corinna Bowser, an allergist in Cherry Hill, New Jersey, said there’s also a possibility that inherited factors could play a role.