The Amish might be better known for beards and "barn-raising" than biomedical studies, but a new study has found a fascinating link between low asthma rates in Amish children and their house’s dust.
The research, published in The New England Journal of Medicine, suggests that the “Amish environment” can cause changes to children's immune systems and help protect them from developing asthma.
They compared Amish individuals with those from the Hutterite community, another group of traditionalist Christians who emigrated to the US from Central Europe in the 18th and 19th centuries. Both of these communities share a very similar genetic ancestry. Socially and culturally, they also have many similarities: They both shun modern technology such as television and computers, they both live in large extended families, and they both eat a similar “Germanic” diet including unpasteurized milk.
However, as Carole Ober, professor and chairman of human genetics at the University of Chicago, explains in a statement, they have a “whopping disparity in asthma” rates. Just 5 percent of Amish schoolchildren have asthma, one-fourth the rate of asthma in Hutterite children, and around half the US average.
To investigate this, genetic scientists from the University of Chicago began to look at blood samples from 30 Amish children and 30 Hutterite children.
"The Amish had more and younger neutrophils, blood cells crucial to fight infections, and fewer eosinophils, blood cells that promote allergic inflammation," study co-author Anne Sperling, associate professor of medicine at the University of Chicago, said in the statement.
The blood samples also found that Amish children showed signs of having enhanced activation of immunity genes.
So what could have caused this? One of the differences that separates the Amish and Hutterites is the way they farm. Hutterite communities tend to use farm machinery such as tractors, while the Amish still use horses for the majority of their work. This means that Amish households are constantly exposed to farm animals.
"Neither the Amish nor the Hutterites have dirty homes," Ober explains. "Both are tidy. The Amish barns, however, are much closer to their homes. Their children run in and out of them, often barefoot, all day long. There's no obvious dirt in the Amish homes, no lapse of cleanliness. It's just in the air, and in the dust."
Paired with this knowledge, the researchers then collected airborne dust samples from 10 homes in each community and looked at the microbial life living among them. Their analysis showed that the Amish dust was notably richer in microbial life.
They then tested this hypothesis by exposing mice to different types of dust. Those exposed to Amish dust were much less likely to get asthma than those exposed to Hutterite dust.
The researchers aren’t certain which microbes, whether it be fungal, bacterial, or a combination of the two, could be responsible for this effect. They hope to follow up the study by identifying the relevant substances in the dust in order to one day harness them in asthma prevention strategies or treatments.
"You can't put a cow in every family's house," Ober added, "but we may be able to protect children from asthma by finding a way to re-create the time-tested Amish experience."