Getting up close - and a little dirty - with farm animals just might help us fend off illness, say researchers who've further demonstrated the benefits of early exposure to a wide variety of environmental bacteria.
Scientists from The Ohio State University found that bacteria and other microbes from rural Amish babies was far more diverse - in a beneficial way - than what was found in urban babies' intestines. And, in a first-of-its-kind experiment, they found evidence of how a healthier gut microbiome might lead to more robust development of the respiratory immune system.
The study was published this month in the journal Frontiers in Immunology.
"Good hygiene is important, but from the perspective of our immune systems, a sanitized environment robs our immune systems of the opportunity to be educated by microbes. Too clean is not necessarily a good thing," said the study's co-lead author Zhongtang Yu, a professor of microbiology in Ohio State's Department of Animal Sciences and a member of the university's Food Innovation Center.
The research team collected fecal samples from 10 Ohio babies who were around 6 months to a year old. The five Amish babies all lived in rural homes with farm animals. The other five babies lived in or near Wooster, a midsize Ohio city, and had no known contact with livestock.
The samples revealed important differences - particularly a wide variation in microbes and an abundance of beneficial bacteria in the Amish babies' guts that wasn't found in their city-dwelling counterparts. The researchers expected this, based on the infants' exposure to the livestock and the fact that the Amish tend to live a relatively less-sanitized lifestyle than most other Americans.
"The priming of the early immune system is much different in Amish babies, compared to city dwellers," said Renukaradhya Gourapura, co-lead author of the study and a professor in Ohio State's College of Food, Agricultural and Environmental Sciences and Food Animal Health Research Program.
What they really wanted to know was how these differences might affect development of the immune system, setting the groundwork for a body's ability to identify and attack diseases and its resistance to allergies and other immune-system problems. Previous studies in the U.S. Amish population and to comparable populations throughout the world have drawn a clear connection between rural life and a decrease in allergies and asthma, Gourapura said.