Researchers have finally learned why children who are exposed to a dog in the home in early infancy seem to have lower risks for developing allergies and asthma. Though many people would initially think that exposure to dogs isn’t good for a baby, but the changes that these pets cause within the community of microbes within the home makes the biggest difference.

How Does It Happen?

In short, when dogs are permitted indoors and outdoors, this changes the microbes that live within the environment. Studies indicate these changes, which occur within the gastrointestinal microbiome, work to reduce the reaction of the immune system on common types of allergies. The study was conducted by researchers from the Division of Gastroenterology at the UC San Francisco and the University of Michigan.

What studies have provided is not only how this happens, but also the reason it happens. Studies indicate that there are specific bacterial species in the gut that help to provide protection to the airways against the viral respiratory infections and allergens many people are exposed to.

What Does This Mean for Our Pet-Filled Homes?

In short, doctors have known for a long time that children who grow up in a home with a pet or live on a farm, are less likely to experience complications such as allergies and asthma. Previously, many doctors believed that the hygiene hypothesis was true, which states that many homes have simply gotten too “clean” for the immune system to become exposed to enough bacteria and viruses to build up immunities. With new study, though, provides some new light on why dogs seem to be linked to this improvement.

In short, the microbes that lived in the dust reshaped the community of living organisms living within mice (the initial study was conducted on mice.) The changes created helped the mice to fight off various types of allergen reactions. All of this comes from a single bacteria called Lactobacillu johnsonii, which is very common in areas where dogs live.

In many ways, then, dogs are helping to contribute to a healthier lifestyle for humans, even through the use of the bacteria living within their guts.