Letting the family dog poop all over your child’s face may not seem healthy, but research suggests that it may provide an extra layer of protection against your child’s Crohn’s disease.
An unpublished study presented at Gastroenterology Week in San Diego in May added to the “hygiene hypothesis” — the idea that exposure to germs when a child was a child helps build a stronger immune system. Study researchers found that children who grew up with a dog or in large families were less likely to develop Crohn’s disease.
To conduct the study, which began in 2008 and is still ongoing, the researchers used questionnaires to collect information from more than 4,200 parents, siblings, or children with Crohn’s disease. This high-risk group participated in the Crohn’s and Colitis Canada Genetic, Environmental and Microbial Project, or GEM project. After 5.6 years, 86 study participants developed Crohn’s disease. The team then looked at environmental factors – family size, whether participants grew up on a farm, drank well or municipal water, drank raw or pasteurized milk, number of bathrooms in the house, and whether they lived with domestic pets (dogs and pets ). cat).
“We really want to get a clearer picture of the environmental factors that either protect against or contribute to Crohn’s disease,” says Williams Turpin, senior author of the study and a research associate at Mount Sinai Hospital and the University of Toronto. “This way we hope to develop interventions to reduce risk in the population.”
Turpin and colleagues focused on the family size and pet ownership of the study participants.
They test bowel function with urine tests that measure how much sugar passes through the colon. They found that exposure to dogs at any age was associated with better bowel function. For people who had a dog between the ages of 5 and 15, the odds of developing Crohn’s were reduced by 40 percent.
But owning a cat had no effect. Those who currently own a bird have a slightly increased risk of developing Crohn’s disease. But the people in the study didn’t have enough birds to say there was a clear association.
“One theory is that the way we interact with dogs is different from other animals,” says Dr. Turpin. “When dogs lick a child’s face, they are exposed early to the germs that the body learns to recognize, so there is no aggressive immune response when they encounter these germs later in life.”
This statement is consistent with previous research, including a baseline study in Sciences which found that early exposure to germs was associated with prevention of inflammatory bowel disease and asthma. In addition, a letter was published in 2021 in Frontiers in Immunology She noted strong evidence from around the world that growing up around farm animals was linked to fewer cases of asthma — a modified immune condition that’s also linked to inflammation, just like Crohn’s disease.
It can help grow into a large family
The research team also noted that living in a household of three or more people as an infant was also associated with a 59 percent lower risk of Crohn’s disease. Turpin says that people born into a larger family seem to develop more microbial diversity later in life, which is usually considered a sign of a healthy gut microbiome later in life.
While there is no conclusive evidence as to why this is, says Turpin, “It is tempting to speculate that it may be associated with increased exposure to microbes early in life. In fact, increased exposure to environmental microbes, particularly early in life, is thought to enhance immune tolerance later in life, and prevents an exaggerated inflammatory response to those microbes later in life.”
While the study revealed that living with dogs lowers the chances of developing Crohn’s disease, it did not show that people who had dogs had more bacterial diversity or a superior composition of bacteria in their gut.
“This part is very interesting because it suggests that environmental factors do not shape our microbes, but potentially influence how aggressively certain microbes may trigger a pro-inflammatory or anti-inflammatory response,” says Allen Sharpati Bishvayan, MD, A gastroenterologist and clinical director of inflammatory bowel diseases at Johns Hopkins Sibley Memorial Hospital in Washington, D.C., who was not involved in the study.
“A study like this is very thought-provoking and could show us some associations that merit further examination,” adds Rabia de Latour, MD, a gastroenterologist and assistant professor of medicine at NYU Langone Health in New York City. participate in the study. “The hope is that other researchers will see this, get a spark for an idea, and do the research that will fill in the missing pieces.” With more evidence, there is a better chance of finding ways to protect individuals from developing Crohn’s disease later in life.
Meanwhile, said Dr. Both Pishvaian and De Latour recommend letting kids play outside and getting a little dirty, and reducing the use of antibiotics to help them develop a healthy gut microbiome and a stronger immune system.
“I always tell new parents to practice reasonable hygiene, but don’t stress them out when their child puts her dirty hands in their mouth,” says Beshvayan. “The more your child is exposed to it, the better for his or her developing system. It is great that one of the best ways to develop a healthy gut is to just allow a child to become a kid.”
