Eight weeks after her first baby was born, still recovering from an emergency C-section, Heather Barnes did the unthinkable: she got a puppy. While pregnant, her beloved dog had died and she missed the companionship. So when she found a black Lab that was born on the same day as her daughter, Hazel, she had to bring him home. “I thought it was a sign,” recalls the Victoria-based mom of two. “I grew up with a dog and I wanted my kids to have that experience, too. It’s comforting to have a dog around.”
While Barnes was well aware of the emotional benefits of pet ownership, what she didn’t realize was that her puppy, Ivan, could also play a part in her kids’ long-term health.
A new study out of the University of Alberta shows that babies born into families with furry pets have a reduced risk of developing allergies and obesity if they’re exposed to the animals in the first few months of life. This is because the levels of two types of gut bacteria—Ruminococcus, which is associated with a lower risk of allergic disease, and Oscillospira, which is linked to leanness—are increased twofold when there’s a pet in house. Cats and dogs carry the healthy bacteria on their bodies, so cuddles and face licks could lead to the immune-boosting transfer.
The study looked at the gut microbial composition of 746 Canadian infants in the first three months of life. Before and after the babies were born, nearly half of the families had pets in the home (primarily dogs) and another eight percent had an animal only during the prenatal period. Even among families who just had a pet during pregnancy, there were still increases in the microbes that reduce the risk for obesity and allergies in babies, thanks to animal exposure through the womb. This bodes well for Hazel, who got a double-dose of doggie microbes from Ivan and his predecessor, Leroy. Now, nearly seven years old, Hazel has no allergies and is a healthy weight, as is her four-year-old sister, Frances.
Microbial colonization of the baby’s gut is an important process that impacts future health in ways we are just starting to understand. Anita Kozyrskyj, a University of Alberta paediatric epidemiologist and one of the authors of the study, explains that we are all born with some microbes acquired in the womb or through our journey down the birth canal. Those initial colonizers, or “pioneers,” as Kozyrskyj calls them, lay the foundation for the next sets of microbes that colonize the gut through environmental exposure. “Between one to three years of age, we develop our fingerprint of microbial colonization that stays with us for the rest of our lives,” Kozyrskyj says.
Because babies born by C-section miss out on healthy microbes from the birth canal, and as a result have higher rates of obesity, pets can be particularly helpful to them. A 2015 study published in the Maternal and Child Health Journal shows that babies born by C-section are twice as likely to be obese by the age of two, but having a pet was found to mitigate the risk. The University of Alberta study backs this up, showing that while women who have emergency C-sections have elevated of levels Enterobacteriaceae—associated with an increased risk of becoming overweight—having a pet present can decrease the bacteria’s prevalence.
The new study also shows that having an animal around the house can reduce the likelihood of mother-baby transmission of Group B streptococcus, a bacteria carried by 10 to 30 percent of women in North America. “Streptococcus increases the risk of the newborn developing pneumonia, which can be a very fatal infection,” Kozyrskyj says. “We think this is a very strong finding and exciting in terms of benefit to the newborn.”
This is all good news for Barnes, who brought Ivan home at just the right time. “Ivan is part of the family, and he’s here to stay,” she says, “so it’s great to hear he may offer some health benefits.”
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