Dogs may make us more caring and sociable by changing our microbiome

Dogs may be man's best friend, but what if they improve our well-being not only by being our furry companions, but by changing our lives? microbiome? A series of experiments on mice has shown that dog owners have a unique set of bacterial species that promote empathetic and social behavior.

We know that pets improve our satisfaction with life and play a role in shaping our gut microbiome. Research is also increasingly showing that this microbiome affects our mental health and even helps shape our personality. Dogs usually top popular pet lists. Takefumi Kikusui from Azabu University in Japan wanted to understand whether animals change our microbiome in ways that promote well-being.

To study this, the researchers analyzed surveys in which caregivers of 343 teenagers aged 12 to 14 living in Tokyo reported various aspects of their social behavior, such as how often they felt lonely, were cruel to others, or struggled to get along with their peers. Surveys also showed that about a third of teenagers owned a pet dog.

Researchers found that those who dogs were on average considered less socially withdrawn and behaved less aggressively than non-dog owners. The team also took into account other factors that may influence this behavior, such as gender and household income.

Saliva samples also showed that several species Streptococcus The bacteria were more common in teenagers living with dogs, which was associated with decreased depressive symptoms.

“If you play with your dog a lot, you will often be exposed to germs that the dog has from licking [and] they jump on you,” he says Gerard Clark at University College Cork in Dublin, Ireland. These bacteria can enter the gastrointestinal tract, where they can produce anti-inflammatory chemicals such as short-chain fatty acidswhich improve mental healthhe says.

In a crucial part of the study, the team transplanted oral microbes from three dog owners and three non-dog owners into the stomachs of germ-free mice. Based on stool samples, they were able to tell that the microbes had reached the mice's intestines.

Over the next few weeks, the team put the animals through a series of behavioral tests. In one case, mice were placed in a cage and another mouse was placed in a tube. The researchers observed that mice that received transplants from dog owners chewed the tube and poked their nose into the holes significantly more often than mice that received transplants from non-dog owners.

This suggests that the former mice were more sympathetic and tried to help, Kikusui says. We recently learned more about mouse care: research has shown that they help your pregnant companions with childbirth and even provide first aid.

In another test, transplant recipients who were dog owners sniffed an unfamiliar mouse in their cage more often than the other group, suggesting they were more social, Clark says. “This social behavior is relevant to all species, including humans,” he says. “Social media has a positive effect on mental health: if you don’t use social media much or if your social network is small, then it’s probably not good.”

“Knowing more about these microbial changes could one day benefit people who don't have dogs, for example if we can develop probiotics that mimic them,” Clark says. But research is needed in other geographic regions where microbial exposure may vary, he says.