Your childhood pet may still be protecting you from stress as an adult — and science explains how
People who grew up around pets have fond memories from their childhood, but researchers claim that it also imparts a biological advantage. A new study has found that people with childhood pets handle stress differently than those who did not grow up with furry pals. Professor Christopher Lowry from the University of Colorado Boulder and an international team of researchers have worked to establish that the impact of handling stress better is relevant even after decades.
Prof. Lowry teamed up with John Sterrett, a CU Boulder PhD student, and published a study in the journal Brain, Behavior, and Immunity. He explained that people with regular contact with pets early in life develop protection against harmful immune responses to stress. Lowry stated in an official CU statement published on August 12, 2025, “Being raised in a home with pets can provide protection against chronic low-grade inflammation, which we know is a risk factor for stress-related psychiatric disorders and more.” Generally, people living in urban settings showcase more chronic stress than those in rural areas. This is because of how soil microbes influence our moods.
Mycobacterium vaccae (M. vaccae) is one of those good microbes that positively affect our body and brain. Now dubbed as “Old Friends,” considering their long history of co-evolution alongside humans, an experiment with mice revealed that the microorganisms produced antidepressant-like behavioral effects in mice. The Trier Social Stress Test was held to assess whether urban people who lived with pets also showed similar protection from inappropriate inflammation. When both pet owners and pet-free peers were assessed based on their immune function and inflammation taken before a stressful event like public speaking, the researchers found that individuals with pets had a more balanced immune response and regulation of stress-reactive cells.
“Exposures to ‘Old Friends,’ which are thought to increase in homes with pets, interact [sic] with our immune system to produce more regulatory T cells,” Lowry added. While it all seems sorted in theory, bringing the findings to reality to improve the mental health of people dealing with perceived stress was a challenge. That was until a CU Boulder startup company called Kioga began developing soil-derived microbiome-based nutritional supplements to help anyone with high levels of stress. While the major debate remains between rural and urban lifestyles, a simple solution would be to adopt a pet and spend quality time with it. A worthy stress-buster, no doubt. More so, the impact of a robust immune system is functional even after decades of owning a pet.
The focus, however, remains on the significance of soil microbes and how they influence the natural environment and the human body. Although the study has its own set of limitations, as it mainly assessed healthy adult men raised in cities either with or without pets. Women did not participate in the study, so it does not confirm whether they would have a similar immune response to that of their male counterparts. “More work is needed to fully understand the importance of upbringing in rural versus urban lifestyles in females,” Dr. Lowry emphasized in the study.