Doctoral student Kim Kelly, pictured with her cocker spaniel Katie, is one of the primary investigators in the UA’s study.

Yaron Yarden / Courtesy Kim Kelly

Greek yogurt and kimchee may enhance digestion and gut health, but a canine roommate could be even better.

“Dogs as Probiotics” is a University of Arizona study that aims to give researchers clues about which microbes in the human and canine gut play important roles in mental and physical health, as well as cognitive functioning.

“This has the potential to change the field in terms of how we understand, think about and use microbes to improve our health,” said Kim Kelly, a UA doctoral student in medical anthropology, and one of the study’s primary investigators.

“We already know that dogs make us happier and in some ways healthier. The main point of this study is to try and understand whether or not there is an actual biological component behind this,” she said.

The study team is currently recruiting adults over the age of 50 and asking them foster a dog from the Humane Society of Southern Arizona for three months. Participants will have the option of adopting the dog at the end of the study period.

Both human and canine subjects will undergo non-invasive tests during that time. The objective is to determine whether or not the positive microbes in the humans increase over the time they are living with dogs and whether it correlates with improved immune measures in older adults.

The study originated with Dr. Charles Raison, a UA psychiatrist who studies novel treatments for mood disorders. Kelly began working for Raison in 2012 to help pay her way through school. They then discovered a shared research interest in the animal-human bond.

“We began looking into this issue of animals and our shared microbiota and found there was a great wealth of interest in it around the UA as well as outside,” Kelly said.

At the same time, husband and wife researchers Dieter and Netzin Steklis began something called the Human-Animal Interaction Research Initiative (HAIRI), which aims to bring together researchers across disciplines to explore human-animal relationships for health and well-being.

HAIRI’s other projects include studying animal-assisted therapy for autism. Another project will test the common assumption that if you are caring toward animals then you are also caring toward humans, and vice versa.

In addition to Dieter and Netzin Steklis, Raison and Kelly, the dog health study collaborators include researchers from the University of Colorado at Boulder.

At the beginning of the study, researchers will do evaluations of the human participants’ gut bacteria, diet, physical activity levels and immune function. The dogs’ gut bacteria and physical activity levels also will be measured via non-invasive means.

Follow-up evaluations will take place after one, two and three months to look for any positive impacts on gut microflora in either the humans or the dogs. Researchers also will note any changes in the mental health and emotional well-being in both the humans and the animals.

Should results from the study suggest that canine companionship is beneficial to the microbiota of older human companions, the research team plans to implement a larger, full-scale clinical trial.

Kelly says her own Humane Society of Southern Arizona (HSSA) rescue dog — a 7-year-old named Katie — provided inspiration for her research.

“I’ve lived with dogs my entire life — my parents had a border collie mix when I was born and I’ve never had any illnesses other than the common cold,” Kelly said.

“So I would say my connection with all the dogs I’ve shared my life with has sparked an interest in this research, and I hope that positive findings from this and future research will encourage more people to adopt from rescues such as the HSSA in the future.”