Having a Pet Early in Life May Lower Risk of Allergy, Obesity

A new study from the University of Alberta revealed that having household pets could help reduce the risk of allergic diseases and obesity among infants.

The study, published in the journal Microbiome, showed that early-life exposure to pets can alter the gut microbial composition of infants by exposing them to two types of microbes, making them less likely to develop childhood obesity and allergy.

"There's definitely a critical window of time when gut immunity and microbes co-develop, and when disruptions to the process result in changes to gut immunity," said Anita Kozyrskyj, a pediatric epidemiologist at the University of Alberta and lead author of the study, in a press release.

For the study, the researchers analyzed fecal samples collected from 746 infants registered at Canadian Healthy Infant Longitudinal Development Study (CHILD). The mothers of the infants were enrolled in the CHILD study during their pregnancy between 2009 and 2012. The researchers of the study asked the participating mothers to report if they have acquired any pets upon their recruitment, during the second and third trimester, and three months after giving birth.

Among the mothers included in the study, more than half have pets during their pregnancy and after giving birth. The researchers observed that infants born in household with pets have higher levels of Ruminococcus and Oscillospira. Ruminococcus has been linked with reduced childhood allergies, while Oscillospira has been associated with lower risk of obesity.

The researchers also found that the benefit of having a pet starts during pregnancy and goes on until the infant's first three months. Furthermore, exposure to pets during pregnancy could also lessen the risk of vaginal transmission of Streptococcaceae, which causes pneumonia in infants.

In theory, exposure to dirt and bacteria from the pet's fur or paws can created early immunity in infants. The results of the new study showed that the transfer of bacteria could occur directly (pet to infant) or indirectly (pet to mother to infant). Because of this, the healthy microbiome exchange could occur during pregnancy or three months after the infant was born.