It may seem counterintuitive, but parents who clean their baby’s pacifiers simply by popping it into their own mouths may be lowering their child’s risk of allergies.

According to new U.S. research being presented at the American College of Allergy, Asthma and Immunology (ACAAI), the children of mothers who sucked on their pacifiers in order to clean them had a lower allergic response than children whose mothers cleaned the soothers either by sterilization or hand washing.

The researchers interviewed 128 mothers of infants over the course of 18 months for the study.

“We found the children of mothers who sucked on the pacifier had lower IgE [immunoglubin E] levels,” Dr. Eliane Abou-Jaoude, the study’s lead author and a fellow at the Henry Ford Health System in Detroit, explained in a press release.

IgE is a type of antibody that is produced when the immune system overreacts to an allergen, which can then cause an allergic reaction. Higher IgE levels indicate a higher risk of having allergies and allergic asthma, according to Abou-Jaoude.

Of the 128 mothers participating in the research, 58 per cent reported that their child currently used a pacifier. Of that group, 41 per cent of respondents reported cleaning their child’s pacifier by sterilizing it, 72 per cent said they hand washed it, and 12 per cent said they sucked on it themselves.

Dr. Edward Zoratti, a co-author of the study and an allergist-immunologist at Henry Ford Health System, said the suppressed levels of IgE were evident in the babies at around 10 months of age until they were 18 months old.

“Further research is needed, but we believe the effect may be due to the transfer of health-promoting microbes from the parent’s mouth,” he said. “It is unclear whether the lower IgE production seen among these children continues into later years.”

Abou-Jaoude said the results of the study support a growing body of evidence that argues a certain amount of exposure to germs at an early age can lead to a healthier immune system.

“We know that exposure to certain microorganisms early in life stimulates development of the immune system and may protect against allergic diseases later,” she said.

The researchers stressed that their findings suggest only a possible association between parental sucking on pacifiers and reduced allergy risk and not a direct causation.

“Our study indicates an association between parents who suck on their child’s pacifier and children with lower IgE levels but does not necessarily mean that pacifier sucking causes lower IgE,” Abou-Jaoude said.