New research shows parents who suck their baby’s pacifier to clean it may be passing healthy microbes that boost their child’s developing immune system.

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Health-promoting microbes passed from parents to their children may be one way to reduce allergy risks in the future. Getty Images

Most new moms are willing to do just about anything to keep their babies healthy and safe.

They stock up on hand sanitizer, ban visitors with even the slightest sniffles, and generally go on a warpath against germs and potential contaminants.

So it’s not surprising that plenty of moms would find the idea of cleaning a pacifier with their mouths before handing it back to their baby repulsive — but it turns out that doing just that may actually be good for your little one.

Recent research presented at the American College of Allergy, Asthma and Immunology (ACAAI) Annual Scientific Meeting points to a potential link between the swapping of pacifier spit and a reduction in future allergies.

Over the course of 18 months, 128 mothers of infants were interviewed and asked how they cleaned their children’s pacifiers. The study results found that the children of mothers who sucked the pacifier clean presented with lower levels of lgE, an antibody associated with allergic responses.

The study’s authors acknowledged the need for more research, but proposed the theory that the observed reduced allergic responses may have been the result of “health-promoting microbes” transferred from the parent’s mouth to the pacifier and then on to the baby.

However, this research is new and may still need to be taken with a grain of salt.

Dr. Andrew Bernstein, clinical assistant professor of pediatrics at Northwestern University Feinberg School of Medicine pointed out the relatively small number of participants in the study and the short study timeline.

While the concept shows some promise, it needs more research.

He then told Healthline, “In contrast, there are concerns that when parents suck on their baby’s pacifiers, it may transfer the bacteria that cause cavities, leading to earlier tooth decay.”

A statement from the American Dental Association in 2013 backs up that concern, claiming that licking a pacifier “can potentially transfer cavity-causing bacteria from the parent to baby which may increase the baby’s chance of developing tooth decay as they grow.”

So the jury may still be out on whether or not pacifier licking causes more harm or good. But in the meantime, it’s not the only surprising way to potentially boost a child’s immune system and suppress allergic response.

A 2016 study published in Pediatrics found that children who suck their thumbs and bite their nails are less likely to develop allergies.

Frequent contact with livestock has been associated with protective effects as well.

Having pets has also been found to potentially reduce allergic response. And early exposure to roach allergens and rodent dander (yes, you read that right), as well as other household bacteria, also appears to reduce allergies, wheezing, and asthma.

In other words, breaking down the bubbles we may be otherwise inclined to keep our children in might actually help them to be healthier in the long run.

Bernstein acknowledged there are some things parents do with the intention of keeping their children healthy that may actually be achieving the opposite effect.

“There are concerns that washing hands too much and keeping children too protected from bacteria and viruses can lead to increased allergies,” he explained.

He went on to talk about how fruit juice can also have the appearance of being healthy, but is actually “mostly just sugar water with very little nutritional value.”

He also pointed out that while some parents may fear vaccines are in some way hurting their children, the fact is that “vaccines are an extremely safe way to teach the immune system to protect the body against potentially deadly bacteria and viruses.”

Bernstein told Healthline that a child’s immune system is built to get stronger with exposure to different agents, so allowing them to live outside that bubble can be a good thing.

Still, he’s not suggesting parents should send their newborns out into the world unprotected with the goal of building a stronger immune system.

“Newborns under the age of 2 or 3 months are extremely susceptible to serious illness because they have undeveloped immune systems,” he explained. “Infants in this age range who show any signs of illness need to be evaluated right away to determine if they have a serious illness brewing.”

He suggests parents wait to start bringing their newborns out into the world and around more people until after they have received their first round of immunizations, typically around 2 months of age.

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“Allowing children to get messy and play outside allows them to develop their immunity in natural ways,” said Dr. Andrew Bernstein. Getty Images

Registered dietitian Tiffany DeWitt, who works in Pediatric Nutrition Science at Abbott Nutrition, had her own advice for how parents can help their newborns build stronger immune systems.

“A child’s immune system develops over time, through a myriad of factors. As parents, we’re always looking for ways to help our children get the best possible start in life, and the number one way to support your baby’s immune system is by breastfeeding,” she told Healthline.

She explained that breast milk is the gold standard for infant nutrition, “with a perfect blend of components that support a baby’s immune system.”

And she talked about the research, which tells us that one of the factors behind breast milk’s immune system-boosting properties is human milk oligosaccharides (HMOs).

As children get older and move beyond the breastfeeding stage, DeWitt explained there are still ways to help boost their immune systems.

“Don’t forget about the power of leading by example,” she explained. “Fill your plate with colorful, whole foods like oranges and broccoli, which are both sources of vitamin C. According to a study in the journal Gut, even exercise may diversify your child’s gut microbes. So, try to make time to be active as a family.”

“While the first years of life are a critical time for developing the immune system, parents continue to play an important role in laying the foundation for a lifetime of good health for their child,” she added.

Bernstein had additional advice for parents looking to boost their children’s immune systems.

He suggests parents get their children their immunizations on time, as recommended by the AAP and CDC.

“Immunizations allow the body to safely develop protection against harmful diseases. In addition, allowing children to get messy and play outside allows them to develop their immunity in natural ways,” he said.

For children with compromised immune systems, however, he suggests extra caution.

“Live-virus vaccines can in some situations be dangerous to those with weakened immune systems, so vaccines should only be administered by physicians and nurses with experience in taking care of children with compromised immune systems.”

He explained those same children shouldn’t be around other children with illnesses, as they’re more susceptible to getting those illnesses themselves.

However, he added, “Playing and getting messy are still okay.”

At the end of the day, all parents have to make decisions about when and how to allow their children outside the protective bubble in which they instinctually want to keep them.

For some, that may mean licking the pacifier and popping it back in their baby’s mouth, or turning the other way when a little booger-picking or nail-biting commences.

For others it may simply mean allowing them to play at the playground without sanitizing their hands every 30 seconds.

Whichever path you choose, just know that a little exposure to the real world can be a good thing — as well as regular immunizations and breastfeeding, when possible.