Parents may protect babies against future allergies by sucking on kids' pacifiers

To protect a baby against future allergies, parents may want to consider sucking on their kid's pacifier.

New research finds kids whose parents "cleaned" their child's pacifier by sucking it were less likely to develop asthma, eczema and food allergies when compared to kids whose parents opted to avoid the not-so-pleasant-sounding cleaning method.

"We demonstrate that a common parental practice, sucking on the infant's pacifier before it is given back to the infant, is associated with protection against early eczema development and asthma symptoms," wrote the researchers, led by Dr. Bill Hesselmar, a pediatric allergist at the University of Gothenburg in Sweden.

For the study, researchers enlisted a pool of 184 Swedish infants that weren't born prematurely. Eighty percent of the children had at least one parent who already had allergies.

Infants were tested for food and airborne allergies at ages 18 months and 3 years old. Parents kept detailed diaries of their child's upbringing for the first 12 months of their lives, including whether they developed illnesses or took medications. Parents were also interviewed beginning when their child was 6 months old, and two questions asked were: "Does the child use a pacifier?" and "Is it cleaned by boiling, rinsing in tap water, or by the parents sucking on it?"

Almost seventy-five percent of infants studied used a pacifier during the first six months of their lives. Most of the parents rinsed the pacifier in tap water, but approximately half of parents also boiled it and another 65 of them turned to mouth "cleaning" the pacifier.

Children whose parents sucked on pacifiers were about 88 percent less likely to have asthma and 63 percent less likely to have eczema and also were less likely to display sensitization to food allergens - an immune response indicative of allergies - at age 18 months than children whose parents did not engage in this practice. Protection against eczema remained statistically significant for infants in the pacifier-sucking group through the time they turned 3, the researchers found.

Boiling the pacifier was associated with a slight increase in asthma rates, but the researchers said it was not statistically significant and that finding may be due to chance.

Additional DNA tests revealed children whose parents cleaned the pacifier by sucking had different bacteria and germs in their mouths -- called "microbiota" -- than those whose parents did not suck on pacifiers. The researchers also observed a protective effect against asthma and eczema in children born vaginally as opposed to through a cesarean-section. The authors found both having a vaginal birth and sucking on a child's pacifier amounted to a 2.5-times reduced likelihood the child develops eczema.

The new research was published May 6 in Pediatrics.

The study ties into the so-called "hygiene hypothesis," a theory which states early exposure to germs and bacteria may strengthen a child's immune system, thereby reducing allergies later in life.