Parent’s saliva cleans pacifiers, deters allergies

Moms and dads who clean their babies’ pacifiers by sucking on them may be boosting their infants’ immune systems by passing along oral microbes that help deter allergy development.

A new study has found that a parent’s saliva introduces gut microflora onto the pacifier that in turn stimulates an infant’s immune system against allergies, eczema, and asthma. Oral bacteria are transferred on the pacifier from the parent’s mouth to the baby’s mouth and swallowed, which subsequently affects the microbiota in the child’s small intestine and regulates tolerance development in the gut.

Among 136 babies who used a pacifier during their first 6 months of life, 65 had parents who reported sucking on the pacifiers to clean them. When the children were aged 18 months, researchers found that the likelihood of both eczema and asthma were reduced in the children whose parents had used saliva to clean the pacifiers when compared with children whose parents did not clean the pacifiers this way. The protective effect held for eczema through age 36 months.

The study also found that spit-cleaning the pacifiers had no effect on transmission of respiratory illnesses from parents to children.

Researchers said that parents could choose instead to clean their baby’s pacifier with soap and water or by boiling it; however, they recommend that parents lick the pacifier if their child was born through cesarean delivery. These children are more likely to develop allergies because they do not receive the immune system-boosting gut microbes that babies born vaginally receive when they pass through the birth canal.