Babies who have dummies (known as pacifiers in the US) have an unfortunate habit of dropping them. They also demonstrate a distinct lack of patience if their dummy is not returned to them promptly. This can present a problem because, naturally, most parents or guardians who see a dropped dummy will want to clean it before giving it back to their child. The preferred method for many parents, time permitting, is to use boiled water, or at the very least tap water. However, many of us have been guilty of picking up the dropped dummy, popping it in our own mouth to ‘clean’ it and then giving it back to our child. Time saving? Yes. Hygienic? Possibly not. Beneficial to our child’s immune system? Surprisingly, yes!
 
Those babies who were exposed to their parents’ oral microbiota seemed to be protected from allergy development. Specifically their risk of developing asthma or eczema by 18 months of age was reduced. The ‘hygiene hypothesis’ suggests that young children who are not exposed to microbes early on have a greater chance of developing allergies. The oral cavity is rich in microbes and, by using their mouth to clean a dropped dummy, parents are inadvertently transferring their own oral microbes to their child. This helps to mature the child’s immune system even before they start eating solids.
 
The protective effect was enhanced in those children who were born vaginally, rather than via caesarean (C-section). Parents in the former category were, in fact, more likely to use their mouth to clean their child’s dummy, than those who had undergone a C-section. Children who were born vaginally and whose parents had this habit, had a 20% chance of developing eczema; in contrast, children born via C-section, whose parents did not use their mouths to clean the dummy, had a 54% chance. There is, therefore, the suggestion that those children born via C-section who are inherently more at risk of developing allergies, may reduce their risk by increasing their exposure to their parents microbes.
 
Taking other simple steps can also help boost your child’s immune system from a young age; these include, spending time outdoors, having regular contact with animals and pets and mixing with friends and family. This will all help with the build-up of healthy bacteria in the mouth and the gut. It is important, however, to also maintain good, basic hygiene and encourage regular hand washing.
 
Sources:

• Hesselmar, B, et al. “Pacifier Cleaning Practices and Risk of Allergy Development.” Pediatrics, vol. 131, no. 6, June 2013, pp. e1829–1837., doi:10.1542/peds.2012-3345.