Parents who suck on their child's dummy to clean it could be passing them health benefits, new research claims.
Researchers said the unusual habit may result in the transfer of healthy micro-organisms to children.
The scientists said they found those children to have lower levels of Immunoglobulin E (IgE), an antibody related to allergic responses in the body.
High IgE levels typically indicate a greater risk of having allergies and allergic asthma, lead author Eliane Abou-Jaoude said.
The study, by Henry Ford Health System in Detroit, involved interviews with 128 mothers.
Of the 58 per cent who reported their child currently using a dummy, 12 per cent said the parents sucked the pacifier to clean it.
Co-author Edward Zoratti said: "We found that parental pacifier sucking was linked to suppressed IgE levels beginning around 10 months, and continued through 18 months.
"Further research is needed, but we believe the effect may be due to the transfer of health-promoting microbes from the parent's mouth.
"It is unclear whether the lower IgE production seen among these children continues into later years."
Dr Abou-Jaoude said that while it indicated an association between parental pacifier sucking and children with lower IgE levels, it does not necessarily mean the practice itself causes the lower levels.
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