How to Protect Children from Developing Allergies: A HealthCentral Explainer

ATsai Editor
  • Studies in the past several years have shed light on why some children develop allergies, and much of it has to do with exposure to certain bacteria or allergens at a young age. Here is some of the more recent research on how you might be able to help your child avoid allergies as they get older.


    Parents’ saliva on baby’s pacifier can ward off allergies

    A recent study published in the journal Pediatrics concluded that parents who cleaned their child’s pacifier by sucking on it themselves reduced their infant’s risk of developing allergies. Specifically, they found that those infants were less likely to develop asthma and eczema.

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    Researchers looked at 184 infants and examined them for allergy and sensitization to food and airborne allergens when they were 18 months old. They also gathered data on parental pacifier cleaning practices. Infant saliva samples were also collected at four months. They found that the saliva microbiota of infants whose parents had sucked their pacifier was different from that found in the saliva of other babies. They hypothesize that the reduced risk of allergies is due to immune stimulation from the microbes transferred from the parent’s saliva on the pacifier. This study builds on the hygiene hypothesis, which states that the more microbes children are exposed to at an early age, the better their immune system will develop, which can prevent allergies.


    Although the hygiene hypothesis has been supported in other research, Dr. James Thompson, a Board-Certified Allergist and Asthma Specialist and our resident Allergy and Asthma expert, says he has some concerns with parents cleaning pacifiers with their own saliva.


    “First there are some viral and bacterial infectious diseases we would not want to expose our young children to. Cold sores are teaming with infectious herpetic viruses and may be transmitted to the child possibly causing them to have life-long recurrent oral and facial cold sores.”


    In addition, Dr. Thompson says flu viruses can be transmitted through the pacifier, which can be devastating to an infant because their immune system is not fully developed. Overall, he says doctors have concerns about converting to an unclean lifestyle, because the risk can outweigh the benefits.


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    C-sections can promote allergies

    Another way to protect your child from developing allergies is avoiding a C-section in favor of a natural birth, according to a February 2013 study. Researchers found that babies born by C-section are five times more likely to develop allergies by age two than babies born naturally. Researchers looked at 1,258 babies between 2003 and 2007, and evaluated them at one month, six months, one year and two years. They collected samples from the baby’s umbilical cord and stool, blood samples from the parents, breast milk from the mother and household dust. A history of allergy and asthma was also taken.


    They also found that babies born by C-section have a pattern of “at-risk” microorganisms in their GI tract that make them more susceptible to developing IgE antibodies when exposed to allergens. This furthers the idea that early exposure to microorganisms affects the immune system in children and influences onset of allergies.


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    Prenatal pet exposure reduces risk of allergies

    Being around pets when you are pregnant may help your child remain allergy-free, according to a study published in 2011. Researchers looked at 1,187 newborns from August 2003 to November 2007. They collected blood samples, and measured IgE antibody levels at six months, one year and two years. Of the babies born, 751 were delivered vaginally, and 436 were delivered by C-section. At least one indoor pet was present in 420 homes.


    After analyzing the data, researchers found that IgE levels were 28 percent lower in babies who had indoor prenatal pet exposure compared to babies who were not exposed to pets. They also found that babies who were born vaginally and had prenatal pet exposure were less likely to develop allergies compared to babies who were exposed to pets but had been born by C-section.


    In addition, they found that infants who had prenatal pet exposure and were of European, Asian or Middle Eastern decent had 33 percent Iower IgE levels compared to 10 percent lower in infants who had prenatal exposure to pets and were African-American.


    Researchers say their findings support the hygiene hypothesis, and that exposure to diverse microbacteria in the home and during birth is good for a child’s immune system.


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    A mother’s exposure to microbes can protect kids from allergies

    According to a 2009 study, when pregnant mice are exposed to environmental bacteria triggers a mild inflammatory response that protects the offspring from developing allergies later in life. Researchers exposed pregnant mice to barnyard microbes, and found that they gave birth to allergy-resistant babies. They say the mild inflammatory response triggered by the exposure to microbes causes an increase in the expression of microbe-sensing receptors, and the production of immune molecules called cytokines. These receptors transmit protection, but it is not yet known how or how broadly the protection applies.




    Nordqvist, C. (2013, May 6). "Your Saliva On Pacifiers Can Ward Off Childhood Allergies." Medical News Today. Retrieved from


    Henry Ford Health System (2013, February 25). Babies born by C-section at risk of developing allergies. ScienceDaily. Retrieved from


    Henry Ford Health System (2011, August 10). Prenatal pet exposure, delivery mode, race are key factors in early allergy risk, study finds. ScienceDaily. Retrieved from


    Rockefeller University Press (2009, December 28). Microbes help mothers protect kids from allergies. ScienceDaily. Retrieved from


Published On: May 16, 2013