Does breastfeeding protect against asthma?

Asthma is the most common chronic disease in children. According to the American Academy of Pediatrics (AAP), 10–15 percent of U.S. schoolchildren have or have had asthma, and the incidence continues to rise. Although asthma symptoms can appear at any age, 80–90 percent of childhood cases are diagnosed by the time a child is 5 years old.

The causes of childhood asthma are not fully understood, and while symptoms can be managed, it is difficult to determine what, if anything, can be done to prevent a child from developing asthma. Breastfeeding has been associated with a reduced risk of asthma in some, but not all, studies.

The New Zealand Asthma and Allergy Cohort Study was one of the largest investigations of breastfeeding and asthma. Researchers followed more than 1,000 children from birth to age 6 and concluded that breastfeeding reduced their risk of asthma. The effect was dose-dependent, meaning, the longer a child was exclusively breastfed, the greater the protection. But given the observational nature of the study, other factors may have influenced the results.

More recent studies suggest that breastfeeding provides little or no protection against childhood asthma.

A meta-analysis involving data from 20 countries concluded that breastfeeding did not protect against wheezing (due to allergy or otherwise) in affluent countries such as the U.S. Investigators did find that breastfeeding was associated with less wheezing among children in nonaffluent countries, but this was only the case for wheezing that was not related to allergy (non-atopic).

In the U.S., where most asthma is atopic (allergy related), breastfeeding is not thought to provide protection. Which explains why in a recent analysis of maternal and pediatric health outcomes and costs related to breastfeeding, researchers deliberately omitted asthma. Similarly, an international team of researchers noted in their large-scale meta-analysis of the “lifelong effect” of breastfeeding no association between breastfeeding and allergic disorders such as asthma.

Although breastfeeding may not protect children against asthma, data show that it does support the development of their immune and respiratory systems. And in that way, breastfeeding does reduces the risk of infection that can trigger asthma symptoms.

To learn more about childhood asthma, including when to implement an asthma action plan, read this.

Last updated May 17, 2020

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