HOUSTON – Findings from a cohort study of mothers and babies point to breastfeeding as influencing infants’ gut microbiome in a way that protects them from developing allergic disease.
In findings presented at the annual meeting of the American Academy of Allergy, Asthma, and Immunology, epidemiologist Christine Cole Johnson, Ph.D., of the Henry Ford Health System in Detroit described a correlation between certain maternal and birth characteristics that had previously been shown to relate to allergic response, and measurable differences in the bacterial profiles of the study infants’ stools.
Using data from the WHEALS (Wayne County [Michigan] Health, Environment, Allergy, and Asthma Longitudinal Study) cohort, Dr. Johnson and her colleagues looked at stool samples from 298 children at 1 and 6 months of age. The investigators also collected dust samples from the infants’ homes, obtained medical records, and conducted interviews with the families (J. Allergy Clin. Immunol. 2015 [http://dx.doi.org/10.1016/j.jaci.2014.12.1443]).
The presence of household pets, the body mass index of mothers before delivery, the mode of delivery, household smoke exposure, marital status, income, race, and maternal education were all found to be significantly correlated to different gut bacterial profiles.
“Environmental and lifestyle variables that we’ve been working on related to childhood asthma and allergy seem to be associated – at least in our study – with the child’s gut microbiome,” Dr. Johnson said. “These factors vary a lot by whether those stool samples were collected at 1 or 6 months,” she said, noting that the infant gut microbiome is shaped rapidly in the first year.
But, at both 1 and 6 months of age, breastfeeding was seen as the dominant factor influencing gut bacterial composition.
At 6 months, breastfed infants had bacterial profiles showing overwhelming dominance of Bifidobacteriaceae, but vastly lower levels of other families of bacteria, notably Lachnospiraceae, which were prominent in the guts of non-breastfed babies.
In a related study that used the same cohort to explore whether the influence of breastfeeding on gut bacterial composition correlated to the development of allergic symptoms at 4 years old, Alexandra R. Sitarik, also of the Henry Ford Health System in Detroit, reported that babies being breastfed at 1 month of age had a significantly lower risk of developing allergiclike symptoms to pets by age 4 years (P = .028) (J. Allergy Clin. Immunol. 2015 [http://dx.doi.org/10.1016/j.jaci.2014.12.1444]).
Both breastfeeding and allergiclike response to pets were significantly related to compositional variation in gut microbiome (P < .001 and P = .023, respectively), Ms. Sitarik reported.
Of the 109 types of bacteria significantly associated with both breastfeeding and allergiclike response to pets, 71% were negatively associated with breastfeeding but positively associated with allergiclike response to pets.
This subset of risk-increasing bacteria suppressed by breastfeeding were predominantly members of the family Lachnospiraceae, the researchers found.
Lachnospiraceae are common adult gut colonizers, Ms. Sitarik said, and as people age the relative abundance of Lachnospiraceae increases. “What we think might be happening in terms of the gut microbiome is that maybe breastfeeding is preventing this premature shift into adulthood,” she said.
Dr. Johnson and Ms. Sitarik reported having no financial disclosures.