How Baby's Delivery Method and Diet Influence Immunity-Boosting Gut Bacteria

Typically, if all goes well, by a few weeks after childbirth, you can’t tell whether a baby was delivered vaginally or via c-section. And by the time your son or daughter is in preschool, you typically won’t be able to tell whether or not that child was exclusively breastfed. Despite all the controversy over parenting choices, most moms and dads do what’s right for their family at that time, and it all turns out just fine. But now, researchers are indicating there’s lasting evidence of each of these decisions. Both delivery method and diet can influence baby’s gut bacteria.

First, the delivery method findings: According to the JAMA Pediatrics study, babies delivered vaginally have more gut bacteria from the group Bacteroides, an important component of immune system development. On the other hand, c-section babies show higher levels of _Staphylococcus—yep, as in staph infection—_bacteria. However, researchers don’t yet know if this specific strain of bacteria is actually associated with staph infections.

Now, on to feeding differences. While babies who were exclusively formula-fed showed higher levels of the bacterium Lactococcus than breastfed babies, it’s currently unclear what that means for human health. Wondering about breastfed babies who are supplemented with formula? Their gut bacteria might not make them look like much of a breastfed baby at all.

“The gut microbiome of babies who receive formula supplementation to their breast milk really looks more like [the gut microbiome] of babies who have received only formula,” says study coauthor Dr. Juliette C. Madan.

The next steps? According to Madan, the team of researchers is aiming to better understand “how the gut microbiome works with training the immune system and how it relates to health outcomes in general.”