How Breastfeeding Ramps Up Baby’s Immune System

A new study from a team of researchers at UCLA reveals yet another cool thing about breastfeeding. The benefits for mom and baby have been well-known for centuries, but as is often the case with many things in the domain of medical science, there's always more to learn. This latest research shows how breastfeeding ramps up baby's immune system through not just mom's milk, but her skin too.

Scientists have known for a while now that one of the major ways a newborn's immune system is bolstered is through gut bacteria, according to National Geographic. In fact, the relationship between colonies of bacteria in our digestive tracts and immunity has been established in adults, too: there are several studies that have linked breast feeding to a lower risk of inflammatory bowel disease throughout childhood and into adulthood, according to previous research published in the journal Pediatrics. But in those early days of life, babies need all the immune-boosting power they can get — and researchers have been very interested in understanding how that "good" bacteria gets delivered to a baby's burgeoning immune system. One of the major ways is from mom to baby via breast milk, which is teeming with that good bacteria.

A team of researchers at UCLA, lead by Dr. Grace Aldrovandi, looked at 107 baby-mom pairs over the course of a year for their study, which they hoped would help them better understand the mechanism (or mechanisms) that transfer that good gut bacteria from mom to baby. They found that as much as 30 percent of the healthy bacteria in a baby's intestinal tract came from mom's breast milk, which wasn't too surprising. But an additional 10 percent came from the skin of mom's breast — a previously unknown method of transfer.

“Breast milk is this amazing liquid that, through millions of years of evolution, has evolved to make babies healthy, particularly their immune systems,” said Dr. Aldrovandi, who is also the chief of infectious diseases at UCLA Mattel Children’s Hospital, in addition to being the study's lead author. She then added:

Our research identifies a new mechanism that contributes to building stronger, healthier babies. We're appreciating more and more how these bacterial communities, particularly in the intestine, help guard against the bad guys. We know from animal model systems that if you get good bacteria in your gut early in life, you're more likely to be healthy.

The researchers are hoping that they can use the findings of this study as a jumping off point to learn more about how the gut "microbiome" evolves throughout infancy, childhood, and adulthood. By gaining insight into the role gut bacteria plays in our overall, lifetime health, researchers could use studies like these to help identify what types of bacteria might be missing — or overabundant — in people with inflammatory bowel disease and even broader autoimmune diseases.