By Tanya Altmann MD

The infant gut microbiome is made up of thousands of different bacterial strains. Some of these strains are considered “good” and can help build important things like immunity and metabolism. Others, like E. coli and Strep, are considered “bad” and can lead to infection, illness, and health conditions like colic, eczema, allergies, and asthma. All of these bacteria strains, both good and bad, live under the same roof (a.k.a. the baby’s gut microbiome). Research has identified one good bacterial strain, however, that is clinically proven to be indispensable for baby. It’s called B. infantis, and all new moms should know about it.

B. infantisis perhaps the most important gut bacteria an infant can have in his or her gut. It is responsible for fortifying a strong immune system, fostering a healthy metabolism, and conditioning a microbiome that is better prepared to ward off future health issues like eczema, allergies, asthma, and obesity.

This is extremely important. As a pediatrician, I’ve seen a massive spike in these maladies among kids, and the scientific community agrees that they have become epidemics among American children in the past few decades. Here are the facts:

Here’s the kicker. These growing statistics are related to immune health and the gut, and they appear to be correlated with the near extinction of B. infantis, in particular. Research shows that only one in 10 babies today has B. infantis in their gut. That leaves 90 percent of our infant population completely void of this “creme-de-la-creme” gut bacteria that helps ward off bad bacteria that cause these health conditions. But that wasn’t always the case. Three generations ago, almost every single baby in the United States and other developed countries acquired B. infantis at birth. So what happened?

Where did B. infantis go?

As a pediatrician, I am all about modern medical interventions, but I am also acutely aware that with all modern technology can come unintended consequences — and this is the case with the missingB. infantis.

Historically, B. infantis was passed from mom to baby via an oral fecal matter transfer that occurred during vaginal delivery. When C-sections became more prevalent, however, this important transfer stopped happening, and fewer guts were colonized with B. infantis. In fact, if you were born via C-section yourself, you probably never had B. infantis to pass along to your child in the first place, even if you delivered your baby vaginally. And to add to that, our widespread use of antibiotics (for both mom and baby) have helped drive B. infantis’ near extinction. For instance, any mom that tested positive for Group B strep received heavy doses of antibiotics in her third trimester, likely wiping out many beneficial bacteria.

How we get it back.

The good news for infants is that even if they don’t acquire B. infantis when they are born (the vast majority of babies today), there is still a clinically proven way to get it back via a baby probiotic that has activated B. infantis. Such a probiotic, when paired with breast milk, actually colonizes the gut with B. infantis. This reduces bad bacteria linked to gas, colic, eczema, and more that would otherwise have flourished. But be aware, our window for getting this done is tight – it’s most important to do so in the first six months of baby’s life when important immune system and metabolic development occurs.