Bringing Up Baby: New Focus on the Gut Microbiome in Infancy
By now it’s old news that “we” are really more “them” than “us”. By “them,” I’m referring to the microorganisms (meaning bacteria, for the most part) that live in and on our bodies. Unwittingly playing host to these friendly microscopic passengers is completely normal, and it’s usually highly beneficial—for us and for them. Indeed, these single-celled creatures are especially important in the human digestive tract. Cell for cell, microbes outnumber us by more than 10 to 1.
Emerging evidence shows that they directly or indirectly affect everything from immune system function, to nutritional status, to mood—and that’s just for starters. Clearly, these friendly microbes are not to be ignored when it comes to human health. Taken together, the diverse communities of different types of microbes living in the human gut are referred to as the gut microbiome.
In recent years, technological advances have allowed scientists to comprehend this previously hidden world better than ever before. Although still somewhat murky, a picture is gradually emerging, which suggests that healthy people tend to host highly diverse collections of microbes, with specific characteristics. In general, it appears as if certain species of bacteria are especially beneficial to health.
Some of these same species thrive in fermented foods, such as yogurt, which may help explain the healthful reputation these foods enjoy. It also appears as if more diversity in the gut microbiome is better than uniformity.
Given the dawning realization that we can no longer ignore our microbes if we are to fully comprehend human health, researchers in Sweden recently addressed the question of birth, infancy, and gut microbiome diversity. What they discovered is fascinating. Essentially, babies delivered vaginally tend to have microbiomes that resembled that of their mothers. In contrast, when babies were delivered by cesarean section, their gut microbiomes did not closely resemble their mothers’.
Nor surprisingly, breast feeding also played an important role in the development of the microbiome. It wasn’t just about breast feeding versus formula feeding, either. After a baby’s gut is colonized following delivery, the biggest factor in determining any changes in its makeup appears to be nutrition. Interestingly, babies that were breastfed the longest appeared to retain the most beneficial bacterial species.
”Our findings surprisingly demonstrated that cessation of breastfeeding, rather than introduction of solid foods, is the major driver in the development of an adult-like microbiota," said lead study author Fredrik Bäckhed, of The University of Gothenburg, Sweden. "However, the effect of an altered microbiome early in life on health and disease in adolescence and adulthood remains to be demonstrated.”
Check back tomorrow for more on the fascinating issue of your baby’s gut microbiome and long-term health.
Bäckhed et al. Dynamics and Stabilization of the Human Gut Microbiome during the First Year of Life. Cell Host & Microbe, May 2015 DOI: 10.1016/j.chom.2015.04.004