A recent article in Discover Magazine details a study comparing the gut microbiomes of babies in industrialized communities and those in hunter-gatherer communities. Their composition is similar until around 6 months of age when industrialized babies begin to lose Bifidobacterium infantis, an important gut microbe that can digest human milk oligosaccharides (HMO) and may play important roles in preventing future immune and allergic diseases. The original research, published in Science, suggests that the initial similarity is due to limited environmental exposure of infants and their homogenous diet of mother’s milk. After the sixth month of life, industrialized infants start to diverge in their microbiome development from the Hadza infants, whose microbiomes continue on a similar trajectory, up to their third year. After the 6th month, industrialized infants lacked 20% of microbes present in the hunter-gather babies’ microbiomes. The reason for the difference could be maternal practices in industrialized countries, specifically the increased use of formula that lacks the human milk oligosaccharides that Bifidobacteria feed on. It is important to note that the study only examines the Hadza community of hunter-gatherers. As such, the results may not be generalizable to all hunter-gather communities. Nonetheless, the research highlights how lifestyle changes due to industrialization may have changed the development of our gut microbiota, which could be linked to the increased incidence of chronic disease in Western populations.