The healthy infant gut is an ecosystem much like a healthy ocean, and it's filled with trillions of microscopic bacteria. When environmental factors interfere with the natural balance — just as pollution does in the sea — this impacts the body’s ability to function at its best. Today, U.S. babies’ guts are less diverse than they used to be. Lacking a rich stew of microbial bacteria in infancy has been linked to autoimmune diseases such as type 1 diabetes, Crohn’s and celiac, as well as colic, asthma, eczema, and allergies, according to a June 2021 study published in Cell.
Naturally, an infant’s microbiome is influenced by their mother’s, research shows, but external factors also play a role. Over the past five decades, antibiotic use and C-sections have increased while rates of certain diseases have also jumped rapidly — suggesting environmental and societal factors influence the gut, not just genetics. For example, babies born in the U.S. lack some of the beneficial bacteria found in the guts of those born in less industrialized countries, researchers reported in a 2019 Nature paper.
“We are changing the transmission of the microbiome from generation to generation because of C-sections, early-life antibiotics and not breastfeeding at the most critical period of life,” says Martin J. Blaser, a microbiologist at Rutgers University and author of Missing Microbes: How the Overuse of Antibiotics is Fueling our Modern Plagues.
