A disruption in one or more of these functions can lead to serious, sometimes lifelong, health problems. If, for example, gut maturation is impaired or delayed, some experts believe undigested proteins could leak into the bloodstream and trigger an allergy or gluten intolerance, or an impaired immune system could result in an autoimmune disorder like Type 1 diabetes, juvenile arthritis or multiple sclerosis.
Babies are exposed to some organisms in utero, but the organisms encountered during birth and the first months of life have the greatest influence on those that become permanent residents in their guts. Recent studies have shown that both a vaginal birth and exclusive breast-feeding can significantly affect the kinds and numbers of their gut microbes and the risk of developing various health problems.
For example, a Danish study of two million children born between 1977 and 2012 found that those born by cesarean delivery were significantly more likely than those born vaginally to develop asthma, systemic connective tissue disorders, juvenile arthritis, inflammatory bowel disease, immune deficiencies and leukemia.
Babies born vaginally primarily ...