This is amazing: It seems how babies are born can impact their immune system. When compared with their nursery mates born by vaginal delivery, babies born by C-section appear to be at increased risk for food allergy.
But how can this be? How could the type of delivery affect risk for something like allergy to eggs? As it turns out, babies entering the world via mommy’s bottom are exposed to a variety of organisms that immediately begin to colonize and grow in the intestinal tract. Those born by C-section on the other hand are denied this apparently critical early bug exposure. Intestinal bacteria are critical in helping prepare the newborn immune system for what lies ahead. The immunology is dicey but suffice it to say it’s amazing and definitely not intuitive.
Could rising allergy rates be related to the popularity of the Cesarean delivery? Perhaps if you believe the hygiene hypothesis. This theory suggests that a lower exposure in early childhood to bacteria and other antigens in developed countries has led to inadequate development of immune responses with a resulting epidemic in allergy and asthma.
Cleaner, it seems, may not necessarily be better.