I remember one day during my pediatric gastroenterology fellowship, a mother and child were walking in front of my professor and me, as we made our daily rounds in the hospital. When the pacifier fell out of the toddler’s mouth and the mother picked it up and put it right back into the child's mouth, my professor remarked to me, "mark my words....that child will never get Crohn’s disease!" My professor was referring to the theory of the "Hygiene Hypothesis". This theory is thought to explain (at least in part) why so many more people in developed nations become afflicted with autoimmune diseases such as Inflammatory Bowel Disease (IBD - Crohn's disease and Ulcerative Colitis) as well as food allergies, compared to people in non-developed nations.
In non-developed countries, where children are more often exposed to bacteria and infections, children’s immune systems seem to learn to live symbiotically with these infectious agents. On the other hand, in the Western world, where we tend to use a lot of antibiotics, antimicrobials and disinfectants, our drive to make our environments “super-sanitized” may lead to our children not having adequate exposure to even “normal levels” of bacteria. This in turn, may lead to inappropriate over-stimulation of children’s immune systems when encountering a relatively harmless bacteria or virus. This over-stimulation could then trigger an inflammatory cascade that culminates in the development of an autoimmune disease such as IBD.
I found this topic, the balance between our bodies and bacteria, nicely discussed in a recent New York Times article, written by Mr. Michael Pollan - click here to read it.
