This theory has been around for awhile but it recently has gained more credibility thanks to work of Tom McDade of Northwestern University in Evanston, Illinois.  In a study released 12/9/09 entitled, “Early Origins of Inflammation: Microbial Exposures in Infancy Predict Lower Levels of C-reactive Protein in Adulthood,” he and his team examined the health surveys of over 1500 children living under what the Western world would consider unhygienic conditions. At the age of 20, their blood was tested for C-reactive protein, a marker of chronic inflammation.

This study found that levels of CRP were 80% lower in this population compared with their American counterparts. In keeping with the findings, cardiovascular disease, obesity and diabetes were also significantly lower in the Phillipines than in the U.S.

McDade speculates that this early exposure to pathogens actually decreases the amount of CRP found in the blood and that therefore, this may reduce the chance of developing heart disease and diabetes as well as other diseases that are being associated with chronic inflammation.

The hypothesis is that our immune system learns how to turn itself on and off when it is exposed to a certain level of pathogens found in our environment. When this doesn’t occur, the theory is that the immune system inappropriately releases certain proteins that increase inflammation.

In an article published by the Northwestern University, McDade said,

“In the U.S we have this idea that we need to protect infants and children from microbes and pathogens at all possible costs,” McDade concluded.

“But we may be depriving developing immune networks of important environmental input needed to guide their function throughout childhood and into adulthood. Without this input, our research suggests, inflammation may be more likely to be poorly regulated and result in inflammatory responses that are overblown or more difficult to turn off once things get started.”

So, maybe it’s about time for some parents to stop being overly-protective of their child when it comes to dirt and germs?