E. coli and the future health of America
Jeff D. Leach
In 2006, Americans learned that a salad could be hazardous to your health. The media flurry and the elected official posturing that followed the September 14 outbreak of E. coli 0157:H7 associated with spinach, is still fresh on American minds and making daily headlines thanks in no small part to the brisk recalls associated with tainted beef.
So is our food supply less safe and are the growers, shippers and various groups and agencies tasked with oversight not doing all they can to protect the consumer from deadly microbes as some believe? While the media and the public at-large lays blame at the doorstop of industry and government, might the brunt of this burden be misplaced? Simply, are we so involved in finger pointing, fences and hairnets that we don’t see the forest for the trees? An evolutionary perspective on the problem suggests, maybe.
Forgetting for a moment that the latest deadly microbe on the scene originates in cows, one needs to come to grips with the fact that the microbes have us out numbered. When a handful of rich soil contains tens of millions of tiny microbes, and that a single leaf of spinach may be covered in millions more, you start to get a feel for the germ warfare we are up against. Even worse, our so-called modern diet which is dominated by highly-processed grains and added sugars and fats, is putting us at significant disadvantage in the battlefield that is us.
But evolution has equipped humans with an ingenious system for defending against this daily microbial onslaught, most of which are harmless. Our very own microbial foot soldiers, which set up shop in our guts the minute we entered this world. There are so many microbes in the human body that if you added up their total number of cells, they would out number our human cells 9 to 1. In other words, we are more microbe than mammal.
The vast majority of the trillions of bacteria that live in our gut, most of which can be found in our large bowel and represent hundreds of species, make it their evolutionary job to keep out the pathogens that seek to do us harm. In this complex bacterial ecosystem, potentially pathogenic bacteria (e.g., E. coli 0157:H7, Salmonella, Listeria) from the “outside” world are typically suppressed by a mechanism called colonization resistance. Since the human intestinal tract is a continuous system from mouth to anus, anything present within our gut is technically still outside our body. That said, a deadly strain of E. coli does very little harm as it travels through our gut, it’s when it attempts to attach to the wall of our intestinal tract that problems occur.
In order for deadly pathogens to attach, they must compete for nutrients and colonization sites under a steady fire of microbial substances being hurled at them by our resident gut bugs. No doubt about it, this is germ warfare 101 and our gut bugs want to win. If our microbial foot soldiers are successful, then the pathogen cannot gain a foothold and consequently are swept from the system. If they are not suppressed, we quickly become aware of the lost battle from the all-to-familiar gut ache, cramping, and diarrhea, or even worse, death.