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E.
coli and the future health of America
By 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.
This
germ warfare has been raging in the human gut for as long as humans have
been around. But recently, breath taking changes in our diet has put us
at a disadvantage. In order for our gut bugs to fight the good fight,
they need nutrients and a critical component of that nutrient base is
dietary fiber. By definition, dietary fiber is any part of a plant that
cannot be digested and absorbed in the small intestine and ends up in
the large bowel (colon). Once in the colon, dietary fiber is broken down
and utilized by our good bugs for their own growth. This means, dietary
fiber is not food for us but food for the trillions of bacteria that
live in our colons. If you feed them, the bacteria will do their
evolutionary job and make life a living hell for foreign pathogens.
Our
modern genome and the symbiotic relationship we developed with our gut
bugs was selected on a nutritional landscape very different from the one
we find ourselves today. Our not-so-distant ancestors consumed between
50, 75 and up to often greater than 100 grams a day of dietary fiber.
The average American today consumes between 12 to 15 grams. More
importantly, our gut bugs evolved on a diet that included an
extraordinary variety of fiber sources from hundreds of plants. Humans
and our evolutionary hitchhikers went from a large quantity and
diversity of fibers, to a small quantity and a limited diversity. We are
literally starving our gut bugs to the point that we have opened the
pathogen door just enough for E. coli 0157:H7 and its band of pathogenic
brothers to compete successfully for nutrients and attachment sites. Not
good.
The
decrease in quantity and diversity of nutrient sources (dietary fiber)
has created a nutritional tipping point in the germ warfare raging in
the American gut. While increased oversight, inspections, sampling and
stepping up good agricultural practices are important, there are simply
too many contamination variables from plough to plate. So rather than
look at the recent spike in outbreaks as a result of more pathogens in
the food supply and sloppy farming, might the problem have more to do
with our own dietary choices. That is, our breathtaking drop in the
diversity and quantity of dietary fiber might be the real problem – or
at least part of the problem. In other words, dare I say, there is some
personal responsibility the American public has in this germ warfare.
When
someone spends a lifetime smoking two packs a day, are they not aware
that if they succumb to lung cancer, that it’s in affect their own
fault? So where is the personal responsibility in our national
discussion on food-borne illness and the produce industry we seek to
blame? Rather than run from spinach, let us run to it.
As
the amount of dietary fiber in the American diet continues to decrease
– and probably even more so since last years outbreaks – and our
ignorance of the consumers responsibility in this germ warfare
continues, we may be seeing a perfect storm of our own creation –
though unintended. The litigious atmosphere surrounding this perfect
storm has already created the
potential for a public that sees diarrhea
as a result of a nasty microbe as something akin to a winning lottery
ticket. And the situation is likely to get worse.
However,
the public’s current mistrust of the produce industry may be an
opportunity. Though tragic in its realization, the microscope the
industry is currently under may provide a platform to explore some
positive steps the industry might take in educating the public about how
to increase their natural resistance to food-borne pathogens by
returning the quantity and diversity of dietary fiber needed to support
a healthy population of gut bugs. By consuming more vegetables and
fruits, the American public may be able to add another weapon in our
arsenal in our battle with food-borne pathogens and importantly, own
some of the responsibility in this germ warfare. Currently, the consumer
is totally unaware of the important role they play in keeping themselves
and their family members healthy.
The
produce industry does not need to wait until tomorrow to start this
process, but start today. On September 14, 2006 the produce stepped
through a door and there is no going back. It’s time to reposition
produce in the American conciseness. The antioxidant and other
micronutrient wagons the industry has hitched itself to in the past is
tired and the American public has been yawning at that message for
years. The American public needs a reason to eat more produce, something
new, something fresh. Significant gains may be realized if produce is
positioned more as fiber – that is, produce farmers are in fact fiber
farmers. This “Fiber Defense Diet” may in fact play a role in a much
need rallying call for produce in America and give consumers a very
important reason to increase intake.
Some
may suggest that the fiber defense argument for fighting food-borne
pathogens is too simple, and therefore could not possible make a
difference. And they may be right. However, the human immune system and
accompanying colonization resistance mechanism that is facilitated by
our own natural gut bugs, makes all external attempts such as fences,
increased inspections, and triple washing look like child’s play. Our
best defense has always been and will always be our natural resistance.
Not nurturing our gut bugs with the nutrients they need has
consequences. Continuing to ignore this basic tenant of human biology
will only result in an increasing number of our fellow citizens in the
emergency room and decreased sales at the farm gate.
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