becomes less effective at spotting invaders, but sometimes
mistakenly attacks the body’s own cells. This is because a
diverse gut population not only teaches our immune system
guards who to watch out for, it also teaches them the
importance of tolerance. In a healthy gut there may be
hundreds or thousands of different species present at any
given time, and a healthy immune system benefits from this
plurality of voices. In fact, this is partly how probiotics are
believed to work: they consist of species that aren’t
normally resident in our microbiomes, flowing through us to
make sure our guards aren’t snoozing on the job.
Issues like allergies and autoimmunity develop when the
immune system makes a mistake and attacks its own host,
and the microbiome has become a focal point for scientists
working to figure out why this happens. It has been
proposed that our immune systems have become
dysfunctional for a number of reasons, including our overly
hygienic lives, antibiotic overuse, fiber inadequacy, and
birthing practices that place the developing microbiome as
an afterthought. Any one of these factors, it is believed, may
lead to stadium guards that aren’t as well trained—and thus
to higher rates of autoimmunity.
CLEANING OURSELVES SICK?
Something other than our food supply has changed over the
past couple of decades–we’ve become more sterile. But in
our preoccupation with eliminating any possibility of a stray
virus or pathogenic bacteria, we’ve essentially wiped clean