and only half of these patients with severed nerves
developed Parkinson’s disease over twenty years, compared
to rates seen in the general population. This is strong
evidence that Parkinson’s disease might in fact begin in the
GI tract and travel up the vagus nerve to the brain.^46
Fecal microbiota transplantation—the transplantation of
healthy stool that is up to 60 percent bacteria by weight—is
an exciting development because it provides an opportunity
to press “reset” on the gut microbiome. Today, this
procedure involves transplanting intact stool, which can
contain thousands of types of bacteria. Scientists do not yet
know exactly which ones hold the curative powers, but in
the future, the potential for more selective bacterial
interventions on a whole host of conditions will
undoubtedly emerge.
It’s important to remember that the gut microbiota is but
one element of our human-microbial symbiosis. Emerging
areas of research include the oral and sinus microbiomes.
Poor oral health has been long linked to a number of
systemic illnesses, including stroke, diabetes, cardiovascular
disease, and dementia.^47 In a paper published in PLOS ONE,
researchers found that patients with mild to moderate
dementia with periodontitis—gum inflammation—had a
sixfold increase in the rate of cognitive decline six months
later.^48 Should we be swishing with antibiotic mouthwash,
essentially nuking the friendlier bacteria populations in our
oral microbiome along with those that may be more
harmful? Do the same opportunistic species found in the gut
lurk below the gumline, waiting for the right moment to