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in The beginning, There were single-Cell baCTeria.
They were the only life on earth for billions of years, then larger
cells evolved, then multicellular organisms, and then plants and
animals. But the bacteria never went away, and all organisms,
including us humans, have had to learn to live with them. Today,
the lessons they are teaching us could change the trajectory of
human health for generations.
When bacteria were first discovered more than three centu-
ries ago, most attention was on the ones we fought, which caused
diseases like cholera, typhoid and tuberculosis. Through vac-
cines and antibiotics, we have made amazing progress in con-
quering these scourges. Now, through the combined tools of
DNA sequencing and computer-based analysis, we have a first
approximation of the innumerable other bacteria with which
we cooperate daily.
Our microbiome is a diverse array of microbes—bacteria,
as well as viruses, fungi and protozoa—that are more or less
unique within each of us. We now understand that many are
inherited, mostly from Mom, and this represents a continuity
of life going back millennia. We know that the microbiomes of
peoples living in the forests and
savannas —who have had few of
the benefits of modern medi-
cine—have much more diverse
microbiota than those in indus-
trialized countries do. These
comparisons strongly suggest
that as the world modernized,
we lost much of our microbial
heritage.
And there’s increasing evi-
dence that those changes are
linked to the rise of modern
diseases like obesity, diabetes,
asthma, food allergies and inflammatory con-
ditions of the intestine and of the brain. The
same progress that has made us healthier in
some ways has had unintended collateral ef-
fects on our ancient microbiome, putting it
under great stress. These advances include,
among others, food preservatives and, most
important, the very thing we’ve long used to
fight disease-causing bacteria : antibiotics.
As A society we have become addicted to
antibiotics. They are great drugs for serious
illnesses, but are being used more and more
to treat ever milder conditions, in which their
net positive effects are marginal. Even tran-
sient anti biotic exposures, especially in early
life, can lead to long-term consequences like
obesity—or, paradoxically, an increased risk
of infection in subsequent months. Exposures
of women before the birth of their children
can lead to consequences in the next genera-
tion, and exposures of adults can enhance risk
of diabetes, kidney stones and certain cancers.
We clearly have to restore our lost microbes.
Meanwhile, my colleagues and I have been
working to create a microbiota vault, where we
can preserve our ancestral microbes for future
generations, before many other important ones
become extinct. Thankfully what we’ve learned
in recent years about the microbiome may en-
able us to live more collaboratively with bacte-
ria. In the not so distant future, for example, pe-
diatricians may examine both babies and their
diapers to determine whether that infant has
an ideal microbiota, based on their genes and
other markers. If not, they will be able to ad-
minister the “missing microbes” to optimize
the baby’s health trajectory.
To fully harness the microbiome for therapy
with true scientific basis will take time; in the
interim, we need to educate people to avoid
modern “snake oils” ranging from so-called
probiotics to microbiome mapping that doesn’t
actually tell you anything.
Imagine it’s 1950 and someone says to you,
“There is a new field out there that is going to
change how we do things, how we live... and
the name of the field is ‘electronics.’ ” Today,
we see how broad the implications of that have
been, affecting virtually every aspect of modern
life. That is how I believe we will be thinking
about the microbiome some years from now;
it is that big—maybe bigger—with the poten-
tial to make real improvements in our health.
Blaser is a professor at Rutgers University
and director of its Center for Advanced
Biotechnology and Medicine
As the world
modernized,
we lost
much of our
microbial
heritage
VIEWPOINT
Human health
is in the hands
of bacteria
By Martin J. Blaser
ILLUSTRATION BY JON STICH FOR TIME