It's often been observed that
the explosive increases in asthma and allergies
we have seen over the past four decades have occurred
in tandem with widespread increases in antibiotic use.
Is there a link here? Yes, according to a new study
that examined the possible relationships between
antibiotic use, bacterial changes in the gut and
allergic response.
I spoke with Gary Huffnagle, PhD,
associate professor and researcher at the University
of Michigan Medical School in Ann Arbor where the
study was conducted. As we reported in Daily Health
News, August 14, 2003, antibiotics weaken natural
bacteria in the gut and, in humans, stimulate
overgrowth of the yeast Candida albicans. Previous
studies have shown that overgrowth of yeast adversely
affects the body's mucosal immunity. The result: A
weakened immune system that becomes vulnerable to
allergies and asthma.
The Study
In the University of Michigan
study, mice were given antibiotics in their
drinking water for five days to weaken their
gut bacteria. They were then injected with
candida yeast, to mimic the response that
antibiotics produce in humans. Finally, the
mice's nasal passages were exposed to aspergillus,
a mold spore that is a common allergy trigger
in humans.
The mice that received
antibiotics showed increased sensitivity to
the mold spore in their respiratory systems,
whereas mice that did not receive antibiotics
did not develop the sensitivities to mold.
The study reaffirms the
concept that what goes on in the gut can play
an important role in regulating immune responses --
even in the lungs, since they too secrete mucus.
And, to take the concept one step further, if a
problem in the lungs is found to originate at
another site in the body, there is little doubt
that other chronic diseases have their roots in
places not previously explored.
In an article in Trends in
Microbiology, Dr. Huffnagle and research colleague
Mairi Noverr, PhD, write, "The widespread use of
antibiotics and dramatic changes in the diet in
industrialized countries have been accompanied
by a striking increase in the incidence of allergies
and asthma. It is clear that the natural flora and
fauna of our bodies plays a significant role in
regulating immune responses.” When our bodies
fall out of balance, they respond in negative ways.
Moral of the story: Antibiotics,
like so many drugs, do not work in isolated ways.
Watch out for associated risks. Hopefully, one
day our medical system will strike a balance
between creating overall health and simply
curing isolated symptoms of disease.
Sources.
Gary B. Huffnagle, PhD, associate
professor and researcher, internal medicine,
University of Michigan Medical School, Ann Arbor.
