Wednesday
February 16, 2005
news@michigandaily.com

SCIENCE

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Antibiotics use linked to allergies

By Caitlin N. Murphy
For the Daily
After years of inhalers and decongestant
prescriptions, the cause of your allergies may
not be the pollen in the air after all, but the
contents of your gut.
Antibiotics can cause changes in the
human digestive system that, coupled with
an unhealthy diet, could be responsible for
recent increases in the development of aller-
gies and asthma, according to research find-
ings released Dec. 23 from the University
Medical Research Center.
"Antibiotics are great. They are, but there
is a price to pay, and that's what we have
ignored", said Gary Huffnagle, a profes-
sor of internal medicine, microbiology and
immunology. Huffnagle, the head researcher
on the project, and Mairi Noverr, a Universi-
ty postdoctoral fellow, developed a study to
test their hypothesis that antibiotics change
the microflora lining - a mixture of fun-
gus and bacteria in the gastrointestinal tract
or the system of organs that digests food.
According to their research findings, this
change disrupts the immune system and its
ability to ignore inhaled allergens.
Noverr exposed the laboratory mice to a
broad-spectrum antibiotic, which kills a wide
range of bacteria, for five days to kill their
gut bacteria. Then, to help the mice quickly
redevelop a bacterial mix in their GI tract,

they were exposed to Candida albicans, a
type of yeast normally found in the GI tract.
Two days later, the mice were exposed to
ovalbumin, an experimental allergen known
to illicit an allergic response. Comparing the
mice that received the antibiotics to those
that did not, Noverr found that the mice
treated with the antibiotic were much more
sensitive to the allergen.
Now that they have found a correlation between
the GI tract the immune system, Huffnagle and
Noverr want to determine how the gut microflora
communicates with the immune system.
Noverr said that special cells called regu-
latory T cells, which are generated in the GI
tract, help to maintain tolerance to allergies.
Huffnagle and Noverr believe these cells
can travel to other mucosal surfaces, such as
the lungs, where they can dampen immune
response. They plan to investigate whether or
not changes in microflora influence the devel-
opment of regulatory T cells.
Their current results confirm their hypothesis
that the increase in allergies, asthma, and many
other diseases over the last 40 years in Western
industrialized societies can be credited to the wide-
spread use of antibiotics, Huffnagle said.
Noverr said they are interested next in
studying the effect of environmental factors,
particularly the effects of various diets on
microflora and allergies. Scientists have sug-
gested that the "western diet," which is high
in processed fat and sugar is responsible for

"Antibiotics are great ... but there is a price
to pay, and that's what we have ignored."
- Gary Huffnagle
University professor of internal medicine

a number of health problems. They
hypothesized that today's modern diet
does not provide the body with appro-
priate nutrients to maintain a healthy
mix of microflora in the GI tract.
Huffnagle said he hopes that anti-
biotic prescriptions will eventually
be accompanied by supplemental
dietary instructions after the med-
ication's use ends, to help rebuild a
healthy mix of microflora.
Such a diet should be high in raw fruits
and vegetables, he explained, since other
laboratory results have shown that plants
produce dietary antioxidants the human
body needs to fight infection. These

antioxidants, concentrated primarily in
the rind or skin of fruits and vegetables,
could help to restore the normal mix of gut
microflora.
Results of the study, as well as a multi-
tude of anecdotal evidence also suggest
that many people who have developed
allergies may be able to alleviate their
allergy symptoms simply by making
dietary changes, Huffnagle said
And, Huffnagle and Noverr suc-
ceed in determining how microflora
in the GI tract communicates with the
immune system, treatment or preven-
tion of allergies and inflammatory
diseases may become a reality.

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A microscopic view of pollen grains carried on the body of
} a wasp. Two University professors are researching the link
between the use of antibiotics and the rise in allergies.

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