WebMD Medical News
Louise Chang, MD
Oct. 12, 2007 -- The lowly appendix may have a purpose after all.
New research suggests that the seemingly useless organ provides a safe haven
for good bacteria to hang out in the gut.
Although the study stops short of providing direct proof of this proposed
purpose for the appendix, researchers say there's a strong case to be made for
the appendix based on new information about the role of bacteria in intestinal
"While there is no smoking gun, the abundance of circumstantial evidence
makes a strong case for the role of the appendix as a place where the good
bacteria can live safe and undisturbed until they are needed," researcher
William Parker, PhD, assistant professor of experimental surgery at Duke
University Medical Center, says in a news release.
The appendix is a small, 2- to 4-inch pouch located near where the large and
small intestines meet. Doctors have debated the exact function of the organ for
years, as removal causes no noticeable symptoms.
Not much is known about the human appendix because studies on the appendix
are difficult to conduct. There are only a few animals that have the organ; an
animal's appendix is very different than the human appendix.
Researchers deduce that the appendix is designed to protect good bacteria in
That way, when the gut is affected by a bout of diarrhea or other illness
that cleans out the intestines, the good bacteria in the appendix can
repopulate the digestive system and keep you healthy.
But in a modern society less of these good bacteria are needed due to better
hygiene practices, which may explain why the appendix has gained a reputation
as a useless organ.
"Once the bowel contents have left the body, the good bacteria hidden
away in the appendix can emerge and repopulate the lining of the intestine
before more harmful bacteria can take up residence," says Parker. "In
industrialized societies with modern medical care and sanitation practices, the
maintenance of a reserve of beneficial bacteria may not be necessary. This is
consistent with the observation that removing the appendix in modern societies
has no discernable negative effects."
In addition, according to the hygiene hypothesis, the lack of germs in
modern society may cause the immune system to overreact and attack the good
bacteria stored away in the appendix.
"This over-reactive immune system may lead to the inflammation
associated with appendicitis and could lead to the obstruction of the
intestines that causes acute appendicitis," Parker says. "Thus, our
modern health care and sanitation practices may account not only for the lack
of a need for an appendix in our society, but also for much of the problems
caused by the appendix in our society."
SOURCES: Bollinger, R. Journal of Theoretical Biology, August 2007;
vol 35: 1295-1303. News release, Duke University Medical Center.
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