Scientists say don't discount that appendix

By Seth Borenstein , AP Science Writer
Wednesday, October 10, 2007 | 3 comment(s)

It's all about good bacteria

Font Size: Shrink Font Enlarge Font | Submit your news
WASHINGTON — Some scientists think they have figured out the real job of the troublesome and seemingly useless appendix: It produces and protects good germs for your gut.

That’s the theory from surgeons and immunologists at Duke University Medical School, published online in a scientific journal this week.

For generations the appendix has been dismissed as superfluous. Doctors figured it had no function. Surgeons removed them routinely. People live fine without them.

And when infected the appendix can turn deadly. It gets inflamed quickly and some people die if it isn’t removed in time. Two years ago, 321,000 Americans were hospitalized with appendicitis, according to the Centers for Disease Control and Prevention.

The function of the appendix seems related to the massive amount of bacteria populating the human digestive system, according to the study in the Journal of Theoretical Biology. There are more bacteria than human cells in the typical body. Most of it is good and helps digest food.

But sometimes the flora of bacteria in the intestines die or are purged. Diseases such as cholera or amoebic dysentery would clear the gut of useful bacteria. The appendix’s job is to reboot the digestive system in that case.

The appendix “acts as a good safe house for bacteria,” said Duke surgery professor Bill Parker, a study co-author. Its location — just below the normal one-way flow of food and germs in the large intestine in a sort of gut cul-de-sac — helps support the theory, he said.

Also, the worm-shaped organ outgrowth acts like a bacteria factory, cultivating the good germs, Parker said.

That use is not needed in a modern industrialized society, Parker said. If a person’s gut flora dies, they can usually repopulate it easily with germs they pick up from other people, he said. But before dense populations in modern times and during epidemics of cholera that affected a whole region, it wasn’t as easy to grow back that bacteria and the appendix came in handy.

In less developed countries, where the appendix may be still useful, the rate of appendicitis is lower than in the U.S., other studies have shown, Parker said.

He said the appendix may be another case of an overly hygienic society triggering an overreaction by the body’s immune system.

Even though the appendix seems to have a function, people should still have them removed when they are inflamed because it could turn deadly, Parker said. About 300 to 400 Americans die of appendicitis each year, according to the CDC.

Five scientists not connected with the research said that the Duke theory makes sense and raises interesting questions.

The idea “seems by far the most likely” explanation for the function of the appendix, said Brandeis University biochemistry professor Douglas Theobald. “It makes evolutionary sense.”

The theory led Gary Huffnagle, a University of Michigan internal medicine and microbiology professor, to wonder about the value of another body part that is often yanked: “I’ll bet eventually we’ll find the same sort of thing with the tonsils.”

———

On the Net: The Journal of Theoretical Biology:

http://www.sciencedirect.com/science/journal/00225193
Tags »
Previous

Have you checked out The World Link Forums?

Comments

The comments below are from users of theworldlink.com and do not necessarily represent the views of The World or Lee Enterprises. Participation Guidelines

Note: There is a maximum of 200 words per comment. If you wish to post more, please visit our forum.
Comment Policy

The World welcomes your comments about stories, and we encourage a robust dialogue on this site. All comments must meet reasonable standards of decency and civility.

Please follow these basic rules:

  • No defamatory comments about individuals or businesses.
  • No deliberately false information.
  • No obscenity or racially offensive language.
  • No harassment, verbal abuse, threats or personal attacks.
  • No information that invades another person's privacy.
  • No business solicitations or charitable solicitations.
Comments that violate these standards will not be posted. Users with repeated violations may be banned from future posting.

Comments will be approved throughout the day during business hours. After hours and weekend comments may not appear until the following business day. It may take a couple of hours before comments are approved.

The World generally does not edit comments, but we reserve the right to edit any comment that does not meet our standards.

Close Guidelines

D wrote on Oct 9, 2007 8:46 PM:

you're short like three zeros Tral. 321,000 is about the size of the Eugene/Springfeild area.

Tral wrote on Oct 8, 2007 6:48 PM:

"Two years ago, 321,000 Americans were hospitalized with appendicitis, according to the Centers for Disease Control and Prevention." The U.S. population is 300,000.

DESTINY wrote on Oct 8, 2007 2:58 PM:

SWEEET NESS LY COOL


*Member ID:
*Password:
 

Not already registered?

Do not use usernames or passwords from your financial accounts!

Note: Fields marked with an asterisk (*) are required!



*Create a Member ID:
*Choose a password:
*Re-enter password:
*E-mail Address:
*Year of Birth:
 

(children under 13 cannot register)

*First Name:
*Last Name:
Would you like to be added to our mailing lists?
Daily Headlines
Breaking News
Special Offers
 
Advanced Search
Web Search powered by YAHOO! SEARCH

Blogroll

Most Popular

Polls

» View Past Poll Results
» Suggest a Poll

Marketplace

Special Sections

More Special Sections