Appendix

The appendix is an important component of the digestive system also known as the vermiform appendix or cecal appendix. It is a blind-ended tube connected to the cecum (a pouch-like structure of the colon), which assists with the fermentation of cellulose (plant fiber).

Many cite the human appendix as a vestigial organ - a remnant of an intestinal pouch. The appendix in orangutans and grazing animals is much larger. For that reason a number of critics of creationism and of intelligent design have claimed the appendix as a counterexample of intelligent design.

Regulating intestinal flora
Recent studies have indicated that the appendix does have a function that goes beyond the digestion of grasses and vegetables. The appendix contains a large number of lymphoid follicles, which it can use to control which bacteria come to reside in the colon as the intestinal flora. Thus, during infancy, the appendix might protect the baby from foreign agents that its still not-quite-developed immune system cannot combat effectively.

Ken Ham and Carl Wieland comment on the appendix function: [I]t is likely that the appendix plays its major role in early childhood. It is also probably involved in helping the body recognize early in life that certain foodstuffs, bacterially derived substances, and even some of the body’s own gut enzymes, need to be tolerated and not seen as ‘foreign’ substances needing attack.

This would explain why emergency appendectomy later in life does not appear to compromise an adult patient or even an adolescent patient. (However, some observers now dispute the claim that an adolescent or adult can get along without an appendix as easily as with one; see below.)

More recent research has demonstrated that the appendix might also assist in helping the body tolerate the symbiotic bacteria that populate the large intestine beginning early in life. In 2004, Jan-Olaf Gebbers and Jean-Albert Laissue found that as the lymphoid tissue in the appendix continues to develop (generally within two weeks of birth), bacteria are often found within that tissue, either because they invade directly or because the body takes them up on purpose. Gebbers and Laissue speculate that the body uses this "bacterial translocation" to learn what species of microorganisms are friendly and tolerable.

Replacement of intestinal flora
In 2007, William Parker et al. found another possible use of the appendix: to harbor enough samples of the intestinal flora to repopulate the large intestine should the patient suffer a bout of extreme diarrhea, say from cholera or amebic dysentery. Parker and his colleagues speculate that this function of the appendix might not be necessary in a highly industrialized society, where cholera and dysentery are far less common--but they also point to other studies that show that the incidence of appendicitis is far higher in industrialized countries than in non-industrialized countries. This latest finding has caused sharp debate in medical and scientific circles, especially because the appendix is found chiefly in humans, other primates, and rabbits, but not in most other mammals.

Prophylactic removal is not indicated
Mercola, commenting on the research of Parker et al. and the New York Times article reporting it, specifically condemns the removal of the appendix without a definite indication such as acute appendicitis. He points out that the removal of the appendix might increase the risk of Crohn's disease (regional enteritis). He also quotes Parker in lamenting the current state of funding availability for the type of experiment that could offer definitive proof of the usefulness of the appendix: [A]n experiment to prove this theory would be very expensive. And in any case, why would you want to spend money to find out something that is not likely to help cure a disease?

Furthermore, Mercola adds this pithy rejection of the very concept of a vestigial organ: I don’t believe human beings are born with any unnecessary parts that can be thoughtlessly removed as an aside during surgery.