The ‘Irrelevant’ Appendix

The appendix has been dubbed [as] a vestigial organ, thought to no longer perform a relevant purpose in the human body.

“Popular belief tells us the appendix is a liability,” Gabrielle Belz with Melbourne’s Walter and Eliza Hall Institute said in [the release] statement. “Its removal is one of the most common surgical procedures in Australia, with more than 70,000 operations each year. However, we may wish to rethink whether the appendix is irrelevant for our health.”

In the U.S. appendicitis will affect over 5% of the population, the National Institutes of Health stated.
Research by Belz and Eric Vivier with the Centre d’Immunologie de Marseille-Luminy in France found that the appendix might play a role in helping maintain one’s immune system with a good microbiome.

Their study, published in the journal Nature Immunology explained that a specific type of immune cell called innate lymphoid cells (ILCs), help “control the composition of the microbiota and gut immune responses.” These cells help protect against bacterial infections in people with weak immune systems, the researchers found.

And the appendix, Belz said, with protection from infection by ILCs might then “reseed ‘good’ bacteria within the microbiome – or community of bacteria – in the body.”

“A balanced microbiome is essential for recovery from bacterial threats to gut health, such as food poisoning,” she explained.



Scientists at Duke University Medical Center proposed a similar theory several years ago postulating that the beneficial bacteria in the appendix that aid digestion can ride out a bout of diarrhea that completely evacuates the intestines and emerge afterward to repopulate the gut. Their theory appears online in the Journal of Theoretical Biology.

My Take:
Surgical removal of the appendix increases the risk of all cancers tenfold. However, scientists have argued that it is invasive nature of the surgery that creates that risk, not the loss of the appendix. Either way, why not leave it in if at all possible?

There are two immune systems in the body. The acquired immune system gets all the attention from medicine. That is the system that reacts to a foreign object entering the body and creates a specific immune response to that foreign body. It is the basis of our immunization program, triggering the acquired immune system to respond to a series of injections.

The other immune system, actually the primary one, is the innate immune system. It creates a non-specific response to all invaders. The innate lymphoid cells (ILCs) of the gut are a small part of this system. Over 75% of the lymphatic system that creates these cells line the digestive tract.

As noted in this article, this theory of the role of the appendix is not new, but the discovery of the ILCs protecting the appendix is new and lends a lot of support to the theory.

The Bottom Line:
Just because we don’t understand how an organ works doesn’t mean it is useless or “vestigial”. Try to hang on to your appendix. It is often removed whenever abdominal surgery is performed, like a hysterectomy or cholecystectomy. The next step will be studies linking the health of the microbiome to the presence of an appendix.

Source: December 1, 2015 The Blaze