Vestigial or Vital?: Science Weighs In


If you know what the word “vestigial” means, then you likely know it has commonly applied to the appendix, an organ long deemed by medical professionals to be worse than useless. 

The prevailing theory was that the appendix had no function. However, it could occasionally suffer infection and become inflamed, causing searing pain and requiring immediate surgical removal. In fact, of the more than 300,000 American cases of appendicitis every year, between 300 and 400 people afflicted actually die from it.

Nestled snugly at the junction of the small intestine and large intestine, the organ is only 4 inches long. Shocking, considering the trouble it can cause. 

Until now, the brightest researchers in the world knew only that the appendix contained immune system tissue. Beyond that, they couldn’t name its purpose. 

But thanks to research from Bill Parker, a surgery professor at Duke University Medical School, we know the appendix performed a necessary function for our ancestors. Back when urban populations either didn’t exist (or were much thinner) and supplemental medicine had yet to be developed…

The appendix served at the pleasure of our digestive systems.

His research led scientists only a few years back to dig deeper into its function. 

The “Good Bacteria” Factory

The appendix appears, by its innate capabilities and by its placement in relation to the rest of the digestive system, to perform two imperative functions: protecting and providing healthy gut bacteria.

Bill Parker was able to support this theory through several avenues.

First of all, the location of the appendix suggests that its function is digestion-related. 

Second, because of the immune system tissue found there, the appendix would seem to be active in assisting or protecting other organs and systems. 

Parker ended up at the “good bacteria safe house” theory. 

You see, diseases like cholera and amoebic dysentery clear out all of the bacteria in the gut that not only make digestion run smoothly, but contribute to the overall health of the body. When diarrheal diseases evacuate the gut’s contents, they don’t discriminate between good bacteria and bad bacteria.

It all goes.

And the good bacteria in your gut is what makes the rest of your body run smoothly — from stabilizing your mood to bolstering your immune system.

So back before densely packed cities, coffee shops, movie theaters, and apartment buildings, people had little recourse if their gut flora died.

They needed to produce more of it and protect the good bacteria that was left, because the likelihood that they could replenish their supply by coming in contact with other people was much lower.

Under circumstances like those, the appendix was really rather valuable. After the bowels were emptied, the good bacteria in the appendix would safely emerge and restock the lining of the intestines. 

In fact, in countries with low populations and great spaces between communities, appendicitis happens with much less frequency than in highly developed nations, because they use the organ more.

But for us?

The Appendix in 1st World Countries

“Biofilm” has the strongest presence in and near the appendix. 

The bacteria living in the gut’s microbiome exists primarily in biofilm — a thin layer or microbes, mucous, and immune system tissue. 

Researchers have found that this system is valuable for more than 533 mammals. Across those species, the appendix remained part of the body throughout evolution in almost every lineage. And all of the species with appendices have immune-boosting lymphoid tissue in their intestines, which aids in healthy bacteria production.

Which would tend to suggest that those without appendices have lowered immune system function…

Interestingly, lowered immune function is also a reason that people can develop appendicitis. 

You see, in the hyper-hygienic first-world, our exposure to bacteria and viruses is much lower than elsewhere in the world — our aversion to dirt, insistence on anti-bacterial hand-washing, and dedication to sterilizing everything has also made us more susceptible to allergic reactions, asthma, and inflammation.

So although the function of the appendix (restocking our intestines with healthy gut bacteria) is no longer absolutely necessary, the body’s reaction to it begs yet another question:

Are we sanitizing our gut health away?

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