Noah Brier | May 7, 2020

Why is this interesting? - The Bacteria Edition

On microbes, health, and the unexpected usefulness of the appendix

Recommended Products

I Contain Multitudes: The Microbes Within Us and a Grander View of Life
I Contain Multitudes: The Microbes Within Us and a Grander View of Life

A book about the benefits of living with microbes and exploring the complex relationships between microbes and their hosts.

Noah here. Amongst the many things I’m skeptical of is talk of the magical power of probiotics. It’s not that I don’t believe in bacteria or the microbiome—I do and think they play a powerful role in our health and wellbeing. But I also think we aren’t quite sure how they work and, as a result, conversations having to do with the microbes in our body quickly devolve into the realm of speculation at best and pseudoscience at worst. There’s a quote from Ed Yong’s excellent book I Contain Multitudesabout the absurdity of the celebration of “good bacteria,” as an example:

Here is a strange but critical sentiment to introduce in a book about the benefits of living with microbes: there is no such thing as a “good microbe” or a “bad microbe”. These terms belong in children’s stories. They are ill-suited for describing the messy, fractious, contextual relationships of the natural world. In reality, bacteria exist along a continuum of lifestyles, between “bad” parasites and “good” mutualists. Some microbes, like Wolbachia, slide from one end of the parasite-mutualist spectrum to the other, depending on the strain, and on the host they find themselves in. But many exist at both ends of the continuum at once: the stomach bacterium Helicobacter pylori causes ulcers and stomach cancer, but also protects against oesophageal cancer – and it’s the same strains that account for both these pros and cons.

No one doubts that bacteria plays a key role in our health and digestion. There are inflammatory bowel diseases that are believed to be largely a result of a bad balance of microbes. The problem is we all have billions of these things floating around inside us and the combination is a unique fingerprint that results from a wide variety of factors. Much of the research about the effects of probiotics are inconclusive. What’s more, taking probiotics after a round of antibiotics—which many believe is a good idea—may turn out to make things worse. “A recent study by scientists at the Weizmann Institute of Science in Israel found that even among healthy people, taking probiotics after antibiotics was not harmless,” a 2018 BBC piece by Martha Henriques explains. “In fact,” the article continues, “they hampered the very recovery processes that they are commonly thought to improve.”

Why is this interesting?

One of the more fascinating ideas in the world of gut flora is that we already have a way to recover our microbiome after it’s wiped out: our appendix. A 2012 Scientific American piece outlines the theory as explained by Bill Parker, a Duke University doctor:

You may have heard the appendix is vestigial, a relic of our past like the hind leg bones of a whale. Parker heard that too, he just disagrees. Parker thinks the appendix serves as a nature reserve for beneficial bacteria in our guts. When we get a severe gut infection such as cholera (which happened often during much of our history and happens often in many regions even today), the beneficial bacteria in our gut are depleted. The appendix allows them to be restored. In essence, Parker sees the appendix as a sanctuary for our tiny mutualist friends, a place where there is always room at the inn.

If that sounds strange, it should. We’ve been told our whole life that the appendix is useless. If you’re anything like me you literally learned the word vestigial with either a point towards your tailbone or abdomen. This theory—and it’s definitely still a theory—brings into fascinating focus how much we still don’t know about our bodies. While topics like the microbiome or the genome get much of the attention, the fact that we can have an organ floating around that whose purpose we genuinely don’t know is pretty amazing. (NRB)

Podcast Episode of the Day:

A great recommendation from WITI reader AB: the Radiolab episode about the Golden Record. In addition to the content, recordings of Carl Sagan and information about the creation of the Golden Voyager record, the sound design is equally stunning. Worth your time. (CJN) 

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Thanks for reading,

Noah (NRB) & Colin (CJN)

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