5 Books to Introduce You to Your Gut Microbiota

5.) The Wild Life of Our Bodies by Rob Dunn: This book takes a broad look at the role that hangers-on have on  human life.


4.) The Psychobiotic Revolution by Scott C. Anderson et. al.: This book focuses on the role that our gut microbiota have on our mental well-being–which increasingly appears to be substantial.


3.) Missing Microbes by Martin J. Blaser: The focus of this book is on how our love of antibiotics in every form– from pills to antimicrobial soaps–is killing us by denying us microbiotic diversity and robustness.


2.) 10% Human by Alanna Collen: Collen’s book addresses many of the same issues as the other books mentioned, but–as the title suggests–it emphasizes the fact that a human has 10 times as many hangers-on of other species as it does cells that are contiguous to the body. (If you’re wondering how this could be, it’s because the human body has some pretty big cells [some macroscopic, in fact] and the bacteria and other single-celled species tend to be relatively tiny.)


1.) I Contain Multitudes by Ed Young: This is probably the most highly-regarded of the books on this subject. It was considered one of the best science books of 2016.

BOOK REVIEW: The Wild Life of Our Bodies by Rob Dunn

The Wild Life of Our Bodies: Predators, Parasites, and Partners That Shape Who We Are TodayThe Wild Life of Our Bodies: Predators, Parasites, and Partners That Shape Who We Are Today by Rob Dunn

My rating: 4 of 5 stars

Amazon page

Dunn’s book addresses a host of intriguing questions such as:

-Why are there diseases that disproportionately attack those in the richest parts of the world while being almost non-existent in poor countries?
-Why is obesity at epidemic proportions among modern humans?
-Why—while people have diverse tastes overall—do there seem to be universal preferences for sweet, salty, and fatty foods?
-Why are so many people’s lives wrecked by constant stress and worry?
-Is the Appendix really a vestigial organ with no apparent purpose?

As the subtitle suggests, this book is about the role that other species have played in human evolution and the way we look, behave, and think today. The message of The Wild Life of Our Bodies is that humanity’s proclivity to see itself as an island–uninfluenced by other species–has its cost.

The book is popular science–approachable to a layman but with the usual disdain for gratuitous assertions and shoddy reasoning that define the scientific though process. That being said, Dunn does put some editorial opinion out there in ways that might appear as fact in a slipshod reading. The most prominent example being Dunn’s suggesting that what best defines humanity is not our intelligence or ability for abstract representation (or even our physical appearance), but that we are the only (first?) species that has killed other species off not purely of self-defense or for food, but to exercise control over our ecosystem. I doubt this would strike a majority of impartial scientists as a fair and unbiased way to define humanity. Granted, this point not what The Wild Life of Our Bodies is about, and whether one thinks this it is fair or not is not critical to whether one will find the book to be of value. However, the idea (and the fact) that humans have zealously killed off other creatures is certainly relevant to the discussion at hand.

If “terraforming” is the term for how an alien race might environmentally engineer Earth to make it suitable for them to live here, perhaps we could call humanity’s assault on other species “bio-forming” of the planet—choosing a roster of species that strikes our fancy. All the time humans were trying to make ourselves more comfortable by getting rid of inconvenient species, we remained ignorant to the downside.

Dunn covers a broad range of mismatches between who we are evolutionarily and how we live in the modern world. The Wild Life of Our Bodies suggests that, like the pronghorn antelope, humans are in many cases over-designed because of the loss of species (parasites, predators, symbiotes, etc.) that helped to make us who we are today. (One question that once puzzled biologists was why pronghorns were so much faster than every species they faced.)

While it sounds good to be over-designed (at least relative to the alternative), it’s not without cost. In our case, we had guts that were supremely adapted to having parasites, but the lightning fast (on an evolutionary timescale) elimination of those parasites has left us with bodies that attack a non-existent enemy and this has resulted in a number of new diseases. We are used to diseases that succeed in the poorest—and, hence, least hygienic areas– but disease that mostly attacked in the cleanest places on Earth have puzzled us for some time. Crohn’s disease is a prime example. “Rewilding” (i.e. putting parasites back into) the guts of Crohn’s patients has shown positive results.

Dunn lays out a couple of the theories as to how the loss of our intestinal bacteria may result in a number of first-world ailments. Interestingly, some of these diseases aren’t even digestive in nature, and might seem to have no logical connection to gut bacteria. However, our body’s systems are a system-of-systems—i.e. they are integrally linked. One issue is that some parasites have been able to mask their presence, and our bodies have learned to present a heightened response to account for this veiled threat. Today our systems can’t tell the difference between our squeaky clean guts and a gut full of these sneaking parasites so it drops the immune system version of an A-bomb.

This is one example of why some diseases don’t exist in the third-world where the body knows what parasites it’s up against. One might say, “Yes, but these ailments of over-reactive systems can’t be as bad as the effects of the parasites.” That’s often not true. Most people with internal bugs (we all have them to some degree), don’t even realize it. The fact that people with Crohns’ are willing to have predators implanted in them speaks to this issue.

There has been concern for years about downside of the rampant use of anti-bacterials, antibiotics, and antiseptics, and this is a topic Dunn addresses as well. For example, there seems to be little evidence that such agents in soap do any particular good, but they decidedly do bad (encouraging drug resistant species.)

Perhaps the single greatest change in the nature of homo sapiens life resulted from the agricultural revolution, and Dunn delves into how this seminal event changed our bodies. With paleo-dieting all the rage, it will come as no surprise that there have been some major changes to the human diet since our hunter-gatherer ancestors roamed the Earth. Once again, we have bodies built on an evolutionary timescale, and they don’t necessarily cope well with our new diets.

One problem is that we have strong hardwired drives for foods that were a rarity in our species’ past, but which we now produce in abundance. For example, we eat far too much refined sugar because our bodies are wired to love sweet, but that kind of food was rare to our pre-agricultural ancestors. Hence we have the existence of diabetes, and its greater prevalence where high-sugar diets are common. Many people are also saddled with an evolutionary advantage to store fat because their ancestors come from a clime where food was not abundant year round. The problem is that now there’s a grocery store on every corner and this once great advantage is contributing to burgeoning waistlines.

I gave this book a high rating on the grounds that it presented a lot of food for thought, and that’s what I most value in non-fiction. Some of the theories may turn out to be incorrect, but this book offers one a lot to think about and clear explanations of the bases for what can otherwise seem a little outlandish. There is also some wit in places that contributes to heightened readability.

View all my reviews

Antifragility and First World Diseases


TheWildLifeofOurBodiesI was sitting at an outdoor cafe as I thought about how to write this post. I’d just finished reading chapter 5 of the Rob Dunn book entitled The Wild Life of Our Bodiesand was reflecting upon how interesting it was to be reading two books whose central premise–in broad brush strokes–was the same. As I was ruminating, a family of four–a couple and their two daughters, an infant and a preschooler/kindergartener–came and sat down at an adjacent table.

For a while the preternaturally-cute infant crawled around on the table top, but as the mother became concerned that the wriggly little child might fall or spill scalding coffee, she eventually set the child down. The child proceeded to crawl around on the ground–ground on which one could easily imagine pigeons trolling for crumbs. [Full-disclosure: I didn’t actually see any pigeons, or even any noticeable filth on the ground for that matter, and–while this is India–it was a major coffee chain attached to the side of a popular up-scale shopping mall, and so that particular ground was probably at least hosed down daily.] The child crawled on all-fours, except that she had the plastic number placard which told the waitress where to bring the order in one of her hands, and she would alternate between dragging it across the ground and–when she got tired of crawling–she would roll onto her rump and pop a corner of the placard into her mouth.

If reading the preceding scene made you a bit queasy, you should be reading one [or both] of books mentioned above. Doing so gave me a totally different perspective on this event. There was a point when I–like many–would have assumed the little girl would get some sort of ailment and that her parents would pay in lost sleep for letting the kid crawl on the ground in an urban public space, but I’m now more inclined to think that probably nothing will happen, and she could–theoretically–end up better off for the wear. I’m not advocating wallowing in filth, but I have come to see biological stressors in a new light. I wouldn’t go so far as to advocate letting a child crawl around sticking things in his or her mouth that have been on the ground at a cafe, but it would no longer surprise me to hear that this child lived a healthier life than children of germophobic (properly “mysophobic”) first-world moms who are about one cookie-off-the-kitchen-floor from forcing their children to live in a bubble.

The reader may be wondering two things: 1.) how these books could mitigate one’s queasiness, and 2.) what the books even have in common. If  you’re familiar with Nassim Nicholas Taleb, it’s likely you associate him with criticisms of the misuse of statistical methods, and the failure to understand under what conditions the usefulness of these methods break down. While Taleb does consider a wide range of examples in his popular books Black Swan,  Fooled by Randomness, and–most recently and most relevantly–Antifragilethe world of business is where Taleb’s background lies and where much of his discussion is centered. The Dunn book, one the other hand, fits squarely in the domain of biology and medicine.

Both of these books take as their core idea that there are systems that must face constant and occasionally serious challenges to grow stronger, and that the removal of these challenges can have adverse and sometimes dire consequences. Taleb looks at such systems in a broad and general sense, and coins a term, “antifragile”, to describe such systems. A system is antifragile if it gets stronger (i.e. in some way better) when subjected to stresses. This shouldn’t be confused with robustness, which is being indifferent to stressors. Robust systems can take or leave stressors, but antifragile systems need them or they become weakened. Dunn’s book deals with a specific example of an antifragile system, our guts. The biologist suggests that our war on parasites and germs has created a whole raft of problems never before seen. It’s probably not a new idea to most readers, as there are ongoing arguments about the risks of our antibacterial frenzy.

While first-world dwellers tend to take a superior view of those poor third-worlders and their myriad ailments–a number of which have been stamped out in the developed world–Westerners may not even be aware that there are a number of ailments that exist almost exclusively in the first world. Increasing evidence is developing that certain forms of diabetes and allergies are linked to “clean living.”  Interestingly, while one might readily imagine how a digestive tract ailment like Crohn’s Disease is tied to insufficiently populated digestive ecosystem, there’s reason to believe that diverse issues such as autism and anxiety disorders may also be linked to loss of internal predators and the imbalances their loss causes.

It’s not entirely a coincidence that I’m reading these books concurrently. I’ve been interested in the issue in a broad sense as of late. How does the craving of comfort weaken a population? What are the risks of indiscriminately weeding the stressors out of one’s life? (As seems to be a major objective of modernity.)  Of course, stressors are not eliminated, but instead stressors that are relatively feeble may become the 800 lb. gorilla of stressors.