It’s arguably a profound and important book in that it can change our self-perception to one that’s closer to the truth.
Putting aside some questionable attempts at humor, the core of the book is an engaging, informed Fantastic Voyage from in the mouth all the way to out the bottom. I’ve seen so many images of our digestive system but never been presented with the process as a clear narrative, with emphasis on the differences between the organs involved and the inflection points between them.
Gut
Recommended by my sister-in-common-law, a physiotherapist, I get the feeling the author was chomping at the bit to make this more comprehensive but agonized about making it entertaining. This is a mistake as anybody who wants to read this book is interested in the subject matter and doesn’t need her Germanic attempts at humor, levity, etc. What’s entertaining and great is the core of the book: an engaging, informed Fantastic Voyage from in the mouth to out the bottom. That is where it works. How many countless pictures of our digestive system have I seen, yet I’ve never had it presented as a clear narrative, with emphasis on the differences between the organs involved, and the inflection points between them.
I did not know the process of the vomit, nor that only some animals can do it (horses and rats can’t). And that the small intestine can send food back up to the stomach for vomitting, though the vomit can be just the stomach contents only.
Nor did I have any conception of the banana/dumbbell shape of the stomach, and that our smooth, involuntary muscle can stretch so much. And that the stomach is not in the pit of our bellies but higher up (though that makes sense).
But mainly perhaps it corroborated and burnished a sense that we are actually dual selves: not only does the gut have a brain but as we would perhaps expect, we are dual beings, an aware one (the brain) and an unaware one (the gut). This is vividly illustrated by the opening metaphor of the sea squirt [p114]. It is as apt as the other main metaphor, that of a tree to tell us that our visual image of it is wrong because a tree is a dumbbell, half underground – this serves to frame the explanation that as we delve into our smooth muscle organs, those involved with digestion, we lose sensory perceptions of them – we don’t even know they are there. We lose awareness of food once it leaves our throats. Meditating on this is kind of enlightening – we’d somehow expect to be more aware of something once it’s inside us.
So yes in some ways this is a profound and important book in that it can change our self-perception to one that’s closer to the truth.
All this is in Part 2, which ends with a chapter on the relationship between the gut and brain. Parts 1 and 3 lack this successful framing structure of a journey (though the tree metaphor is the beginning of Part 1).
Part 3, completely about gut flora, also has a framing metaphor, but it didn’t stick with me, even as it’s illustrated on the book’s final page: the earth at night. That’s because the section is about gut flora, which she calls “the most amazing giant forest ever”. Well, fine, but the visual image is of the earth at night, where we can only see cities, not forests. And the forest within us is confusing because we’ve already used the tree itself to describe ourselves. I suppose this can hold if we consider things holographically, but it failed for me, and so I lacked a hook on which to hold the microbe discussion, even though she tried to provide one.
No matter, the idea, the shift in perception, that we ourselves are an ecosystem, is powerful. We already knew this, but sometimes it takes some pages and pages of drumming in facts and a perspective to make us give a new perspective its due.
The illustrations loom large. They are irritating somehow, like she insisted on getting someone who insists on being unable to draw. Sure, we don’t need photorealism, but still. It’s sort of Barbapapa but unappealing.
There is so much to cover here once she opens up the topic that it feels rushed and could be 3x longer for a more comprehensive treatment. This is probably an accomplishment from her perspective, turning this topic into a popular book (though her home German audience probably needs no encouragement). For instance, “Where the ‘self’ originates” gets 2 pages.
“How the gut influences the brain” also is of great interest to me. After reading this book the thought came to me that if we are not actively remembering or doing something, we are just reflecting on how we feel, on who we are, then this is more about how the gut feels than the brain. In fact, can the brain actually feel at all? Don’t we do all our feeling in our torsos? Certainly our brain can generate ideas, thoughts, memories that can create feelings, but is that where we feel them? More than that, even when nothing’s actively going on, I know from a 50-day juice fast that you can feel like someone else when your gut feels different. I remember saying I felt like I was 8 years old. I think, more accurately, what I meant (I forget the actual feeling, this fast was a dozen years ago now) was that I feel as I felt when I was 8. Is that because I had gotten my guts to a state more akin to how they were at 8?
The gut is the largest sensory organ, she argues. Some – quite a lot – of that is sent to the brain (via the vagus nerve).
She does not mention fasting at all, which is weird. Nor mucoidal plaque, which falls out of the intestine (small?) in handfuls during a fast and creates a different feeling of selfhood (well, this seems debunked).