Honor thy Symbionts

by Jeff Leach

To paraphrase famed biologist Theodosius Dobzhansky, “nothing in nutrition and health makes sense except in the light of the gut microbiome.” In Honor Thy Symbionts, the lens of our evolutionary past is focused on modern issues of obesity, GMO foods, diabetes, the rise in C-section births, ecology of our gut microbes, our African microbial origins, government dietary recommendations, probiotics vs. prebiotics, food poisoning, and more.

This collection of 21 short essays is not organized as a single book – with a beginning and obvious end. But a collection of musings ranging from 600 to 2,000 words in length. Though a wide range of topics is covered, a microbial thread connects all of the essays. This decidedly Darwinian (evolutionary) perspective is a nod to the reality that ninety-percent of the cells in the human body are not even human, but microbial. This makes humans super organisms – however, more microbe than mammal. This biological truth is reframing the scientific and philosophical conversation around Who are we? The ultimate questions of health and disease in our modern world will hinge on the speed at which we discover and accept that we have always lived in a microbial world and much that ails us is in fact discordance with the once symbiotic relationship we coevolved with these tiniest forms of life.

Jeff Leach is the Founder of the Human Food Project.

Genres: Health, Nonfiction, Nutrition, Plants

146 pages, Kindle Edition

First published December 13, 2012

Reviews

[Stephie Williams · Rating 5 out of 5]

This book is a collection of the blog posts, mainly on the human microbiome (the bacteria itself and its genes) with some other allied posts. I believe Jeffrey Leach is a researcher scientist. Whatever his credentials, he writes well and writes for those who have some basic knowledge of biology. One area of allied posts is the damage that may occur to children born by C-section, where the baby does not go through the birth canal and fails to pick up what is thought be their first group of microbiome to populated their bodies and gives the baby a head start in fighting off some infections and helping with digestion too. This failure can also occur in those babies that are not breast fed.

His main focus is to encourage us to allow the growth of our good bacteria, which provides many health benefits. He presents a good deal of research on the microbiome that shows this. However, he is critical of some studies when it is call for. He is honest in saying that some studies, while suggestive, do not actually prove that humans would benefit from their results.

Over all, I think he does a good job in educating the reader about the bacteria that live on and in us. It does get me to think of varying the fiber in my diet, especially those that feed bacteria that digest it and makes the environment of the gut more friendlier to good bacterial growth, which among other things boosts our immune system and prevents nasty diseases, like IBS. I liked the book a lot. The book was enjoyable to read and included information I was not aware of already.

This book should be good for anyone. It will provide food for thought, that hopefully, will get you to provide the food (fiber) to your good bacteria, which do essential work for your health. I feel a little background knowledge in biology may be helpful. If your not into health or biology, I would think the only thing attractive that remains would be his good writing skills.

[Gayatri · Rating 3 out of 5]

I would give this a 3.5! It’s a worthwhile read, especially to understand what really benefits our microbiome. I do think people would need a primer though if cell cultures are not something they’re familiar with—for which I’d recommend reading the book “I Contain Multitudes: The Microbes Within Us and a Grander View of Life” beforehand.

It felt like this book could’ve been at least a third shorter because each essay/chapter started with the same framing. Could’ve saved us a lot of time. Because of that, it’s evident that each essay/chapter was a blog posts at one point.

I also do not like that there is no ethical framing around meat. The author strongly discourages dairy, yet “ethical” or “good” meat is highly recommended… along with hints that we should go paleo. Though I agree with most of the arguments for it (and yes, I’ll be incorporating much more fiber and a bit more attention towards protein into my diet), I do not believe we *need* meat—which raises the ethical question of the non-human animals whose agency and dignity we take away when eating it.

As both an academic and a nonfiction lover, there was an off-putting lack of sources. Yes, there are sources at the end of the book, but not nearly enough for the amount of claims Leach is making. How can his words be trusted?

Reading this in 2025, I do genuinely wonder if flinging knowledge like that with not-enough citations has less to the Joe-Rogan-ers and misinformation campaigns leading people to believe COVID-19 was a hoax. I genuinely wonder whether Leach is one of those people… and though I agree with most of what’s in this book, I’m also aware that that sort of thinking lacks a critical theory/justice framework that recognizes how real these problems are for underresourced individuals.

Anyway, do read the book. But keep stuff like that in mind.

[Ragna · Rating 3 out of 5]

The book seemed to be a collection of blog posts or essays, which I think are better suited for a blog than a book (others might disagree). I thought there were a few useful tips hidden in the book, but they were hidden between all the various pieces of filler that are necessary for blog posts and essays. I think they could have been edited together more cohesively.

In addition, while there was a multitude of research presented, there were also a lot of opinions by the author. This is not a problem, but it should be noted. That said, my biggest issues with the work were when the author stated something that did not feel well-thought-out. For example, he said that he hopes that those who are scared of GMOs will not be scared of plants whose microbiota have been swapped for another group. I think a statement like that should include more discussion of the risks. I don't know what they are (and if they are real), but I feel that someone who presents himself as an expert on the microbiome should accept the possibility that it might matter which microbes we consume and on what plants. I don't know, but it shouldn't be ignored. Another example is when he mentioned that he believes government policy should be used to urge people to eat healthier. The following essay told of a panel of experts who ignored what he thought to be most important, the microbiome. Why does it not occur to him that government policy would be ruled by those "experts"? He then mentioned a team of microbiome experts and implied that they would be the good experts since they do not have "a horse in the race". Believe me, if they were well accepted to be THE health experts, they would end up having horses in the race.

[BethK · Rating 4 out of 5]

Pretty good overview of what many of those trillions of microbes who make up most of what we think of as "our body" actually do for us, and how we have successfully reduced our number of them, reduced our passing them from one generation to the next, and kill them off in various ways.

I question some of the science presented, or perhaps in how it was presented. It is not clear in this book how we can return to what we used to have - for instance, even if we dropped the c-section rate to near-zero, that would not necessarily return the microbial ecology in a mother's bacteria to what her great great grandmother's was. It was made for a popular audience, not a scientific one. All in all, it was a pretty good book.

[Noel Rodriguez · Rating 5 out of 5]

An Epiphany

An insightful work that needs to be shared. I pay attention to my diet and my environment. This short book covers a great deal of ground.