Epidemic of Absence: A book that made me think too much

What it’s about:

Moises Velasquez-Manoff’s Epidemic of Absence tackles one of the trickiest and trendiest topics in 21st-century biomedical research: the complex relationship between autoimmune disease and the bacteria that live in our guts.

A growing body of evidence suggests that by decimating the number of pathogenic microbes people are exposed to, modern medicine has inadvertently shifted the ecological balance between the human immune system and the human microbiome, leaving millions of people vulnerable to allergies and autoimmune disease.

The basic evolutionary argument is that our immune system evolved to cope with a constant onslaught of opportunistic microbes by developing a complex system of checks-and-balances with our bodies’ microbial populations. With those microbes gone, many of the immune system’s coping strategies are having disastrous side effects. In this book, Velasquez-Manoff implicates the depletion of bacterial biodiversity as a driving agent in the pretty much every non-infectious disease you can think of (cancer, depression, Crohn’s, Celiac’s, allergies, and autism are all covered in this book).

The Upsides:

It’s a rare snapshot of a scientific revolution in progress. And it’s easily the most thought-provoking book I’ve read all year.

Epidemic of Absence is not a completely unbiased work, but Velasquez-Manoff is clearly a meticulous reporter with a knack for explaining scientific reasoning. (Some of the passages where he’s explaining how scientists establish causality in epidemiology are simply stellar.) Even if you don’t completely buy the thesis, you will learn a lot from this book.

The Downsides:

It’s a little bit dry and a little bit dense for a popular science book. The book is also somewhat frustrating in that it doesn’t offer very much in terms of practical suggestions for improving your health, but that’s an accurate reflection of the current state of microbiome research.

Accessible to non-scientists?

Yes. Some of the concepts may seem a little bit out-of-left field to people who haven’t taken a biology class since high school in the 1970s, and Velasquez-Manoff does assume that his reader is capable of either remembering or referring back to jargon terms that were explained in earlier pages. But you don’t need a biology degree to read it.

I’d recommend it to:

  • People who like to start arguments at dinner parties
  • People who want to learn more about microbiomes without slogging through badly-written homeopathy blogs
  • People who are curious about the causes of autoimmune disorders (and if you have an internet connection, it’s a safe bet that you or someone close to you has been negatively impacted by an autoimmune disorder.)
  • People who like to think about new ideas

My personal take:

I freakin’ loved it, but I could see why other people might not.

Epidemic of Absence that triggers more questions than it answers. It challenges our culture’s hallowed tradition of indiscriminate germophobia and leaves the reader pondering health problems (and quite possibly worrying about their children) without offering very many practical solutions. The topic definitely has the potential to make you a little paranoid, and it’s hard to know how to feel about these recent revelations…

…but that’s exactly why this book is worth reading.

Germ theory (the simple idea that microbes can cause disease) has dominated public health policy for over a century. Even now, decades after noninfectious diseases overtook infectious diseases as the leading cause(s) of death in the industrialized world, we still expect all our maladies to be solved through Koch’s postulates. When something goes wrong in human health, we ask scientists for a single, definitive cause. We want them to isolate the one bacterium or chemical agent responsible for the suffering and neutralize it.

Scientists have to isolate small parts of biological systems in order to separate correlation and causation, but that doesn’t mean that any given health problem has one single cause. Most “diseases of modernity” (cancer, heart disease, depression, etc.) have complicated prognosises and multiple triggers.  The germ theory’s “one infectious agent for one disease” model simply doesn’t fit.

And that’s where the microbiome “craze” comes in. By looking at bacterial communities as complex ecosystems, we can account for widespread and varying origins of our most intractable health problems. Epidemic of Absence is one of the first scientifically rigorous books to come out on the topic, and I think that aspect alone makes it worth reading. (Even if some critics would challenge its claim to scientific rigor.)

I was also blown away by how hard Velasquez-Manoff worked to construct and substantiate the book’s argument. There are over 40 pages of small-print notes (most of which cite specific research papers) for a 300-page text, and translational microbiology papers are not exactly easy to summarize. And he also posts long, detailed addendums to his NYT articles on his blog.

But for me the take-home message of the book was: Our habit of considering ourselves separate from the natural ecosystems is screwing us over on the physical and mental health fronts and hardly anybody has realized it yet. What’s going to happen when they do? Is microbial depletion going to become the global warming of personal health care? Are anti-vaccers going to take the argument that germs can be good and use it to further justify their selfish and idiotic actions? I personally believe that living in an industrialized country with low infant mortality and readily available treatment for most infectious diseases is worth the increased risk of developing autoimmune diseases and allergies, but will everyone feel that way?*

I read the book in fits and starts over the course of three months because each chapter gave me so much to think about. On the one hand, it’s vital that we do something to address the underlying causes behind the rising rates of allergy and autoimmune disease, but at the same time, it’s impossible to know what to do. How do we reap the benefits of commensal microbiota without inviting potentially pathogenic parasites back into our bodies? And if we do find a safe way to do that, how would we market those solutions to a public that doesn’t seem to have the attention span for thinking about scientific nuance or ecological complexity?

I don’t know, but I think more people should read this book…

*To clarify, I know autoimmune diseases cause incalculably immense amounts of human suffering, but I also believe that accommodating children with conditions like Celiac’s and Asperger’s is infinitely preferable to watching infants die of cholera.)

Scientific Key Words:

  • Microbiomes = the diverse array of bacterial ecosystems that inhabit every corner of the world, including every fold in the human body
  • Dysbiosis = ecological imbalance in a microbiome (e.g. too many colonies of a harmful or toxic bacteria or too few colonies of a beneficial bacteria)
  • Autoimmune Disease = umbrella term for syndromes where the human immune system attacks the human body. Includes asthma, allergy, arthritis, IBD, multiple sclerosis, and, according to some scientists, mood disorders like depression and anxiety.
  • Immune homeostasis = the delicate balance between commensal bacteria and the host’s immune system.
  • Hygiene hypothesis = the idea that exposure to infectious microbes during early childhood protects against allergy and autoimmune diseases later in life
  • Maternal Immune Activation hypothesis = the idea that inflammatory signals from a pregnant mother’s immune cells can predispose the gestating fetus to developing certain neurological and biological conditions (most notably Autism spectrum disorders.

tl;dr: Moises Velasquez-Manoff’s Epidemic of Absence blew my mind, and you should read it, too.

So what do you think? What’s your take on microbiomes? And what book do you think I should review next?

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