I Contain Multitudes

Science is a way of life. From our first observations as curious three-year-olds we are scientists-in-the-making. Science drives our understanding of the world around us. It helps us at the doctor’s, with our shopping habits, to make our gardens more productive, our cooking better, to understand disease, health, relationships, and motivations. I can’t imagine life without science – well I can, but it’s a world I wouldn’t want to live in. What I appreciate most, besides an ever-increasing understanding of the world, is that good science leads to more questions.

What I write on this blog is an attempt to understand the world right in my own backyard. What tangled webs of life cycles exist and why, and how I can protect and enhance the nature already here. Knowing the squirrels, turkey vultures, opossums, black snakes, dandelions, screech owls, snapping turtles, deer, hoverflies, and others I’ve written about enriches my world, grounds me and fills me with more questions. Science is like a continuous enrichment machine; all you have to do is dive in.

So how could I not dive in when I saw the title for Ed Yong’s latest book, I Contain Multitudes: The Microbes Within Us and a Grander View of Life. I already knew that microbes were way more important than most give them credit for, that they are helpful, not just harmful. But having just finished this book, I can agree with other comments about it such as, “It will change who you think you are.”

Yong states that I’m not just a person, a body, or a vessel with my own DNA. I’m not an island in a sea of other organisms. I am a sea of organisms in constant contact with other seas of organisms. Bacteria with their own DNA, helping me, hopefully, but I’m sure not always, in my pursuit of growth and happiness. They after all, have an agenda also – to survive and replicate – but since I’m a relatively healthy and happy 51-year-old, I think the symbiosis is working fairly well. Question: Could it be better?

The bacteria living in and on my body is different than the bacteria living in and on your body. Even the bacteria living on my left hand is a different population than those on my right hand. All living organisms have their own microbiome signature. More mobile organisms like us humans spread ours around wherever we go. While our knowledge of all the symbiotic relationships out there is in its infancy, and questions of self-improvement through microbiome manipulation are still being tested, it is apparent that diversity in our microbiome is paramount to better health.

Diversity in your home: bringing a pet in to live with your family increases the microbial diversity of the home and trains immune systems of young children. Dog dust has been found to have allergy-suppressing microbes (Yong, p. 252).

Diversity in our hospitals: scientists have found that the air inside air-conditioned hospital rooms is not a subset of the outside air. The air outside was a “full of harmless microbes from plants and soils. Indoors, it contained a disproportionate number of potential pathogens, which are normally rare or absent in the outside world, but had been launched from the mouths and skins of hospital residents. The patients were effectively stewing in their own microbial juices. And the best way of fixing that was remarkably simple: open a window” (Yong, p. 257). Question: does a health care worker bring home a diversity of microbes that helps the others at home (like a pet does) or is it a negative addition to the home’s microbiome?

 Diversity based on lifestyle: scientists compared the microbiomes of people in WEIRD countries (Western, Educated, Industrialized, Rich and Democratic) with those of rural communities and from hunter-gatherer societies. “All of these groups still live traditional lifestyles. They find or catch all of their food. They are rarely, if ever, exposed to modern medicine. They are still modern people with modern microbes living in today’s world, but they at least hint at what microbiomes look like without all the trappings of industrialised life” (Yong, p.131). Yong goes on to say that the data show that all these people’s microbiomes are more diverse than those in the West. “Their multitudes are more multitudinous.” One example is a strain of bacteria that helps digest carbohydrates. It is present in hunter-gatherers and apes and absent in industrialized populations. Question: can we choose certain foods to augment our microbiome?

 Our diversity is in constant flux: Yong explains, “The microbiome is not a constant entity. It is a teeming collection of thousands of species, all constantly competing with one another, negotiating with their host, evolving, changing. It wavers and pulses over a 24-hour cycle, so that some species are more common in the day while others rise at night. Your genome is almost certainly the same as it was last year, but your microbiome has shifted since your last meal or sunrise” (Yong, p.136). Question: how does my particular microbiome shift and what habits could I have to increase my vitality?

Many of the models we are working with to stay healthy, grow stronger, etc. appear to be incorrect. I’m excited about this grand view of life we’re learning from the smallest organisms on the planet. Bacteria aren’t just hanging out with us or hitching a ride, they’re integral to who we are. They’re integral to all life processes on earth. The bolded sentences above are just some of the many questions I had reading this book. I highly recommend I Contain Multitudes as a way to start your year, a way to rekindle your three-year-old scientist. The book is not laden with confusing terms; it’s quite readable, and Yong’s sense of humor adds to the experience. I really do see myself differently. In this essay I highlighted examples that largely affect humans, but much of the first part of the book highlights what we know about microbial processes that affect plants and animals. I know my walks at Halcyon will be enlightened with this new knowledge.

So I hope you’ll check out I Contain Multitudes. At the least you’ll have the latest understandings of microbial processes and their effects on human life. At best your worldview will be changed. Happy New Year! Life is much more fun when you’re curious. I for one will be looking at even the common dandelion at Halcyon differently from now on.

2 thoughts on “I Contain Multitudes”

  1. Really nice post, Lisa. I’ve been interested this subject for a while and will look for the book. I’m specifically interested in the strain of bacteria found in hunter-gatherers but missing in us that helps digest carbs.


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