10% human book coverReviewed by Alyssa Katanic

In recent years we have learned that antibacterial soaps are bad for us and that hand sanitizers contain triclosan. So, we have found “natural” ways to kill these germs: cloths laced with silver, essential oils promising to kill bacteria and other microbes, but what if not all microbes are our enemies? What if our health and sanity are dependent on these microbes that we kill off every day? In her new book, 10% Human: How Your Body’s Microbes Hold the Key to Health and Happiness, evolutionary biologist Dr. Alanna Collen explores just that and explains that the cells that make up our bodies and help us to function are not 100% human cells. In fact, our bodies are merely 10% human.

By hitting on health concerns that seem new to those of us in 20th century western culture, such as obesity, autism, type 1 diabetes, and Irritable Bowel Syndrome, to name a few, Collen describes the coexistence and co-dependent relationship that we share with our microbes, their effect upon our weight, immune system, behavior, and our battles with a myriad of inflammatory related diseases. Collen points out that the areas of the world most affected by such diseases are also those which have been the most sanitized, and overwhelmed by antibiotics in both the medical world and within agricultural industries.

Collen is very balanced in regards to the fad diets and health trends that we like to get into, such as gluten and dairy intolerances, leaky gut syndrome, grain free and high protein diets, and the like. She looks at many of them in a very detached way: what are the benefits, are there any pitfalls? She gives a very realistic look at all of these things and brings it back down to earth. Yes, there are some good and bad points in all of the things that we do as far as diet and such, but it all comes back to what is living in our guts. Who are we feeding besides ourselves, and, in turn, who is feeding us? Our microbes are not just parasites hitching a ride for themselves. They work for us, so, she concludes, we need to work for them. We need to feed them healthfully, to take care of them and to make sure that we are not constantly trying to kill them off with a spray of antibacterial cleaning mist here and a squirt of hand sanitizer there, or another round of unnecessary antibiotics. We need to safeguard the little guys who help us through everyday, as they not only aide us in digestion and immunities, but also put forth chemicals that prompt our bodies to grow and to behave in specific ways. It is fascinating…and kinda creepy!

Where does Collen get her information? She is a PhD in evolutionary biology who, during her work in the jungles, picked up some tics, and the lyme disease they carry, which wreaked havoc on her own system due to the necessary dose, after dose, after dose of antibiotics that saved her life and weakened her microbiome. Thus, she has learned first hand, as well as through research, the help and hurt of antibiotic use, and the process of recovering the good bacteria that was killed off in the crossfire. She is not just coming at the topic of microbial health from a researcher’s point of view, but also as an everyday woman who is fighting to recover a healthy microbiome for herself and her own family. Oh, and, just in case you missed it, she restates her evolutionary stand on nearly every page, explaining how she believes that we have evolved into such a dependent relationship with the microbes which live in, on, and all around us, and what that may mean as microbes continue to evolve with each dose of antibiotics that is prescribed.

Despite the heavy science and the medical topic and language throughout 10% Human, Collen does add a bit of her own humorous personality throughout the book to make it a little more readable. That said, there will still be some vocabulary that may have you looking things up. It may also take some time and practice to get to know all of the different microbes that she speaks of and what job they do for or against us, but it is still very interesting to try to figure things out! If the scientific language doesn’t have you asking Siri what a specific word means, her use of British, not American, English just might. For instance, just so you don’t have to look it up like I did (Thank you, Siri, for your help!), a “stone” is equal to about 14 pounds in weight.

10% Human by Alanna Collen will amaze you as you realize what a biosphere your body is for the microbes that live there. You may have a few “Aha!” moments when considering your own health, or that of a family member, in relation to the antibiotics and antibacterial products you have used. You will also learn a few things you can do to support and encourage the growth of your good bacteria, and how to pass your good microbes on to others – especially you moms and moms-to-be. If you are interested in diet and health type reads at all, I highly suggest 10% Human.

Rating: ★★★★★ 

Alyssa Katanic is a wife and homeschooling mother of 7 children under 11 years old. She loves reading and collecting great books to share with others and knows that one can never have too many!

Review copy was provided free of any obligation by Harper. No monetary or any other form of compensation was received.