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Symprove Book Reviews: Follow Your Gut & I contain Multitudes

The Symprove Book Review articles are being introduced to provide some insight and recommendations for books that cover different aspects of the microbiome. 

Books are selected to allow for different levels of knowledge or detail as well as available reading time.

In this first review we have selected two books that provide overviews of the microbiome, with particular focus on the gut microbiome.  Both are readily available from a range of different stockists.


 1. Follow Your Gut: The Enormous Impact of Tiny Microbes. Knight, R. and Buhler, B. (2015)

Follow your Gut, published as a Ted book in 2015, is a short read that provides an overview of microbes, the human microbiome and its role in health.  It is a perfect introduction to the subject for those who are just beginning to hear, read or become curious about the world within us.  It would also be a suitable read for interested lay people.

An easy read for a spare hour, the contents are well laid out with explanations of the microbial communities that exist in humans, how we acquire our microbiomes, what influences them and their potential roles in health and disease.  The style is chatty, with many personal examples and comparisons included to illustrate points raised, which contribute to make the book such an accessible read.  Examples of research or experiments are varied; some are presented anecdotally, such as that in which the author and a colleague matched subjects to their computer mouse on the basis of their palm microbiome alone with a 90% accuracy.   Other sections, such as that on the gut-brain axis, are firmly based on published research.  A full list of references, for each chapter and annex, is included for those who wish to dive deeper into the science behind our microbiome.

The author is a professor as well as the Director of the Microbiome Initiative at the University of California.  In 2012 he co-founded the American Gut project, a crowd-funded citizen project that aims to build a database of the gut microbiome of individual people – in the USA and beyond – with the purpose of that data being available for analysis and research, thus furthering our understanding of the human microbiome.

 2. I contain Multitudes; the microbes within us and a grander view of life. by Ed Yong, first published in 2016.

A book for anyone who wishes to be made to challenge the way they think about microbes and can take the time to dip in and out of the detail it presents. 

I contain Multitudes explores the world of microbes in the environment, in animals and in us.  The author, Ed Yong, particularly looks at the symbiotic relationships that exist between microbes and animals and how these may have occurred, the potential benefits they bring and the way in which microbes can affect evolution. 

There is an interesting section on milk, exploring the importance of human milk oligosaccharides produced by human mothers in large numbers but which are not digestible by babies.  This may appear wasteful.  However, these HMO substances are metabolised in the colon by specific bacteria, releasing substances that nourish the infant’s gut cells and contribute to the maturation of the baby’s immune system. 

Beyond babies, the book looks at links between disease and the microbiome, including a section on IBD.  Yong highlights the complexity of this condition, in which the gut microbiome plays a role, alongside multiple other factors such as genetic predisposition, immune problems and exposure to viruses or toxins.  Probing deeper into gut microbiome dysbiosis leads to a further discussion on diet, particularly fibre and plant consumption.

There are many examples of bacteria in insects and animals having a role in their hosts survival and ability to adjust to their environment, so that they can exist in ecologically specialised areas that would otherwise be inaccessible, intolerable or offering a diet that would be indigestible.  An extensive bibliography provides opportunity for further reading. 

The book leads readers to consider the world and its inhabitants very differently, with each animal or human being a community in its own right and every building and surface an entity teaming with invisible life.  The essential role of microbes in the survival of more developed life forms comes across very clearly and perhaps will lead to a more balanced view of the need for microbes as essential partners in life, rather than just illness-causing pathogens.

The author, Ed Yong, is an award-winning Anglo-American science writer.

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