The Hidden Half of Nature: The Microbial Roots of Life and Health
David Montgomery and Anne Biklé
WW Norton, 2016
The authors began a journey into examining the role that microbes play in our lives by reconstituting the soil in their yard. They discovered the soil was brought back to life with relatively little effort. This lead to a lot of research into what, exactly what going on, and learning about the rhizosphere, the wealth of bacteria and microbes that surround and enrich the roots of plants. When Biklé contracted cancer, they embarked on a similar journey into the depths of the colon and the microbial life we support and which supports us. Both systems are bewilderingly complex, and there is much more cooperation and symbiosis than we thought. In both cases, a healthy microbial environment provides strength and immunity to the host (either the plant or us).
A few things prevented us from seeing these communities and benefits earlier. Our lab practices were focused on the “germ theory,” that microbes were inherently harmful and needed to be eradicated. This lead to studying only pathogenic microbes that could be easily cultured in labs. DNA sequencing allows us to study microbes that aren’t culturable outside their host environment. Further, relationships between organisms were viewed through the lens of Darwinian competition, which is only recently being challenged by new views on cooperation and symbiosis.
This is leading to a revolution in our approach to both farming and nutrition. For the second half of the 20th century, agribusiness concentrated on ever-higher doses of fertilizers and biocides for the short-term benefits of yield increase, ignoring the long-term problems of soil depletion, adaptation of pests, and destruction of helpful microbes and insects. A similar practice was happening in medicine, with a reliance on antibiotics that provided untold benefits, but which led to a larger problem we now face.
The farming practices, combined with dietary changes (and convenience foods) led to diets filled with nutritionally poor but high calorie foods. Meanwhile, our helpful gut flora were being destroyed by the antibiotics that were otherwise saving our lives. New research indicates that over-use of antibiotics is leading to both an increase in disease-resistant bacteria and chronic auto-immune and inflammation diseases.
“The Hidden Half of Nature” is filled with interesting stories about research into soil health that contradicted the agrichemical practices that was ignored, or research into gut health that went a little past the ability to visualize or quantify why things worked the way they did. One particularly fascinating story is that of Ignasz Semmelweis, who in the late 1840s noticed that the wards in his hospital run by midwives had significantly less mortality than the wards run by doctors. Why? The doctors wore their bloody coats with pride, and went between patients or autopsies and patients without washing their hands. Montgomery and Biklé say that by insisting the doctors wash their hands and change their lab coats, mortality in the doctor-run wards was reduced to the same as the midwife wards. This infuriated the doctors, Semmelweis was fired from that hospital, fired from another for instituting the same changes, and was so hounded by the medical establishment that he died in an asylum. Philosophers of science now use the term “Semmelweis reflex” to describe the autocratic rejection of new knowledge that contradicts established paradigms.
The authors are careful not to ignore the good results of agribusiness or antibiotics, but they fully acknowledge that it is crucial to adapt our practices to new realities. More careful administration of antibiotics, removing antibiotics from use as animal growth promoters, and more attention to prebiotics and foods that improve our gut flora are among their recommendations for human health. They also recommend farming practices that concentrate on soil health, such as returning stubble to the field after harvest, no-till farming, and organic farming. They acknowledge where research is still inconclusive, such as whether organically farmed plants are more nutritious than conventionally farmed plants.
“The Hidden Half of Nature” is informationally dense – the “Sources” section has pages of citations for every chapter – but is so clearly presented that at first I thought it almost felt like it was aimed at a young adult audience. Once they got onto things I didn’t know, however, I was fascinated by their stories. They mix personal experience with research in a way that brings the research into focus. The few notes are amplifications of the text that would have gotten in the way of their main point. There is also a good index.
I think this book makes a good companion to The One-Straw Revolution. Fukuoka’s book is much shorter, and focuses on his personal experience with restoring pre-agribusiness farming practices to his farm in Japan. Montgomery and Biklé present the history of the science of microbes, looking at European research into farming and medicine.