Microbes are having a moment. While the germ theory of disease has been around since the 16th century, scientists have come to appreciate the health benefits of bacteria and other microorganisms only recently. The development of fecal transplant therapy, primarily at MIT (the nation's first stool bank is in Cambridge), the popularity of probiotic supplements, and the establishment of the National Institute of Health's Human Microbiome Project in 2008 all attest to our growing realization that certain infections are actually good for us.
David R. Montgomery and Anne Biklé, authors of "The Hidden Half of Nature: The Microbial Roots of Life and Health," became interested in the positive attributes of microorganisms several years ago when they moved into their home in Seattle. Their garden thrived after Biklé, an environmental planner, added leaves, sacks of discarded coffee grounds from Starbucks, animal feces from the local zoo, and other microbe-rich material to the poor soil. Montgomery, a geomorphologist at the University of Washington, was impressed. "The soil was thicker and darker," he said in a phone interview with the couple. "It was changing right in front of my eyes. I was working on the problems of soil degradation and erosion and I thought: Anne is doing the reverse, right here in our backyard!"
When Biklé was diagnosed with cancer in 2011, the couple's respect for microbes grew. After surgery, Biklé improved her diet, replacing daily lattes and scones with fruits and vegetables. Plant-based eating is healthier, Biklé learned, not only because it offers more vitamins, minerals, and fiber, but because fruits and vegetables encourage bacterial growth in the gut that, in turn, supports the immune system. "We are not what we eat — we're what our gut microbiota eats," Biklé said. "Most of us think our colon is some kind of on-board garbage can. It's much more like a medicine chest that our diet can help us stock."
Montgomery believes that people might find it easier to adhere to a plant-based diet if they better understood the connection between microorganisms and health. Doctors told him for years that he should be eating more healthfully, but he didn't change his habits until he started studying microbes. In restaurants, he now chooses salads more often than cheeseburgers, because he knows his gut bacteria "need care and feeding."
Biklé hopes that new research into the microbiome will lead to changes in both medicine and agriculture. Overuse of antibiotics in livestock and in humans and even ubiquitous hand sanitizer are killing bacteria that could benefit humans, animals, and plants. She said she can sum up the couple's message in six words: "Mulch your soil, inside and out."