Benarde covers everything you wanted to know—and some of what you didn’t—about the interactions of humans and the microbes that live with us in this engrossing exploration of the human biome.
Noting that a normal human body of 10 trillion cells also has 100 trillion bacteria, fungi, viruses, and protozoa on and in it, microbiologist Benarde (You’ve Been Had! How the Media and Environmentalists Turned America into a Nation of Hypochondriacs, 2002) treats the human-microbial symbiosis as a (usually) harmonious “supra-organism.” The benefits we derive, he contends, are manifold: microbes in our gut help digest food and produce vitamin K; normal skin bacteria crowd out harmful pathogenic bacteria and secrete substances that kill them; gut microbes can reduce our risk of gastric and bowel cancers and enhance the effectiveness of anti-tumor agents; the species Mycobacterium vaccae appears to cure depression; exposure to a wide variety of microbes in childhood reduces the risk of allergies and autoimmune disorders. Microbes, he continues, are essential to manufacturing our major foodstuffs, from bread to beer and cheese (Limburger cheese uses bacteria normally found on our—urp!—toes); bacteria add nitrogen to soils, digest oil spills and organic pollutants, and enable raindrops to condense from clouds. Benarde also devotes much space to those few delinquent microbes that cause human illness. He traces the histories of the germ theory of disease and antibiotics, describes the deadliest pathogens, from tuberculosis to HIV, and tours frontiers of antimicrobial hygiene, from improved hospital hand-washing to the use of radiation to kill food pathogens. The book sometimes meanders too much, but the author brings together a wealth of scientific lore in prose that’s interesting, accessible, and studded with entertaining historical anecdotes. His enthusiasm for the subject is, er, infectious—“Is that a hellofa jarring thought?” he muses about statistics indicating that we are “more microbial than human”—and he mounts impassioned arguments on policy issues, including stinging attacks on opponents of genetically modified foods and childhood vaccinations. The result is a thought-provoking reconsideration of our relationship with nature at the most intimate level.An occasionally icky but always fascinating guide to the ecosystem within.