Are We Too Clean?

Teeming masses of bacteria are in your mouth, on your skin, up your nose and on the surface of your eye, in your stomach, deep in your bowels, and well, just about everywhere. In fact, the number of bacterial cells you harbor exceeds the count of your own body's cells by 10 to 1.

But, as Tina Hesman Saey notes, “Don't be too hasty in reaching for the disinfectant. You can't wash these microbes away. Nor should you. They are for the most part friendly. So friendly that many scientists now view humans as conglomerate super organisms composed of thousands of species. Scientists have dubbed this internal flora the 'microbiome', a nod to the little ecosystems that have blossomed in the body throughout human evolution. These microbes are no mere hitchhikers. They're hard at work cleaning up your insides and pumping out compounds that have all kinds of effects on health, development, and perhaps even some behavior.” (1) It's starting to look like clean living is breaking up some of the healthy friendships between people and microbes, contributing to disease. Ceasing to be friends with a bacterial buddy, even one that is sometimes disruptive, can have unforeseen and potentially unpleasant side effects. (1) Truth is, we can't handle cleanliness, it's against our nature. This is the gripping focus of a recent book by Rob Dunn, a biologist at North Carolina State University, called The Wild Life of Our Bodies. (2) Over the past century, we have, driven by science and medicine, pursued an eliminationist view of health. If we purify our bodies and purge the environment of threats, we will be healthier. Obviously, this quest has been hugely successful in terms of eradicating killer diseases. Less obviously, we may have taken these interventions too far. We have neglected to find out whether our bodies, shaped by millennia to cope with nature, are able to cope when much of that nature is removed. Human survival and adaptation, explains Dunn, is not just about avoiding predators; sometimes, it is vastly more efficient, even beneficial, for a body to live and let live when it comes to parasites and microbes, reports Trevor Butterworth. (3)

---

The question is, what collateral damage have we done to our bodies through our 'kill all germs' approach to health? What co-dependent bacteria or parasites have we removed through antibiotics, medicine's equivalent of nuclear warfare? And what are the unintended consequences of the broader trend of turning humans into biological islands, remote from the nitty gritty of nature? The answer says Dunn might well be seen in rising rates of certain kinds of modern disorders—not only Crohn's disease but also allergies, immune-system problems and even anxiety disorders. Defensive systems honed by millennia to fight threats that no longer exist could now, for want of exercise, be turning on us. (2) Dunn adds, “Recent studies are unable to find any benefit to antibiotics in hand sanitizers, soaps, or other household products in terms of preventing disease. But such products do have disadvantages. They can lead to antibiotic resistance and may also be killing good bacteria if they are resistant to antibiotics.” (2) In 2010 (the latest year for which data are available), 35.1 million Americans spent at least one night in a hospital. The Centers for Disease Control and Prevention estimates that 5% of patients admitted to hospitals will acquire an infection during their stay, potentially leading to 99,000 deaths annually and costing $10 billion per year. (4) Historically, these infections have been blamed on the presence of harmful bacteria, and increasingly stringent infection-control procedures and standards for sterility have been seen as the solution. A new hypothesis says that hospital-acquired infections are being driven not by the existence of harmful microbes but by the absence of helpful species. (4) Hospital microbiomes, some researchers think, form a key part of a hospital's 'immune system' and in some cases may help protect patients against infectious diseases. (5) Human microbiome research has shown that the use of antibiotics can disrupt the normal array of microbes that live in our bodies. The constant attempts at sterilization in hospitals might function on a similar level—the use of broad-spectrum antibiotics, bleach, and hand sanitizers might take out some of the harmful pathogens, but also cut a swath through the hordes of non-pathogenic microorganisms. The elimination of these commensal microbes reduces competition, potentially making hospitals more friendly toward pathogenic species. Some sterilization efforts may not be helpful in the long run because you're going to be clearing out ecosystems which are then vulnerable to being recognized by pathogens and not just regular, boring bacteria. (4) The research is showing that the 'germs' we do our best to exterminate with antibacterial sprays are not our enemies after all. In fact, we are locked in an intimate and vital relationship with them and it shapes our physical development, helps train our immune systems and equips us with a set of metabolic abilities we would otherwise lack. Each of us is part of a vast and complex microbe-human ecosystem—less an individual that a 'super-organism'. (6) References

1. Tina Hesman Saey, “Inside job,” New Scientist, June 18, 2011, Page 26
2. Rob Dunn, The Wild Life of Our Bodies, (New York, NY, HarperCollins, 2011)
3. Trevor Butterworth, “Pure to a fault,” thedaily.com, September 12, 2011
4. Carrie Arnold, “Rethinking sterile: the hospital microbiome,” Environ. Health Perspectives: DOI:10.1289/ehp.122-A182, July 2014
5. Helena Rintala et al., “Diversity and seasonal dynamics of bacterial community in indoor environment,” BMC Microbiology, 2008, 8:56, DOI:10.1186/1471-2180-8-56
6. Claire Ainsworth, “I am legion,” New Scientist, May 2011, Page 43