Writing in the March-April issue of the Saturday Evening Post, science writer Sharon Begley explains how our overzealous use of anti-microbial home and personal cleaning products, coupled with our overuse of antibiotics, may be making us less rather than more healthy.
It’s a good reminder that sometimes we let disease mongering — often by companies trying to sell us their products — get the better of us.
A profusion of research in just the past five years is showing that our microbial hitchhikers, collectively called the “human microbiota” and so small they account for only 1 or 2 percent of our weight, play a key role in maintaining our health. And we disrupt them at our peril. “It’s not possible to understand human health and disease without exploring the massive community of microorganisms we carry around with us,” says Professor George Weinstock of Washington University in St. Louis. Knowing which microbes live in healthy people “allows us to better investigate what goes awry in diseases that are thought to have a microbial link, like Crohn’s and obesity.”
The microbes in our body — especially some of the 10,000 or so species of bacteria in and on us — have indeed been implicated in disorders as diverse as obesity and Crohn’s, and also in asthma, heart disease, sinusitis, and possibly even mood disorders. They influence how big our appetite is and, possibly, even what foods we crave. They synthesize vitamins and affect how quickly we metabolize drugs such as acetaminophen (Tylenol), they protect against esophageal reflux and they churn out many of the same neurochemicals as our own brains. Given this job description, it’s hardly surprising that when perturbed, scientists are discovering, the microbiota can tip us into poor health or outright illness.
Exactly how our bacterial companions affect our health is the subject of ongoing research in labs around the world, but one thing is clear: Our decades-long war on germs is looking seriously wrongheaded. In an effort to obliterate disease-causing microbes through antibiotics and anti-microbials — from the pills we down for a cold (against which antibiotics are useless) to the meat we eat to the hand-sanitizer-dispensers everywhere you look — we are carpet-bombing our microbiota. And that war on germs takes a huge toll on beneficial bugs, too.
Begley uses the bacterium Helicobacter pylori, which causes ulcers and has been linked to stomach cancer, as an example of how our war on germs can have unintended consequences:
Although it was once in almost everyone’s gut, it is now found in just 6 percent of U.S. children, Science magazine reported in 2011, probably due to the widespread use of antibiotics and anti-microbials. That should mean fewer ulcers, but there’s a dark lining to that silver cloud: H. pylori may ward off asthma. Scientists led by Dr. Martin Blaser of New York University Langone Medical Center found that those without H. pylori are more likely to have had childhood asthma than those with it. Coincidence? In 2011 scientists in Switzerland infected half of a colony of mice with the bacteria and left the other half germ-free. They showered all the mice with dust mites and other allergens. Mice with H. pylori were fine; those without suffered airway inflammation, the hallmark of asthma.
In the article, Begley describes other research into how microbiota influences health and disease, including how its imbalance may play a role in chronic sinusitis, rheumatoid arthritis, atherosclerosis and obesity.
“Where all this leaves someone who wants to cultivate healthy microbiota is only starting to become clear,” she adds. “… experts say it pays to heed the advice of mainstream medical groups, which recommend restricting the use of antibiotics to only must-have circumstances, not every cough and sniffle. Consider buying antibiotic-free meat.”
And “be wary of manufacturers making exaggerated claims about probiotics and prebiotics,” she adds.
That’s an important warning. The claim that probiotics can replenish your gut with good bacteria and thus improve digestive health has some decent science to support it, but other health claims are mostly just marketing hype — in a way, another form of disease mongering. (Pro-probiotic studies are often funded by the companies that make the products.)
You can read Begley’s article in full on the Saturday Evening Post website.