more on the microbiome -- 8/11/14
Today's selection - from Missing Microbes by Martin J. Blaser, MD. Blaser, former chair of medicine at NYU and president of the Infectious Diseases Society of America, is one of a growing number of medical practitioners and researchers who believe that we are experiencing a growing array of "modern plagues," and that the cause of these plagues is rooted in our "disappearing microbiota":
"Within the past few decades, amid all of [our] medical advances, something has gone terribly wrong. In many different ways we appear to be getting sicker. You can see the headlines every day. We are suffering from a mysterious array of what I call 'modern plagues': obesity, childhood diabetes, asthma, hay fever, food allergies, esophageal reflux and cancer, celiac disease, Crohn's disease, ulcerative colitis, autism, eczema. In all likelihood you or someone in your family or someone you know is afflicted. Unlike most lethal plagues of the past that struck relatively fast and hard, these are chronic conditions that diminish and degrade their victims' quality of life for decades. ...
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"The autoimmune form of diabetes that begins in childhood and requires insulin injections (juvenile or Type I diabetes) has been doubling in incidence about every twenty years across the industrialized world. In Finland, where record keeping is meticulous, the incidence has risen 550 percent since 1950. ... But the disease itself has not changed; something in us has changed. Type I diabetes is also striking younger children. The average age of diagnosis used to be about nine. Now it is around six, and some children are becoming diabetic when they are three.
"The recent rise in asthma, a chronic inflammation of the airways, is similarly alarming. One in twelve people (about 25 million or 8 percent of the U.S. population) had asthma in 2009, compared with one in fourteen a decade earlier. Ten percent of American children suffer wheezing, breathlessness, chest tightness, and coughing; black children have it worst: one in six has the disease. Their rate increased by 50 percent from 2001 through 2009. But the rise in asthma has not spared any ethnicity: the rates were initially different in various groups, and all have been rising. ... No economic or social class has been spared.
"Food allergies are everywhere. A generation ago, peanut allergies were extremely rare. ... Ten percent of children suffer from hay fever. Eczema, a chronic skin inflammation, affects more than 15 percent of children and 2 percent of adults in the United States. In industrialized nations, the number of kids with eczema has tripled in the past thirty years. ...
"Why are all of these maladies rapidly rising at the same time across the developed world and spilling over into the developing world as it becomes more Westernized? Can it be a mere coincidence? If there are ten of these modern plagues, are there ten separate causes? That seems unlikely.
"Or could there be one underlying cause fueling all these parallel increases? A single cause is easier to grasp; it is simpler, more parsimonious. But what cause could be grand enough to encompass asthma, obesity, esophageal reflux, juvenile diabetes, and allergies to specific foods, among all of the others? Eating too many calories could explain obesity but not asthma; many of the children who suffer from asthma are slim. Air pollution could explain asthma but not food allergies. ...
"The most popular explanation for the rise in childhood illness is the so-called hygiene hypothesis. The idea is that modern plagues are happening because we have made our world too clean. The result is that our children's immune systems have become quiescent and are therefore prone to false alarms and friendly fire. ...
"We need to look closely at the microorganisms that make a living in and on our bodies, massive assemblages of competing and cooperating microbes known collectively as the microbiome. ... Each of us hosts a ... diverse ecology of microbes that has coevolved with our species over millennia. They thrive in the mouth, gut, nasal passages, ear canal, and on the skin. In women, they coat the vagina. The microbes that constitute your microbiome are generally acquired early in life; surprisingly, by the age of three, the populations within children resemble those of adults. Together, they play a critical role in your immunity as well as your ability to combat disease. In short, it is your microbiome that keeps you healthy. And parts of it are disappearing.
"The reasons for this disaster are all around you, including overuse of antibiotics in humans and animals, Cesarean sections, and the widespread use of sanitizers and antiseptics, to name just a few. ...
"The loss of diversity within our microbiome is far more pernicious [than the overuse of antibiotics and resulting antibiotic resistance]. Its loss changes development itself, affecting our metabolism, immunity, and cognition.
"I have called this process the 'disappearing microbiota.' It's a funny term that does not immediately roll off your tongue, but I believe it is correct. For a number of reasons, we are losing our ancient microbes. This quandary is the central theme of this book. The loss of microbial diversity on and within our bodies is exacting a terrible price. I predict it will be worse in the future. Just as the internal combustion engine, the splitting of the atom, and pesticides all have had unanticipated effects, so too does the abuse of antibiotics and other medical or quasi-medical practices (e.g., sanitizer use).
"An even worse scenario is headed our way if we don't change our behavior. It is one so bleak, like a blizzard roaring over a frozen landscape, that I call it 'antibiotic winter.'"
|Martin J. Blaser|
|Missing Microbes: How the Overuse of Antibiotics Is Fueling Our Modern Plagues|
|Henry Holt and Company, LLC|
|Copyright 2014 by Martin J. Blaser|