Caution: Killing Germs May Be Hazardous to Your Health
Posted: Mon Oct 22, 2007 6:38 am
http://www.newsweek.com/id/57368
Exerpts:
In terms of infectious disease, the environment of the American suburb is unquestionably a far healthier place than most of the rest of the world. But we've made a Faustian bargain with our antibiotics, because most researchers now believe that our supersanitized world exacts a unique price in allergies, asthma and autoimmune diseases, most of which were unknown to our ancestors. Sachs warns that many people drew precisely the wrong conclusion from this, that contracting a lot of diseases in childhood is somehow beneficial. What we need is more exposure to the good microbes, and the job of medicine in the years to come will be sorting out the good microbes from the bad.
And that's an essential step in the development of a healthy immune system. The immune reaction relies on a network of positive and negative feedback loops, poised on a knife edge between the dangers of ignoring a deadly invader and over-reacting to a harmless stimulus. But to develop properly it must be exposed to a wide range of harmless microbes early in life. This was the normal condition of most human infants until a few generations ago. Cover the dirt on the floor of the hut, banish the farm animals to a distant feedlot, treat an ear infection with penicillin, and the inflammation-calming interleukin-10 reaction may fail to develop properly. "Modern sanitation is a good thing, and pavement is a good thing," says Sachs, "but they keep kids at a distance from microbes." The effect is to tip the immune system in the direction of overreaction, either to outside stimuli or even to the body's own cells. If the former, the result is allergies or asthma. Sachs writes that "children who receive antibiotics in the first year of life have more than double the rate of allergies and asthma in later childhood." But if the immune system turns on the body itself, you see irritable bowel syndrome, lupus or multiple sclerosis, among the many autoimmune diseases that were virtually unknown to our ancestors but are increasingly common in the developed world.
Exerpts:
In terms of infectious disease, the environment of the American suburb is unquestionably a far healthier place than most of the rest of the world. But we've made a Faustian bargain with our antibiotics, because most researchers now believe that our supersanitized world exacts a unique price in allergies, asthma and autoimmune diseases, most of which were unknown to our ancestors. Sachs warns that many people drew precisely the wrong conclusion from this, that contracting a lot of diseases in childhood is somehow beneficial. What we need is more exposure to the good microbes, and the job of medicine in the years to come will be sorting out the good microbes from the bad.
And that's an essential step in the development of a healthy immune system. The immune reaction relies on a network of positive and negative feedback loops, poised on a knife edge between the dangers of ignoring a deadly invader and over-reacting to a harmless stimulus. But to develop properly it must be exposed to a wide range of harmless microbes early in life. This was the normal condition of most human infants until a few generations ago. Cover the dirt on the floor of the hut, banish the farm animals to a distant feedlot, treat an ear infection with penicillin, and the inflammation-calming interleukin-10 reaction may fail to develop properly. "Modern sanitation is a good thing, and pavement is a good thing," says Sachs, "but they keep kids at a distance from microbes." The effect is to tip the immune system in the direction of overreaction, either to outside stimuli or even to the body's own cells. If the former, the result is allergies or asthma. Sachs writes that "children who receive antibiotics in the first year of life have more than double the rate of allergies and asthma in later childhood." But if the immune system turns on the body itself, you see irritable bowel syndrome, lupus or multiple sclerosis, among the many autoimmune diseases that were virtually unknown to our ancestors but are increasingly common in the developed world.