Wired
March 2014
p. 58
Microbiologist Martin Blaser of New York University School of Medicine states that humans are in the midst of an extinction crisis, because many species of germs are disappearing from the body. Blaser argues in his book--Missing Microbes: How the overuse of antibiotics is fueling our modern plagues--that while antibiotics have saved a good number of lives, they are an assault on the human microbiome. His experiments have connected the resulting extinctions of germs to disorders that include asthma and obesity. The human body needs to be looked at less as a battlefield to be conquered and more as gardens to be tended.

Glaser has studied the Heliobacter pylori bacterium, which causes gastric cancer and ulcers. This sounds like something that should be wiped out. And while H. pylori is responsible for four-of-five cases of stomach cancer, it also is found in healthy people across the globe. Further research revealed that those who have H. pylori are less likely to have childhood-onset asthma and hay fever.

The average person harbors several thousand species of microbes within their body. They can be found on the skin; in the mouth within the teeth and gums, as well as on the top and bottom of the tongue; and especially within the bacteria-dense colon. These bacteria help extract energy from food and are important for making vitamins for the body. The good microbes help fight off infection. Microbes also affect the brain, because much of the serotonin is made in the gut by neuroendocrine cells that communicate with the microbiotia. 

Serotonin is a neurotransmitter that contributes to feelings of well-being and happiness. 90% of the body's total serotonin is found in the gut, where it regulates intestinal movements. The remainder is synthesized in the central nervous system where it is responsible to regulate appetite, mood, and sleep. Serotonin also serves in cognitive functions that include learning and memory. It also functions as a vasoconstrictor to narrow blood vessels. This is important to stop hemorrhage and acute blood loss, as well as conserving body heat.

Because microbes serve important functions within the body, a proper balance needs to be maintained. A prevalent view has been that a dose of antibiotic to arrest infection cannot be harmful. But the data show otherwise. The approach has to change. Because research is demonstrating the effects, a physician has to take the risks into account. A new thinking has to come into play. Understanding that a course of antibiotics could increase the chance of asthma, Crohn's disease, diabetes, or obesity--a doctor may take a more reserved approach, waiting a day to see if the patient becomes better.

Glaser's hypothesis is that each time a person takes antibiotics, a few species of microbes go extinct within the individual. He yet does not have proof of this, but it is known that the population size of some of the organisms is very small. For years now, it has been thought that antibiotics will have short-term effects in the body--and that the system will rebalance itself. But Glaser questions whether this is true, commenting that science does not know whether certain less common microbes are totally eradicated after a course of antibiotics.

Glaser notes that better diagnostics are needed to identify bacterial infections from viral infections. And if it is a bacterial infection, which bacteria is it? It is important to develop specific drugs to combat specific bacteria--rather than administering a broad-spectrum antibiotic. The tradeoff is to spend the time and money to develop diagnostics and the specific drugs--or to spend the time and money at health clinics to address the illnesses that are being caused because necessary and vital microbes have been expunged from the body.

Then there is the preoccupation with hand sanitizers. Glaser acknowledges that its use is important in hospitals, but he questions the rationale for all the other places where it is used and the frequency of its use. Hand sanitizers do not have antibiotics in them, but they do contain antibacterials such as triclosan. Triclosan has been added to deodorants, soaps, the fibers of clothes, and the surfaces of kitchen & office utensils. Its use is pervasive; Glaser believes this is a germophobia that is unsupported.

When it comes to probiotics, Glaser sees these as being generally safe--but notes that they have not been rigorously tested in clinical studies. The future hold great promise for probiotics, but research needs to be undertaken to discover what their specific activities are and when they need to be used. Perhaps a particular bacteria will be a good treatment for children with asthma, and another will ease the effects of rheumatoid arthritis. Microbes have been harnessed to make bread and beer, so the future is promising for their use in promoting health and combating illness.
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