The Other Half of You – Why the Human Microbiome is so important to our health, and why it could be going extinct.

map-of-the-healthy-human-microbiome

Cooties, germs, bacteria, or whatever you call them have been public enemy number one for decades, maybe even centuries. Ever since we discovered the little one celled creatures and realized that they were the cause of some of our worst diseases, our species has been trying to eradicate them by any means necessary. That war still rages on in the form of antibiotics, hand sanitizer, vaccines, and an irrational fear of things we can’t even see, but automatically assume are there. In effect, this war has turned us all into relative germaphobes (compared to ages past when people were scarcely aware of them).

If science didn’t prove the existence of microorganisms, our behavior could very well be described as superstitious, especially considering the many rituals we engage in to protect ourselves. The ancient Greeks would touch the ground when they heard thunder to avoid getting struck by lightning, and we similarly use hand sanitizer or wash our hands on a regular basis to avoid illness. Yes, science proves that our modern rituals are effective, but most of us don’t really know that for ourselves any better than an ancient Greek person knew that his ritual kept the lightning away (his own experience would validate his belief, as getting hit by lightning is very unlikely). We are simply following the popular belief, as the Greeks did, whether we have done the science ourselves or not.

I bring all this up not to discourage the use of hand sanitizer, but to illustrate how we as humans will do almost anything to protect ourselves before we really know what is going on. If it were told by those in authority that touching the ground will prevent a lightning strike from hitting you, the most common Greek response was probably “Better safe than sorry,” right? The same thing goes for microorganisms and the many products we use to fight them, but there’s a catch. It turns out that microorganisms, specifically bacteria, are usually a good thing, and killing them is having a huge impact on our health. After all, they make up not just half, but 90% of all the cells in your body.

The human microbiome, or the ecosystem of bacteria that live on and inside the human body, is a vast, complex, and innumerable system of checks and balances. We could not live without this system, and each microbiome is uniquely adapted to the individual. In other words, the proportions of various bacteria living inside you, and even the bacteria themselves, are different than those living inside of any other human being. So if you killed all or some of the bacteria in your body, you could be causing the extinction of entire species of microorganisms.

According to Carl Zimmer of the New York Times, the good bacteria inside us “digest compounds in our food that would otherwise be indigestible… [and] help tutor the immune system, so that it attacks pathogens without overreacting and damaging the body itself. The microbiome can even fend off disease-causing bacteria.”

It is quickly becoming evident through modern science that the human microbiome plays a vital role in our overall health, especially our immune system, and many modern diseases can be linked to having an imbalanced microbiome. This is true from birth, and studies suggest that a lack of a healthy microbiome early in life may lead to autoimmune diseases such as rheumatoid arthritis and diabetes, as well as other problems like allergies and obesity. So why is the human microbiome off kilter?

One of mankind’s greatest achievements, if not the greatest, was the development of antibiotics. They have certainly saved the lives of millions of people, and I would never want anyone to get the wrong idea about them. Modern medicine, however, has slowly realized that what cured so many ancient illnesses might be causing new ones, and they have only scratched the surface in the emerging field of study concerning the human microbiota. Very little conclusive research has been conducted on the human microbiome and what effects antibiotics may be having on it, but what we do know is certainly enough to raise eyebrows.

Wide-spectrum antibiotics, previously considered better than narrow-spectrum varieties because they could target a greater variety of microbes, have unfortunately had collateral damage, killing the good along with the bad. Since we inherit much of our microbiome from our mothers, some theories suggest that we are losing key members of the microbiome with each generation that is born and continues to kill off their own microbiome with antibiotics and modern sanitation practices.

Furthermore, our continued effort to kill the bad bugs that live inside us has promoted the growth of the really bad ones, or the bugs that are resistant to antibiotics. New antibiotics are not being developed fast enough to counter these “superbugs,” but the question may be raised whether more antibiotics are the best solution, considering the unintended consequences of their use.

If this seems like a gloomy picture, there is hope. As we learn more about the human microbiome, we can develop better treatments to keep it healthy. Such treatments already exist to cure problems in the intestine, and they involve repopulating the intestinal track with the right balance of bacteria that will make a person healthy. Similar procedures are done for cancer patients, whose microbiomes can be decimated by radiation or chemotherapy, in which case samples of their microbiota are preserved and reintroduced after their treatments. As we discover more problems related to imbalances in the human microbiome, we will inevitably discover the solutions to fix those imbalances. The challenge is finding those solutions before too much of the microbiome has gone extinct.

Preserving the microbiome, like any endangered species, is a time sensitive matter. You can’t bring back what’s already gone, so identifying and characterizing as much of the microbiota before they die off is imperative. That’s what the government funded Human Microbiome Project is aiming to do, but the task is monumental, considering the vast spectrum of microbes that live inside us.

What can everyday citizens like us do to help? That’s a tough question, and it’s a narrow line to walk when you’re trying to find the balance between protecting yourself and preserving your microbiome. In situations where the danger is acute, such as in hospitals or when someone is gravely ill, I don’t think anyone would discourage the use of sanitation products or antibiotics. There are situations, however, when we might want to ask a lot of questions if antibiotics are being considered, or forego a habitual hand-wash when there is no suspected need for it.

One important situation is with our children. As a new father, I was amazed when my daughter was treated with antibiotics less than a day after she was born. I’m grateful for that, of course, because she was born with a case of pneumonia and there were indications of infection, but it goes to show how children can be exposed to these treatments very early in life.

Take ear-aches, for example. They are one of the most common illnesses for babies, and almost always treated with antibiotics despite the fact that ear infections are almost always caused by a viral infection rather than bacteria. Of course, the antibiotics may help with secondary infections in these cases, but it may be worth asking questions to understand the pros and cons of whatever treatment is being considered, and whether it is absolutely necessary. Pediatrician Claire McCarthy notes that, with ear-infections, “more than half of kids will start to feel better in a day with or without antibiotics, and in a week that number goes up to three-quarters.”

There are more things to be done on the community level than on the individual level, but we can all help raise awareness of this issue. In the words of Dr. Martin Blaser, as quoted by PBS Newshour, “doctors should stop over-prescribing antibiotics, especially to young children. Researchers should work on new antibiotics that can target specific infections, minimizing the good bacteria casualties, and potentially developing effective probiotics — these are beneficial microbes introduced into the body. And go easy on the hand-sanitizers and anti-bacterial soaps.”

In the end, the issue of protecting the human microbiome is one that must be addressed with a grain of salt. It’s about raising awareness, not dictating the continuation or cessation of sanitation practices. That being said, that raised awareness is supposed to influence people’s choices on an individual level so that we can all be more conscientious about the health of our species. Will this information make an immediate impact on your life? Maybe, but I don’t expect it to. Instead, I hope that one day, as you reach for the hand sanitizer, or as you talk with your doctor, this issue might pop into your head and you will think more deeply about your health. You will make informed choices, and that’s the best thing any of us can do.

Sources:

http://www.actionbioscience.org/genomics/the_human_microbiome.html

http://en.wikipedia.org/wiki/Human_Microbiome_Project

http://www.babycenter.com/0_ear-infections-in-babies_83.bc#articlesection3

http://www.webmd.com/cold-and-flu/ear-infection/understanding-otitis-media-basics

http://www.pbs.org/newshour/updates/theres-extinction-happening-stomach/

http://www.parents.com/baby/health/ear-infection/the-right-way-to-treat-an-ear-infection/

http://www.scientificamerican.com/article/strange-but-true-humans-carry-more-bacterial-cells-than-human-ones/

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