Wednesday, June 5, 2013

A Healthy Microbiome is a Healthy You

            The human microbiome is the unsung hero of our health and happiness, or lack thereof. While it’s entirely invisible and rarely even comes up in conversation, let alone medical facilities, it plays an extremely important role in the regulation of human immune systems and bodily function. The human microbiome is extensive and high variable, serving many functions in our bodies, the most notable of which are immune system support and aiding in proper digestion. Upsets in our bacteria can cause both of these things to fail. While to most the skin and internal microbiome we carry with us is wholly unimportant and generally unknown, the fact is that it is a massive part of our livelihood and in sheer numbers, our human cells are outnumbered by our microbes more than 10:1. While the research into the nature of our microbiomes is just beginning there has already been a large amount of evidence linking a healthy microbiome to a healthy, or at least healthier, person in general.

The proportions of bacteria types on and in the
body depend largely on location.
            The concept of “probiotics” has become reasonably common in recent years, with many products available that advertise their probiotic content, such as yogurts, supplements, and some drinks. These specific items are aimed at supporting the microbes residing in our intestines, more commonly referred to as “gut flora.” Aside from the skin of the forearm, which has been shown to have “the richest community with an average of 44 species” of microbes present, the gut is one of the most microbe dense areas of our bodies (Yong 2010). A healthy gut leads to a healthier life, and there have been studies recently linking obesity to the health of the gut flora. While  not historically as much of a problem, the homogenization of the average American diet has created culture with a less microbially diverse digestive system, which has in turn led to a heavier nation, as well as a sicker one. Current scientific research positively links reduced bacterial diversity in the gut with obesity, something that should serve as a big red flag for our country (Ley 2010).

Babies need a healthy microbiome, too!
            It should be no real surprise that the basis for our microbiome comes from our parents, especially from our mothers, during our births. The process of natural birth introduces the mother’s gut and vaginal microbes and shortly after birth, we’re exposed to the skin microbiome as well. This is a vital process for a healthy immune system, and, as it turns out there are much higher rates of allergies and asthma in children born through C-sections, a sterile process allowing the newborn to be exposed to only the mother’s skin microbiome (Pollan 2013). Of course, this lack of exposure can easily be corrected by essentially inoculating the infant with the proper microbes. As unappealing as that sounds, the fact remains that it has been proven many times over that the microbiome present in and on our bodies is crucial for our quality of life, if not our survival, in general.

            The big question is really why, as a nation, our microbes have failed us? And the answer is that they haven’t. We’ve failed them. Bacteria does not exist for us to use and it surely isn’t something we can always assume we’ll have the right amount of in our bodies, especially if we’re not willing to take care of them, ourselves. There are many different methods of exposure to the proper microbes, outside of the exposure we receive from our mothers at birth, and yet so many people lack the proper microbiome, these days. Ironically, our desire for cleanliness and convenience has been our downfall.

High fat diets promote obesity not only in humans.
            Many microbes can come into contact with our skin through things such as dirt and pollen. These microbes are essential for fighting allergies and improving the immune system. The problem is that many parents don’t want to deal with dirty kids, and so they’re discouraged from digging around in (and sometimes eating) dirt. This is something that has been termed the “hygiene hypothesis” which is essentially that a lack of exposure to microbial stimulation in early life causes deficient immune response to allergens in later life (Huffnagle 2010). We’ve also become so obsessed with eating “clean” food and using pesticides and washing out produce that we remove much of the bacteria from the food we eat, as well, drastically reducing our exposure to the good bacteria our bodies need, not just the bad. And it’s not just that we’ve become almost too clean. As is well-illustrated in a video by Jessica Green titled “You are your microbes,” the standard American diet is definitely not helping our situation at all. Eating a diet based heavily on fats and starches and forgoing the greens does supply food for some of the gut flora we carry with us, but all of the bacteria that depend on the micronutrients provided by plant materials and a more diverse diet can no longer survive (Green 2013). In fact, it has been shown that obesity has been specifically linked to one bacterium called Enterobacter that thrives under high fat diets, though it is surely not the only bacterium that contributes to large amounts of weight gain. However, after test subjects with excess amounts of this particular bacteria consumed a diet of mainly whole grains and probiotic foods, those high in micronutrients meant to support diverse gut flora, significant amounts of weight were lost and associated medical issues such as diabetes and hyperinsulinemia were drastically better (Fei 2013).

A diverse microbiome is a healthy microbiome.
            The healing effects of a healthy microbiome don’t stop there, however. Though it doesn’t sound pleasant, fecal transplantation has become a promising cure to many intestinal illnesses like Crohn’s disease and ulcerative colitis, debilitating illnesses that have historically shown little response to standard medicines (Spectrum Health 2013). That the proper balance of gut flora can cure these things and promote healthy weight and autoimmune response is astounding, and should be taken as a hint that we need to clean up our act. In reality, keeping up a healthy microbiome is as easy as eating a balanced diet and getting a bit of time outside each day. Gardening would kill two birds with one stone, even. A healthy microbiome is a healthy you, and for something so easy to accomplish that seems like something worth paying attention to.

Popular Media:

Green, Jessica. “You are your microbes.” Online video clip. Youtube. Youtube, Jan. 7, 2013. May 28, 2013

Pollan, Michael. “Some Of My Best Friends Are Germs.” New York Times. New York Times, May 15, 2013. Web. May 28, 2013.

Yong, Ed. “An introduction to the microbiome.” National Geographic Magazine. National Geographic, August 8, 2013. Web. May 28, 2013.

Primary Literature:

Fei, Na and Liping Zhao. “An opportunistic pathogen isolated from the gut of anobese human causes obesity in germfree mice.” The ISME Journal. Nature, December 13, 2012. Web. May 28, 2013.

Huffnagle, Gary B. “The Microbiota and Allergies/Asthma.” PLoS Collections. PLoS Pathogens, May 27, 2010. Web. May 28, 2013.

Ley, Ruth E. “Obesity and the Human Microbiome.” Medscape News. Medscape, 2010. Web. May 28, 2013.