Much attention as of late has been turning to the fauna of the digestive tract, and how it affects our health. With recent studies showing the affects of processed food and over-use of antibiotics causing harm to the natural "good" bacteria that we need for everything from digestion to our immune system, it may be time we turn our attention to how to keep our bodie's naturally occuring beneficial bacteria helpful and functioning properly.
Most of our microbes inhabit the colon, the final loop of intestine, where they help us break down fibers, harvest calories, and protect us from micro-marauders. But they also do much, much more. Animals raised without microbes essentially lack a functioning immune system. Entire repertoires of white blood cells remain dormant; their intestines don't develop the proper creases and crypts; their hearts are shrunken; genes in the brain that should be in the "off" position remain stuck "on." Without their microbes, animals aren't really "normal."
What do we do for our microbes in return? Some scientists argue that mammals are really just mobile digestion chambers for bacteria. After all, your stool is roughly half living bacteria by weight. Every day, food goes in one end and microbes come out the other. The human gut is roughly 26 feet in length. Hammered flat, it would have a surface area of a tennis court. Seventy percent of our immune activity occurs there. The gut has its own nervous system; it contains as many neurons as the spinal cord. About 95 percent of the body's serotonin, a neurotransmitter usually discussed in the context of depression, is produced in the gut.
Additionally, the article goes on, to show a corrolation between children exposed to natural positive bacteria having a lower rate of allergies and other ailments.
So the gut isn't just where we absorb nutrients. It's also an immune hub and a second brain. And it's crawling with microbes. They don't often cross the walls of the intestines into the blood stream, but they nevertheless change how the immune, endocrine, and nervous systems all work on the other side of the intestine wall.
Science isn't always consistent about what, exactly, goes wrong with our microbes in disease situations. But a recurrent theme is that loss of diversity correlates with the emergence of illness. Children in the developing world have many more types of microbes than kids in Europe or North America, and yet generally develop allergies and asthma at lower rates than those in industrialized nations. In the developed world, children raised in microbially rich environments—with pets, on farms, or attending day care—have a lower risk of allergic disease than kids raised in more sterile environments.
Additional concerns that modern medicine is depriving the body of microbes that it needs to properly function:
Those who study human microbial communities fret that they are undergoing an extinction crisis similar to the one afflicting the biosphere at large—and that modern medicine may be partly to blame. Some studies find that babies born by C-section, deprived of their mother's vaginal microbes at birth, have a higher risk of celiac disease, Type 1 diabetes, and obesity. Early-life use of antibiotics—which tear through our microbial ecosystems like a forest fire—has also been linked to allergic disease, inflammatory bowel disease, and obesity.
Which brings us to the question more and more scientists are asking: If our microbiota plays a role in keeping us healthy, then how about attacking disease by treating the microbiota? After all, our community of microbes is quite plastic. New members can arrive and take up residence. Old members can get flushed out. Member ratios can shift. The human genome, meanwhile, is comparatively stiff and unresponsive. So the microbiota represents a huge potential leverage point in our quest to treat, and prevent, chronic disease. In particular, the "forgotten organ," as some call the microbiota, may hold the key to addressing our single greatest health threat: obesity.
Read more of the original article here: http://www.motherjones.com/environment/2013/04/gut-microbiome-bacteria-weight-loss?page=2