A Newly Discovered Human Organ System
In the last article, information was presented about the fact that all humans are normally populated with trillions of microscopic organisms (bacteria, viruses, fungi) that are known as microbes. Collectively, all of these organisms together form the Human Microbiome. The majority of the bacterial microbes are colonized in the gut and for the purposes of this article, we will refer to the gastrointestinal bacteria simply as the Microbiome.
Our bodies exist and thrive on many biological systems that carry out specific functions for everyday living. They are called organ systems because at the center of these systems is a vital organ or group of organs. As examples, the heart is the central organ of the cardiovascular system and the gastrointestinal system functions with multiple organs (stomach, intestines, pancreas, etc.). Recent scientific studies have uncovered a new organ system, the Microbiome. Central to the Microbiome is the gut (intestines) and the microscopic organisms that inhabit this organ. The Microbiome functions as an organ system through its bacteria producing biologically active substances that influence the function of other organ systems.
The cells of our body exist in an ecosystem with the bacteria of the Microbiome, interacting in a mutually beneficial manner. The Microbiome and its population of bacteria are as distinctive to each individual as is their fingerprint. Who we are as a person as well as the state of our health depends on which bacteria our Microbiome is hosting.
The bacterial community that comprises the typical Microbiome is much like the people that populate a city. There are good guys, bad guys, and apathetic or indifferent types. The good bacteria have beneficial metabolic effects on other organ systems thus assisting in health maintenance. If the bad bacteria flourish, they can multiply and cause illness. The neutral bacteria are relevant because they occupy space in the gut, limiting territory that could provide additional space for the bad bacteria to inhabit.
The Microbiome consist of living organisms and thus they require nourishment for viability and functionality. Their food supply is determined by which foods they are offered from the diet of their human host. The multitude of bacteria have variable palates and thrive on different foods. Most of the good bacteria prefer fiber rich foods such as fruits and veggies. Bad bacteria tend to prefer sugars, starches, and fatty foods. The bacteria that receive their preferable foods proliferate more than others and send messages to the brain stimulating their human host to crave more of those types of foods. These cycles with bacterial intermediaries are thought to contribute to obesity. Could the current obesity epidemic be related to an imbalance in an individual’s Microbiome?
Animal studies have shown that if the Microbiome of an obese animal is replaced with the Microbiome of a thin animal, the obese animal gradually loses weight and becomes thin. So, how is a Microbiome replaced? Currently this is accomplished with what is known as a fecal transplant. Yes, even though you might question your thoughts, the fact is that ‘poop’ from a healthy donor is instilled into the colon of a needy recipient.
It was suggested earlier that gut bacteria communicate with our brain by influencing food preferences. Further evidence supporting this phenomenon is the result of a study whereby normal behaving animals received fecal transplants from anxious and depressed humans and the animals subsequently demonstrated abnormal emotional behavior compatible with anxiety and depression. The experiment was repeated using the same animal species whose vagus nerves (a long cranial nerve that travels from the gut to the brain) were severed and these animals showed no emotional changes after receiving a transplant from the same donors. This does suggest that bacteria in our gut communicate with our brain by producing neurotransmitters (messengers) that travel to the brain via the vagus nerve.
Currently, fecal transplantation is performed in several clinics specifically to treat a common bacterial infection of the colon caused by the bacteria C. difficile and known as C. diff colitis. This is one of the bad bacteria that normally resides in the colon but doesn’t cause disease while being held in check by good bacteria. With prolonged use of antibiotics, good bacteria can be killed thus allowing the C. diff bacteria to multiply and cause severe life -threatening diarrhea. Because some C. diff bacteria are resistant to all antibiotics there have been 14,000 deaths from the disease. Thus far, fecal transplantation has produced a cure rate of 90-95%, in many cases in a matter of 48 hours! Somewhat ironically, the only significant complication noted thus far has been weight gain by recipients when obese donors supplied the ‘poop’!
Thousands of investigations involving the Microbiome are in progress and we will attempt to keep you informed. This research is obviously difficult while dealing with the trillions of bacteria who make the human body their home.
As a side note, hopefully this information will influence one’s decision making when considering the Colon Cleansing procedure offered by some alternative medicine providers. There is no scientific evidence that this “therapy” is beneficial and actually may be damaging to a newly recognized organ system, the Microbiome.
Dr. Tippett is the founder of Comprehensive Quality Healthcare Providers, a concierge internal medicine practice, located at 1210 Commerce Dr. Greensboro, Ga. 30642. He may be contacted at 706-510-3659. Visit his webpage at www.drtippett.com