May 17, 2014 By Dr. Mercola
The interconnectedness of your gut, brain, immune, and hormonal systems is impossible to unwind. The past few years has brought a scientific flurry of information about how crucial your microflora is to your genetic expression, immune system, body weight and composition, mental health, memory, and minimizing your risk for numerous diseases, from diabetes to cancer.
Researcher Jeroen Raes, featured in the TED Talk, discovered that you might even belong to one of a few “microflora types”—which are similar to blood types. Research into the human microbiome is in its infancy, and there is much we do not yet understand.
That said, there are some facts of which we are already certain. It is becoming increasingly clear that destroying your gut flora with pharmaceutical drugs, harsh environmental chemicals, and toxic foods is a primary factor in rising disease rates.
Recent research suggests intestinal inflammation may play a critical role in the development of certain cancers. Until we begin to appreciate this complex relationship, we will not be able to prevent or intervene effectively in many of the diseases that are devastating people’s lives today.
In order for true healing and meaningful prevention to occur, you must continuously send your body messages that it is safe, not under attack, and that it is well nourished, supported, and calm. This article will focus on exactly how you can send your body these messages and why caring for your personal microbiome is so critical to every aspect of your health.
How Can You Feel Lonely with 100 Trillion Constant Companions?
The idea that microorganisms are to be “divided and conquered” is now an outdated view of our world. We not only live with them and are surrounded by them, but we depend on them for our very existence. Pamela Weintraub skillfully describes the symbiosis between humans and microorganisms in her June 2013 article in Experience Life magazine.1
Your body is a complex ecosystem made up of more than 100 trillion microbes that must be properly balanced and cared for if you are to be healthy.
This system of bacteria, fungi, viruses, and protozoa living on your skin and in your mouth, nose, throat, lungs, gut, and urogenital tract, is referred to as the “human microbiome.” It varies from person to person based on factors such as diet, health history, geographic location, and even ancestry.
When your microbiome falls out of balance, you can become ill. Those organisms perform a multitude of functions in key biological systems, from supplying critical vitamins to fighting pathogens, modulating weight and metabolism.
This army of organisms also makes up 70 percent of your immune system, “talking” directly to your body’s natural killer T-cells so that they can tell apart your “friendlies” from dangerous invaders. Your microbiome also helps control how your genes express themselves. So by optimizing your native flora, you are actually controlling your genes.
Gut Instincts—Your Second Brain Talking
Your microbiome is closely intertwined with both of your brains—yes, you have TWO! In addition to the brain in your head, embedded in the wall of your gut is your enteric nervous system (ENS), which works both independently of and in conjunction with the brain in your head. According to New Scientist:2, 3
“The ENS is part of the autonomic nervous system, the network of peripheral nerves that control visceral functions. It is also the original nervous system, emerging in the first vertebrates over 500 million years ago and becoming more complex as vertebrates evolved—possibly even giving rise to the brain itself.”
Your ENS is thought to be largely responsible for your “gut instincts,” responding to environmental threats and sending information to your brain that affects your well-being.
I’m sure you’ve experienced various sensations in your gut that accompany strong emotions such as fear, excitement, and stress. Feeling “butterflies” in your stomach is actually the result of blood being diverted away from your gut to your muscles, as part of the fight or flight response.
These gut reactions happen outside of your conscious awareness because they are part of your autonomic nervous system, just like the beating of your heart. Your ENS contains 500 million neurons. Why so many? Because eating is fraught with danger:4
“Like the skin, the gut must stop potentially dangerous invaders, such as bacteria and viruses, from getting inside the body.
If a pathogen should cross the gut lining, immune cells in the gut wall secrete inflammatory substances including histamine, which are detected by neurons in the ENS. The gut brain then either triggers diarrhea or alerts the brain in the head, which may decide to initiate vomiting, or both.”
We now know that this communication between your “two brains” runs both ways and is the pathway for how foods affect your mood. For example, fatty foods make you feel good because fatty acids are detected by cell receptors in the lining of your gut, which then send warm and fuzzy nerve signals to your brain.
Knowing this, you can begin to understand how not only your physical health but also your mental health is deeply influenced by the health of your gut and the microbial zoo that lives there. Your gut microbes affect your overall brain function, from basic mood swings to the development of serious illnesses like autism, Alzheimer’s disease, and schizophrenia.
When It Comes to Inflammation, Your Microbiome Rules
Your gut is the starting point for inflammation—it’s actually the gatekeeper for your inflammatory response. According to Psychoneuroimmunologist Kelly Brogan, your gut’s microorganisms trigger the production of cytokines. Cytokines are involved in regulating your immune system’s response to inflammation and infection. Much like hormones, cytokines are signaling molecules that aid cell-to-cell communication, telling your cells where to go when your inflammatory response is initiated.
Most of the signals between your gut and your brain travel along your vagus nerve—about 90 percent of them.5 Vagus is Latin for “wandering,” aptly named as this long nerve travels from your skull down through your chest and abdomen, branching to multiple organs.6
Cytokine messengers produced in your gut cruise up to your brain along the “vagus nerve highway.” Once in your brain, the cytokines tell your microglia (the immune cells in your brain) to perform certain functions, such as producing neurochemicals. Some of these have negative effects on your mitochondria, which can impact energy production and apoptosis (cell death), as well as adversely impacting the very sensitive feedback system that controls your stress hormones, including cortisol.
So, this inflammatory response that started in your gut travels to your brain, which then builds on it and sends signals to the rest of your body in a complex feedback loop. It isn’t important that you understand all of the physiology here, but the take-away is that your gut flora’s influence is far from local! It significantly affects and controls the health of your entire body.
1 Experience Life June 2013
2 New Scientist December 17, 2012
3 Neurosciencestuff December 18, 2012
4 New Scientist December 17, 2012
5 American Journal of Physiology December 2002
6 WiseGeek Vagus Nerve